Showing papers in "Systematic Botany in 1977"

Cytotaxonomical atlas of the pteridophyta

Abstract: Cytotaxonomical atlas of the pteridophyta , Cytotaxonomical atlas of the pteridophyta , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Diurnal and Nocturnal Pollination of Catalpa speciosa (Bignoniaceae)

Abstract: Catalpa speciosa is an obligate outcrosser pollinated diurnally by bumblebees and carpenter bees and nocturnally by various moths. More flowers are pollinated during the day, but there is no significant dfference between day and night in the number of pollinations per hour. The quantity of nectar produced at night is significantly greater than during the day, but the sugar concentration of the nectar and the totael sugar per flower is greater during the day. The quantity of nectar and sugar concentrations of C. speciosaflowers changefrom those typical of bumblebee-pollinatedflowers during the day to those typical of moth-pollinated flowers at night. Most flowers have one principal pollinator with occasional visitors (Grant, 1976) or a wide variety of pollinators (Faegri & van der Pijl, 1971; Proctor & Yeo, 1973). The data we present show that Catalpa speciosa Warder (Bignoniaceae) has features characteristic of flowers that are pollinated by either large bees or moths. Catalpa speciosa is pollinated diurnally by large bees and nocturnally by moths, and both types of insects are common and effective pollinators. Catalpa speciosa is native to alluvial forests from southern Indiana to Arkansas and Texas (Gleason & Cronquist, 1963). It is cultivated as an ornamental throughout the Great Lakes states where it has become naturalized in riparian habitats similar to those of its natural range. It blooms in the late spring, the flowers being approximately 4 cm long and 5 cm wide and in inflorescences of five to 30. The broadly tubular corolla is white with scattered purple spots and approximately the last centimeter of each petal flares outward (Fig. la). The flowers are oriented horizontally and a small landing platform is formed from the lower portion of the corolla (Fig. lb). The bottom of the interior of the corolla tube has both mechanical an-d color nectar guides. A shallow central groove is defined by two lateral ridges extending most of the length of the corolla tube (Fig. 1c). Flanking the ridges on either side of the groove are two deep yellow nectar guides extending over half the distance to the base of the flower (Fig. la). The stigma and two stamens, one to either side of the stigma, are positioned medially along the upper side of the corolla tube, directly above and opposite the groove. The stamens ' We thank E. Steiner, who made the facilities of the Matthaei Botanical Gardens available; E. G. Voss, who identified the moths; F. C. Evans, who identified the bees; C. Augspurger, J. Edwards, L. Thomson, and J. Winsor, who criticized the manuscript; J. G. Lacy for the drawing; H. G. Baker for some unpublished data; and G. F. Estabrook, who contributed to many phases of this work. 2 Botany, Division of Biological Sciences, University of Michigan, Ann Arbor, MI

Local Differentiation for Phenotypic Plasticity in the Annual Collomia linearis (Polemoniaceae)

Abstract: A population of Collomia linearis was subdivided into two plots, one in a relatively disturbed site free from interspecific competition and the other in a meadow habitat characterized by high vegetative cover and considerable interspecific competition. Greenhouse progenies of the two subpopulations differed significantly with respect to seven morphological characters, indicating that the two subpopulations were genetically differentiated. Analysis of nine morphological characters in progenies subjected to 36 different environmental conditions revealed that plants of the disturbed plot were phenotypically more plastic than those of the meadow plot. It is concluded that phenotypic plasticity represents a genetic response and may arise through local differentiation under conditions of disruptive selection. Phenotypic plasticity represents the amount by which the genotypic expression of a character is changed by environmental conditions (Bradshaw, 1965; Davis & Heywood, 1963). Bradshaw reviewed evidence that demonstrates that plasticity is under genetic control and is alterable by selection. The potential for evolutionary differentiation between closely adjacent plant populations has been reviewed by Jain and Bradshaw (1966), Ehrlich and Raven (1969), and Bradshaw (1972) and has been empirically demonstrated by numerous studies (i.e., Bradshaw, 1959; Aston & Bradshaw, 1966; Snaydon, 1970; Linhart, 1974; Schaal, 1975). Such differentiation is often interpreted as adaptive with respect to the characters and divergent environments being compared. These studies lead to the hypothesis that phenotypic plasticity may result from disruptive selection within local plant populations. This paper presents evidence of local differentiation for phenotypic plasticity in Collomia linearis Nuttall (Polemoniaceae). Collomia linearis is an autogamous annual, occurs over a relatively broad range of habitats throughout western North America, and displays considerable phenotypic variation within and among natural populations (Grant, 1959; Grant & Grant, 1965; Hitchcock et al., 1959).

Does Common Equal Primitive

Abstract: One criterion that has been suggested as a basis for estimating the direction of evolutionary trends among the states of a character is to choose for the primitive state the one that occurs most frequently. A concept is presented of what it means for a character to sttpport an estimate of evolutionary relationships. It is argtued that if the common state is chosen as primitive, then more characters can support the same estimate of evolutionary relationships. Estimating evolutionary relationships among plant species (or higher taxa) continues to be one of the fascinations of modern plant systematics. Recent estimates based on traditional considerations have been published by Takhtajan (1969) and Cronquist (1968). Estimates based on molecular data have been made for selected species by Boulter et al. (1972). Numerous estimates of the evolutionary relationships within various lower taxa have been constructed, many using various "objective" methods recently suggested. Many workers approach constructing an estimate of evolutionary relationships among the species of a genus or family by recognizing several bases for comparison (characters) and by recording the description of those bases (character states) for the various species under study. In practice this procedure need not always be carried out at the species level. For example, genera could be compared and described instead of species. Thus, I shall use the term evolutionary unit (EU) to refer to the entity that is described by a character state, and I shall refer to the collection of EU's whose historical relationships are to be estimated as the study collection. If the approach of structuring data as characters is taken, the problem of estimating evolutionary relationships is one of determining an evolutionary tree for the EU's in the study based on the descriptions of the EU's given by the characters. There are many facets to the problem of estimating evolutionary relationships. What is an evolutionary unit? What should be the bases for comparison? How can the direction of evolutionary trends among the states of a character be estimated? What principles can be used to infer relative recency of common ancestry from the above considerations? How can these principles be made operational? I have earlier reviewed these questions (Estabrook, 1972) and wish to discuss here only one of them in more depth. This is the question of estimating the direction of trends among the states of a character. I University Herbarium and Botany, University of Michigan, Ann Arbor MI 48109. 2 J thank the Division of Biological Sciences and the University Computing Center for the use of computing facilities. This content downloaded from 157.55.39.153 on Mon, 19 Sep 2016 04:41:52 UTC All use subject to http://about.jstor.org/terms 1977] ESTABROOK: DOES COMMON EQUAL PRIMITIVE? 37

Morphological, Phenological, and Pollen-Distribution Evidence of Autogamy and Xenogamy in Gilia achilleifolia (Polemoniaceae)

Abstract: In three populations of Gilia achilleifoliafloral morphological and phenological characters and pollen distribution on stigmas suggest that different breeding systems are associated with the two main races of the species. The shade race has small corollas, stigmas maturing below the anthers, low pollen production, low pollen-ovule ratios, homogamy, many pollen grains per stigma, and high seed set. The sun race differs in all these characters. Gilia achilleifolia Bentham, including ssp. multicaulis (Bentham) V. & A. Grant, is an annual species endemic to California. It is composed of two races-a race occupying sunny hillsides, characterized by dense inflorescences of large, showy flowers, and a race occupying shady places, having inflorescences with fewer, smaller flowers (Grant, 1954). Evidence for the genetic control of these characters was provided by Grant in a series of reciprocal transplant studies. Flowers of the sun race have stigmas exserted beyond the anthers whereas those of the shade race have stigmas situated below the anthers. Both races are self-compatible, but the progeny of self-pollinated shade-race plants show no inbreeding depression whereas the progeny of self-pollinated sun-race plants are less vigorous than their cross-pollinated counterparts (Grant, 1954). Populations of both races are interspersed throughout the southern and central Coast Ranges (Grant, 1954). While Grant's observations of the flowers and reproductive behavior of plants of the two races of G. achilleifolia led him to postulate that the species is composed of xenogamous and autogamous races, he did not explore this supposition further. In the present study floral characters of populations of the two races, and of a population intermediate between the two, were compared. The characters are: corolla size, degree of stigma exsertion, amount of pollen produced per flower, pollen-ovule ratio, degree of dichogamy, number of pollen grains per stigma, and seed set. MATERIALS AND METHODS The three populations sampled were: a small-flowered population (SML) on the upper slopes of Mt. Diablo in Contra Costa County, a population with intermediate-sized flowers (IMD) in Del Puerto Canyon in Stanislaus County, and a large-flowered population (LGE) in Cerro 'This work was supported in part by a grant from Sigma Xi. I thank Robert Ornduff, Herbert Baker, and Dale Johnson for comments and suggestions. 2 Botany, University of California, Berkeley CA 94720.

A Systematic Histological Study of Palm Fruits. I. The Ptychosperma Alliance

Abstract: The fruit of the ei

Phenotypic Variation and Adaptation in Clarkia Section Phaeostoma

Abstract: Progenies from nine populations of six species of Clarkia, including the new species C. calientensis, were compared using a similarity index based on the sum of sign/ifcant differences for 22 morphological and developmental traits. The two most similar populations were conspec/ifc. Other populations of different species were more similar to each other than to respective conspec/ifc populations. Characteristics associated with pollination tend to have low plasticity and high interpopulation differences, suggesting rigorous selection for precisely integrated systems. Extremely plastic traits, such as the time to first flower and the number of seeds per capsule, result from a series of morphogenetic events, each of which in itself, may be highly plastic. Despite continuous adjustment, these highly plastic traits are efficient and consistent in differentiating between populations. A group of populations in woodland habitats and another in grassland habitats both show intragroup similarity in a number of characteristics, which indicate common adaptations, and some differences, which probably reflect a mode of isolation. Sympatric populations often have similar vegetative and developmental characteristics but different breeding-system characteristics; usually some characteristics of each system differentiate sympatric or adjacent populations. The greatest similarities occur in sympatric or environmentally equivalent situations, emphasizing the importance of environmental selection. Clarkia section Phaeostoma consists of C. xantiana and the C. unguiculata complex (Vasek, 1 968a). Clarkia xantiana occurs in oak-Digger Pine woodland of California's southern Sierra Nevada foothills and is easily differentiated from other species of the section by its conspicuously bilobed petals. Most populations consist of large-flowered, protandrous outcrossers, but some populations of early-flowering, small-flowered synandrogynous selfers occur in marginal habitats (Moore & Lewis, 1965). The C. unguiculata complex consists of C. unguiculata and four derivatives (Vasek, 1968a). Clarkia unguiculata is widely distributed in California's coast ranges and Sierra Nevada foothills where it commonly inhabits oak and oak-Digger Pine woodland, but it also occurs in grassland (Lewis & Lewis, 1955; Vasek, 1968a). Its many populations are highly variable in morphology, habitat, and cytology (Lewis, 1951; Lewis & Lewis, 1955; Mooring, 1958, 1960). It is generally a large-flowered, protandrous, lateblooming outcrosser (Vasek, 1958, 1964a, 1965). The derivatives have more or less restricted distributions at low elevations near the hot dry 1 Experimental portions of this study were supported by Grant GB-5914X from the National Science Foundation. I thank H. Lewis and L. Gottlieb for comments on an earlier draft of this paper. 2 Biology, University of California, Riverside CA 92521

An Analysis of the Characters and Relationships of the Tribes Eupatorieae and Vernonieae (Asteraceae)

Abstract: The Eupatorieae and Vernonieae differ in pubescence, leaf insertion, leaf shape and venation, corolla lobe form, anther bases, anther pubescence, endothecial cells, pollen grains, style branches, achene walls, and pappus. The Eupatorieae are related to the Heliantheae in the subfamily Asteroideae, and the Vernonieae are placed close to the Liabeae and Mutisieae in the subfamily Cichorioideae. The family Asteraceae has presented continuing problems for taxonomists as a result of its size and its recurring combinations of superficial characters. Efforts to understand the limits of the subfamilies and tribes have suffered particularly. Where recent detailed studies have been undertaken they rarely extend beyond the limits of a single tribe. The critical anatomical tribal distinctions of Cassini (1813) are usually acknowledged but are rarely actually observed. Taxonomists tend to rely for identifications and judgments on the more easily observed characters such as those emphasized by Bentham (1873). Evidently few workers recognize that characters that may serve well in identification are not necessarily a reliable guide to phylogeny. These approaches have perpetuated traditional concepts that contain many errors. An example is the apparent presumption of close relationship between the tribes Eupatorieae and Vernonieae. The Eupatorieae and Vernonieae bear superficial resemblance in head form and flower color, and they have been placed together in most treatments including those of Cassini (1827) and Bentham (1873). Members of these tribes are often confused in preliminary identifications by nonspecialists, and a few errors by specialists are known. The two tribes have most of their diversity in the Neotropics, a region most inadequately treated in early European studies such as that of Bentham. Nevertheless, in the last 100 years the status of the tribes seems to have entered the realm of "conventional wisdom" with most workers unaware that there is any problem. Numerous characters are now available which show that the Eupatorieae and Vernonieae are not closely related, but these characters have never been effectively summarized. Many of the characters are also potentially useful in identification. The present survey is based primarily upon my own observations, though precedents are cited where these are known. As a point of reference I use Vernoniafuertesii (Urban) H. Robinson of Hispaniola, which has the distinction of having been originally described as a Eupatorium. 1 Botany, Smithsonian Institution, Washington DC 20560.

Protogyny in the Cruciferae

Abstract: Protogyny, generally assumed to be rare or nonexistent in the Cruciferae, has been reported in at least 61 species belonging to 32 genera zn nine tribes. In Iraq 4 72 natural populations representing 91 species (nearly half the cruciferousflora) were examined, and 80 populations representing 24 species in 19 genera were found to exhibit protogyny. Protogyny is reportedfor thefirst time in 21 species and in the genera Diplotaxis, Savignya, Erucaria, Hirschfeldia, Neslia, Aubrieta, Sterigmostemum, and Sisymbrium. Protogyny, a term proposed by Hildebrand in 1867 (Rieger et al., 1968), is a mechanism that favors outcrossing by the maturation of the stigma before pollen is released in the same flower. Its effectiveness in promoting outcrossing depends on the time gap between the maturation of the pollen and the stigma. This may be two hours or less (Kerner, 1895) or two or three days (Riley, 1956; Al-Shehbaz, 1973). Protogyny is important for population survival when other mechanisms favoring outcrossing are lacking or inefficient or when the gene pool is reduced (Rollins, 1971). It has been reported in several species of Cruciferae that are predominantly autogamous (Riley, 1956; Titz, 1972; Hurka et al., 1976). In few cases, however, it has been observed in self-incompatible populations (Rollins, 1971; Stork, 1972). In the highly autogamous species the very small amount of outcrossing resulting from protogyny may be all that is needed to produce some genetic variation upon which natural selection may work. This low level of outcrossing has been estimated by Riley (1956) at 5% in Thlaspi alpestre. Although Bateman (1955) stated that "there is no protandry, no protogyny, and no dioecy in the crucifers," these three mechanisms had been reported more than 55 years earlier. Protandry was first reported by Batalin in 1889 (Knuth, 1908) in Pugionium dolabratum Maximowicz. It has also been recognized in Hugueninia tanacetifolia (Linnaeus) Reichenbach (Stager, 1914), Cardamineflexuosa Withering (listed as C. silvatica) (Gunthart, 1917), Descurainia millefolia (Jacquin) Webb & Berthelot (Schulz, 1936), Streptanthus glandulosus Hooker (Kruckeberg, 1957), S. carinatus Wright and S. culteri Cory (Rollins, 1963), and Erysimum spp. (Snogerup, 1967). Dioecism, on the other hand, was first reported by Kirk (1899) in Lepidium sisymbrioides J. D. Hooker, L. matau Petrie, and L. kawarau Petrie, but, to my knowledge, it is not known elsewhere in the Cruciferae. Perhaps the first demonstration of protogyny in the Cruciferae was made by Muller in 1873 (Hurka et al., 1976). Hildebrand (1879) reported ' Biology, College of Science, University of Baghdad, Baghdad, Iraq.

Allozyme Variation in Chenopodium fremontii

Abstract: Allozyme variation of leucine aminopeptidase, glutamate-oxaloacetate transaminase and phosphoglucosisomerase was examined in Chenopodium fremontii, a species widely distributed in the western United States. Plants in the northern part of the range (western Nebraska, Wyoming, northern and western Colorado, and Utah) differfrom those in New Mexico, Arizona, and California in allelic frequencies at one gene for phosphoglucosisomerase and one gene for glutamate-oxaloacetate transaminase. The three populations from southern California are fixed for a transaminase allele that was not demonstrated to be present elsewhere. Allelic variation was encountered in six of 40 populations, and 13 individual plants, each with one heterozygous locus, were found. Chenopodium consists of annual weedy plants long recognized as taxonomically difficult due in large measure to morphological variability. Some experimental evidence (Cole, 1960, 1961; Cumming, 1959; Crawford, unpubl.) indicates that a significant component of the variation may result from phenotypic plasticity. During the past several years we have made systematic studies in Chenopodium and evaluated genetic variation within and among taxa (Crawford, 1973, 1974a,b, 1975, 1976, 1977; Crawford & Julian, 1976; Wilson, 1976a,b). This paper deals with utilizing allozymes to determine patterns of genetic variation within a single species of widespread distribution. The species under consideration, Chenopodium fremontii S. Watson, is diploid (2n = 18) and occurs throughout much of the western United States (Crawford, 1976; Keener, 1970). It is particularly abundant in Arizona and New Mexico. Greenhouse studies have demonstrated that the species is an inbreeder (Crawford, unpubl.). MATERIALS AND METHODS Three enzymes were studied: leucine aminopeptidase (LAP), which we use to designate enzymes that will hydrolyze L-leucyl-/3-naphthylamide-HCI; glutamate-oxaloacetate transaminase (GOT); and phosphoglucosisomerase (PGI). These were chosen because they consistently produced clear, sharp bands that could be scored with no difficulty. A total of 1,119 plants from 40 populations were examined for GOT 1 Supported by National Science Foundation grants GB-29793X, BMS 74-21384, and DEB77-21727 and a Division of Basic Research Grant, College of Arts and Sciences, University of Wyoming. We thank E. G. Meyer and E. B. Jakubauskas, University of Wyoming, for support of the research reported here. 2 Botany, Ohio State University, Columbus OH 43210. ' Biology, Texas A&M University, College Station TX 77843.

Numerical analysis of the scarlet oak complex (Quercus subgen. Erythrobalanus) in the eastern United states: relationships above the species level

Abstract: Seven species, representing three generally accepted series, of Quercus subgen Erythrobalanus were subjected to numerical analyses. Results from principle coordinate analysis followed by nonmetric mul

Flavonoid Analysis of Hybridization in Rhododendron Section Pentanthera (Ericaceae)

Abstract: Rhododendron canescens and R. austrinum differ markedly in flavonoid profiles but have identical flowering times and occupy similar habitats. Flower color is the most reliable visible feature distinguishing these species. Analysis of experimental and putative hybrids between these species indicates a possible regulatory instability of flavonoid synthesis. In contrast, R. canescens and R. speciosum differ in chemistry, morphology, flowering time, and habitat. The variation of flavonoids detected in R. canescens X R. speciosum hybrids could be attributed to gene segregation and recombination. The taxonomic difficulty of Rhododendron section Pentanthera (azaleas) has been stressed by Rehder (1921), Wherry (1943), and Skinner (1961). Millais (1924), Skinner (1955, 1961), and Galle (1967) reported natural hybridization in some 18 different combinations, several involving as many as three species. Species of section Pentanthera are often only ecologically or seasonally isolated. Skinner (1961) suggested that hybridization and presumably introgression are to be expected whenever synchronous flowering species of azaleas are sympatric. Despite the numerous reports of hybrids, however, little or nothing is known of the population structure of the hybrid swarms or of their evolutionary significance. As Jones (1967) has stated, the consequences of natural hybridization must be considered on two levels: 1) the immediate effects and 2) the long-term result, expressed as a breakdown of isolating mechanisms and permanent alterations in the variation pattern. Morphological analysis of hybrid populations in section Pentanthera is frequently difficult because of the relatively few key characters distinguishing many species. Cytological approaches have contributed little to understanding the population structure of hybrid swarms (e.g., Sax, 1930; Li, 1957). Cytological examination of experimental hybrids and putative hybrid clones indicated complete or nearly complete bivalent formation at meiosis and essentially normal pollen stainability in crosses between diploids. It was hoped, therefore, that flavonoids could be used for the analysis of natural hybridization among these azaleas. The work reported here represented a 1 This research was supported by National Science Foundation Grant GB-35480, by a grant from the Ida Cason Callaway Foundation, and by the University of Georgia. I thank S. B. Jones, T. J. MVabry, Z. Abdel-Baset, L. Urbatsch, and F. C. Galle for assistance and advice. This paper is based on a dissertation submitted in partial fulfillment of the requirements for the Ph.D. degree in the Department of Botany of the University of Georgia. 2 Biology, Randolph-Macon College, Ashland VA 23005. This content downloaded from 157.55.39.195 on Thu, 14 Apr 2016 07:02:32 UTC All use subject to http://about.jstor.org/terms 1977] KING: FLAVONOIDS AND HYBRIDS IN RHODODENDRON 15 smaller part of a broader chemotaxonomic investigation of section Pentanthera in which 58 leaf flavonoids distributed among 17 species were characterized (King, 1975; King et al., 1975; Mabry et al., 1975; King, 1977). The specific objectives of the hybridization study were to characterize the leaf flavonoids of selected experimental hybrids and their parental species and to utilize flavonoid data in the analysis of natural hybrid populations. Synthetic hybrids are seldom available for systematic studies of woody plants, but for this work experimental hybrids were available at Callaway Gardens, Pine Mountain, Georgia. This collection was developed by Mr. Fred Galle, who began an extensive hybridization program in 1954 among the native azaleas and successfully produced many hybrids. After preliminary work, R. canescens (Michaux) Sweet, R. austrinum (Small) Rehder, and R. speciosum (Willdenow) Sweet were selected for hybridization studies because 1) natural hybrids had been reported between R. canescens and R. austrinum and between R. canescens and R. speciosum, 2) the locations of these hybrid swarms had been reported, and 3) experimental hybrids were available at Callaway Gardens. MATERIALS AND METHODS Voucher specimens of the Rhododendron species and hybrids studied were collected at the time of flowering and deposited in GA. When the vouchers were collected, each plant was marked with an aluminum label and numbered. The plants were later revisited and mature leaf samples (100150 g) taken and dried. Extraction, isolation, purification, and identification of leaf flavonoids followed the methods of Mabry et al. (1970) and AbdelBaset (1973). The general procedure included 1) extraction of ca. 150 g of finely ground leaves with chloroform followed by neutral methanol, 2) initial examination of chloroform and methanol extracts for the presence of flavonoids by polyamide thin-layer chromatography and two-dimensional paper chromatography, and 3) separation and purification of compounds by column (Sephadex LH-20, Polyclar) and paper chromatography. Each purified compound was identified by some or all of the following procedures: Rf values, color reactions under UV and UV/NH3 vapor, UV spectral analysis, NMR spectra, enzyme or acid hydrolysis, and co-chromatography with authentic samples. Samples of 15 populations throughout the range of R. canescens and five populations of R. austrinum were analyzed to establish flavonoid profiles. The small number of populations of R. austrinum examined reflects the limited distribution of this species. Analysis of R. speciosum was limited to plants growing at Callaway Gardens. Only one putative hybrid swarm of Rhododendron canescens X R. austrinurn and one of R. canescens X R. speciosum were located. Leaf material from the hybrid swarms and from experimental hybrids between these species was obtained and analyzed for flavonoids. The authentic parents of the experimental hybrids could not be located. Inasmuch as spectral data for compounds detected in section This content downloaded from 157.55.39.195 on Thu, 14 Apr 2016 07:02:32 UTC All use subject to http://about.jstor.org/terms 16 SYSTEMATIC BOTANY [Volume 2 Pentanthera have been reported elsewhere (King, 1975; Mabry et al., 1975; King, 1977, they are not given here. The origins of collections, identified by accession number, and the number (N) of plants tested were: 6, 7. R. canescens (N = 2). Callaway COVINGTON Co.: Between Lake Gardens. Gantt and railroad, US 29 N of 1 1. R. speciosum (N 1). Callaway Clearview. Gardens. 86. R. austrinum (N = 6). ALABAMA. 19. R. austrinum x R. canescens (N COVINGTON Co.: 1 mi. N of Clear2). Callaway Gardens. view, US 29. 30. R. speciosutm (N = 1). Callaway 87. R. austrinum (N = 1). ALABAMA. Gardens. ESCAMBIA Co.: 1 mi. N of Conecuh 39. R. canescens (N = 1). Callaway GarRiver, US 29. dens. 88. R. austrinum (N = 10). ALABAMA. 44-47. R. austrinum (N = 4). Callaway ESCAMBIA Co.: 0.7 mi. N of East Gardens. Brewton, US 29. 62. R. speciosum (N = 1). Callaway 89. R. canescens (N = 10). Mississippi. Gardens. GEORGE Co.: 1 mi. W of Pasgua68. R. speciosum X R. capescens (N goula River, US 26. 3). Callaway Gardens. 90. R. canescens (N = 5). Mississippi. 76. R. canescens (N = 5). GEORGIA. JONES Co.: 0.3 mi. N of EstaHARRIS Co.: Entrance to Roosebutchie, county road off US 11. velt State Park. 92. R. canescens (N = 10). LoUISIANA. 78. R. canescens (N = 10). SOUTH CAROBEAUREGARD PARRISH: 2.4 mi. E LINA. ALLENDALE Co.: Between of Sabine River, US 90. Fairfax and Brunson, E of junc93. R. canescens (N = 10). ARKANSAS. tion of US 278 and 321. CALHOUN Co.: Champanolle Road 80. R. canescens (N 10). GEORGIA. exit from US 167N. TIFT CO.: 1 mi. W of TyTy. 94. R. canescens (N = 10). Mississippi. 81-1. R. austrinutm (N 2). FLORIDA. ITWAMBA Co.: 3 mi. E of Tremont WALTON Co.: Hwy. 2, 10 mi. S of on US 78. junction with US 81. 97. R. canescens (N = 10). ALABAMA. 81-2. R. attstrinum (N = 2). FLORIDA. WINSTON Co.: 8.9 mi. N of Double HOLMES Co.: Hwy. 2, 2 mi. S of Springs, US 278. junction with US 81. 98. R. canescens (N = 10). ALABAMA. 82. R. canescens (N = 10). ALABAMA. ST. CLAIR Co.: 4 mi. S of Asheville, GENEVA Co.: 6 mi. N of junction US 23 1. of Hwy. 27 and US 85. 99. R. canescens (N = 5). GEORGIA. 83. R. austrinum (N = 5). ALABAMA. CLARKE Co.: Near fire tower, ColGENEVA Co.: 5 mi. N of junction lege Station Road, Athens. of Hwy. 27 and US 85. 101. R. canescens x R. austrinum (N 84. R. austrinum (N = 5). ALABAMA. 1). Callaway Gardens. COVINGTON Co.: US Hwy. 55, 1-5 103. R. speciosum X R. canescens (hybrid mi. S of Andalusia. swarm), (N = 20). GEORGIA. UP85. R. austrinum X R. canescens (hybrid SON Co.: Near Camp Thunder and swarm), (N 18). ALABAMA. Flint River, Woodbury.

Chromosomes of the Independently Reproducing Appalachian Gametophyte: A New Source of Taxonomic Evidence

Abstract: A recently developed technique has provided the first chromosome counts for fern gametophytic populations that reproduce and develop geographic ranges independently of a sporophytic generation. The "Appalachian gametophyte" is now known to be a tetraploid (n 120). Sporophytes of Vittaria lineata, the species to which the Appalachian gametophyte is now generally referred, are octoploid (2n 240) whereas those of V. graminifolia, the only other vittarioid species reported from the continental United States, are tetraploid (2n 120). The cytological data available thus far support the previously advanced hypothesis that the Appalachian gametophyte is conspecific with or derived from V. lineata. Populations of fern gametophytes that reproduce and presumably spread independently of their sporophytes in the eastern United States have been known for many years (Wherry, 1942), but only relatively recently have significant efforts been made to identify them to genus or species (Wagner 8c Sharp, 1963; Wagner 8c Evers, 1963; Farrar, 1967). Such gametophytes are now attributed to four genera-Vittaria, Hymenophyllum, Trichomanes, and Grammitis-based on various morphological criteria (Farrar, 1967). The most famous of these is the "Appalachian gametophyte," at first considered to be a species of the filmy fern genus Hymenophyllum (Wherry, 1942) but more recently interpreted as the gametophyte of the Shoestring Fern, Vittaria lineata (Linnaeus) J. E. Smith, or a closely related species (Wagner 8c Sharp, 1963). Vittaria lineata has a normal alternation of sporophytic and gametophytic generations in Florida and in the American tropics, but its gametophytes have long been recognized as capable of reproducing independently of the sporophytes in these regions by means of spindle-shaped gemmae produced along the margins of the ribbon-like thallus (Britton 8c Taylor, 1902). The Appalachian gametophyte, however, occurs over a large region of the eastern United States in an extensive geographic range well beyond that of any associated sporophyte generation. Renewed interest in this gametophyte was generated by its recent discovery in a sandstone cliff grotto between Tazwell and Mifflin in Crawford County, Indiana (Gastony 1102, GH, IND, us). This is the first published record of this species for the state, extending its known range to the northwest from Kentucky and Ohio. It has recently been learned, however, that 1 J thank Ranger John W. Moore for help in obtaining the Appalachian gametophyte in the Daniel Boone National Forest, Robert WT. Long for providing sporophytic material of Vittaria lineata, and Christopher H. Haufler for advice and discussion. 2 Biology, Indiana University, Bloomington IN 47401. This content downloaded from 157.55.39.113 on Wed, 14 Dec 2016 04:56:59 UTC All use subject to http://about.jstor.org/terms 44 SYSTEMATIC BOTANY [Volume 2 this gametophyte was previously collected in Crawford County several miles to the south of the above location at a site noted in an unpublished thesis (Farrar, 1971). In view of the general use of chemotaxonomic and cytotaxonomic methods in elucidating cryptic relationships among plant species, it is remarkable that such methods have not been brought to bear on the specific identities of independently reproducing fern gametophytes. Chromosome numbers in particular have been extensively used along with meiotic pairing behavior and even karyotype analysis to clarify taxonomic affinities in the ferns (Walker, 1973), but such data have not yet been used to aid in establishing the identities of these gametophytes. The relatively rare instances in which gametophytic chromosomes have been examined appear to be restricted to studies of apomixis, apospory, endopolyploidy, or the morphological and physiological effects of a polyploid series (examples: Lawton, 1932; Partanen et al., 1955; Partanen, 1961; Whittier, 1966, 1970). The first use of gametophytic chromosomes to provide taxonomic data appears to have been in a recent analysis of the genus Bommeria (Gastony 8c Haufler, 1976). In that study a simple method of preparing gametophyte chromosome squashes was developed by modifying a root-tip technique of Roy and Manton (1965). This technique employs snail cytase (now obtained in prepared form as "Glusulase" from Endo Laboratories, Garden City NY) to digest cell walls and thus allows excellent spreads of mitotic figures even where large chromosome numbers are involved. Whole gametophytes were prepared for squashing by placing them in the snail cytase at room temperature for 2.5-3 hours. Following the final fixation, the meristematic areas of the gametophytes were excised and only these areas were stained and squashed. A major purpose of this paper is to call attention to this technique's potential for opening a new approach to research in gametophyte population biology in general and into the identities and origins of these independently reproducing gametophytic taxa in particular. Through the use of this technique, the chromosome number of the Appalachian gametophyte is reported here for the first time as n 120 (Fig. 1, 2), based on Gastony 1101 from Kentucky (see appendix). Earlier published efforts to determine the probable evolutionary affinities of this gametophyte were based exclusively on morphological evidence and have led to the conclusion that it may be 1) a taxonomic variety of Vittaria lineata in which the sporophytic phase has been lost from the life cycle, 2) the derivative of a related species now extinct, or 3) the derivative of some other species of Vittaria or of a closely allied genus (Wagner 8c Sharp, 1963; Wagner 8c Evers, 1963; Farrar, 1967). Perhaps more remarkable than the previous lack of chromosome counts for the Appalachian gametophyte is the lack of such information for the sporophytes of V. lineata with which it has been associated-particularly since V. lineata is fairly common in parts of Florida. The chromosome number of V. lineata is reported here for the first time as 2n 240 (Fig. 3, This content downloaded from 157.55.39.113 on Wed, 14 Dec 2016 04:56:59 UTC All use subject to http://about.jstor.org/terms 1977] GASTONY: CHROMOSONMES OF THE APPALACHIAN GAMETOPHYTE 45

New Data on Chromosome Numbers in Aster Section Heterophylli (Asteraceae) and Their Phylogenetic Implications

Abstract: Reports suggesting that the basic chromosome numberfor Aster section Heterophylli is x = 9 have been cited to support the hypothesis that x = 9 is the ancestral basic number for the whole genus. The present report gives chromosome counts for 35 populations in ten species, nine of which are traditionally placed in section Heterophylli. The chromosome numbers in 33 populations present a polyploid series of n = 8, 16, 24, and 32. Reinterpretation of photomicrographs by Avers (1954) lends additional support to the finding that the basic number for the section is x = 8 rather than x = 9. If counts for the three species not yet re-examined agree with these results, the balance between species of the x = 8 and x = 9 groups will be significantly shifted, and phylogenetic considerations based on the number of species belonging in each of the three "modes" (x = 5, 8, and 9) in the genus must be reassessed. Inasmuch as all Old World species of Aster exhibit x = 9, this group remains the largest on a worldwide basis, but with the inclusion of section Heterophylli, the x = 8 group comprises the largest number of species in North America, the generally acknowledged center of origin for the genus. The presentfindings are interpreted as supporting the hypothesis that evolution proceeded from the low basic chromosome number of x = 4 or 5 rather than the high one of x = 9. Aster is one of the relatively few members of the tribe Astereae that exhibits more than one mode of chromosome numbers, namely x = 5, 8, and 9. Several publications dealing with the phylogeny of the tribe are concerned with the question of which of the basic chromosome numbers is primitive, the high x = 9 or the low x = 4 or 5. Authors in favor of the hypothesis that the high number is ancestral (Huziwara, 1959, 1967; Raven et al., 1960; Solbrig, 1967; Solbrig et al., 1964, 1969) point out that the majority of species have the base number of x = 9 whereas x = 5 is found in a much smaller number of rather heterogeneous species adapted to arid regions and saline habitats. They reason further that the high base number is usually correlated with some other characteristics considered primitive in the Asteraceae, such as perennial and often somewhat woody habit and a high degree of polyploidy. In the view of these authors, Aster species with x = 5 chromosomes have been derived through successive aneuploid loss and subsequent catastrophic extinction of the less successful intermediate types-i.e., taxa with x = 6 or 7. The opposite stand is taken by Turner et al. (1961), who reason that 1I thank Christine A. Newell for checking some of my chromosome counts. 2 Botany, University of Illinois at Urbana-Champaign, Urbana IL 61801.

The American species of Nesaea (Lythraceae) and their relationships to Heimia and Decodon.

Abstract: Three species of the primarily African genus Nesaea occur in the New World. One, N. palmeri, is described as new. The presence of the genus in North America has been obscured by its rarity and by an erroneous placement of the most widely distributed species, N. longipes, in the closely related genus Heimia. Morphological comparisons of Nesaea, Heimia, and Decodon-genera once included in Nesaea-confirm the distinctiveness of these genera and the correct placement of N. longipes. Nesaea consists of approximately 45 species, three-fourths of which are restricted to Africa and Madagascar. The remainder occur in Africa, southern Asia, the East Indies, Australia, and North America. Three species of Nesaea are now known from the New World, where their presence has been obscured by their rarity and by erroneous placement of the most widely distributed American species, N. longipes A. Gray, in the closely related genus Heimia. Heimia longipes (A. Gray) Cory is a gypsophilous, calciphilous species of New Mexico, Texas, and adjacent Coahuila, Mexico. It differs conspicuously in habit and morphology from the other two species of this genus. Heimia longipes is a sprawling herbaceous perennial with pink to purple petals. Heimia salicifolia Link and H. myrtifolia Chamisso & Schlectendal are shrubs to three meters tall with yellow-petaled flowers. Although herbaceous and shrubby species occur within other genera of the Lythraceae, no genera are known in the family that have purpleand yellow-petaled species. The differences in pollen morphology of H. longipes, H. salicifolia, and H. myrtifolia are equally striking. It was, in fact, the anomalous pollen of H. longipes that precipitated this study. The pollen of H. longipes is unlike that of the other species of Heimia but is characteristic of that of Nesaea. Since all the genera of Lythraceae probably have a distinctive pollen morphology, H. Iongipes appears, on the basis of pollen characters as well as floral and vegetative features, to be misassigned. Originally Nesaea also included Heimia, Decodon, and Diplusodon. Heimia and Decodon were retained within Nesaea as subgenera or sections 1 J thank Alan Graham for assistance in preparation and interpretation of the pollen; Joan Nowicke for Fig. 1-3, 6, and 7; J. Rzedowski, D. Ott, F. Potter, B. Tiffney, J. Timmerman, M. Johnston, and D. Pinkava for advice; the Department of Polymer Science, University of Akron, for use of SEM facilities; Lynn Miller for the drawings; and Marshall Johnston for reviewing the manuscript. 2 c/o Alan Graham, Biological Sciences, Kent State University, Kent OH 44242. This content downloaded from 40.77.167.32 on Sun, 04 Sep 2016 04:45:14 UTC All use subject to http://about.jstor.org/terms 62 SYSTEMATIC BOTANY [Volume 2