Joan W. Nowicke

Bio: Joan W. Nowicke is an academic researcher from Smithsonian Institution. The author has contributed to research in topics: Pollen & Acalyphoideae. The author has an hindex of 24, co-authored 48 publications receiving 1379 citations. Previous affiliations of Joan W. Nowicke include National Museum of Natural History & University of Missouri–St. Louis.

Pollen Morphology in the Order Centrospermae

Abstract: Pollen of 190 species from 16 families has been examined by light and scanning electron microscopy. Three basic pollen types were found: 3-colpate, pantoporate, and pantocolpate, all with a spinulose and tubuliferous/punctate ektexine. The palynological data emphasize the close relationship of the betalain families, and support their association with the anthocyanin families. Caryophyllaceae and Molluginaceae. Pollen morphology reinforces the placement of the Cactaceae and Didiereaceae in the order, and would support the inclusion of Dysphania in the Chenopodiaceae. The pollen grains of the Achatocarpaceae, Bataceae, Gyrostemonaceae and Theligonaceae, none of which had the spinulose and tubuliferous/punctate ektexine, had no counterparts in the remaining taxa examined. Thus, the evidence from palynology does not support their inclusion in the Centrospermae and indicates that their placement should be re-examined.

Ultrastructure of pollen exine in centrospermous families

Abstract: Transmission electron microscopy was utilized to examine pollen walls of selected taxa in theAizoaceae, Amaranthaceae, Basellaceae, Cactaceae, Chenopodiaceae, Didiereaceae, Halophytaceae, Nyctaginaceae, Phytolaccaceae, Portulacaceae, andCaryophyllaceae. This conspectus is an adjunct to scanning electron microscope observations of pollen surfaces and is directed towards elucidating the basic wall structure for these families. Although differences in internal morphology were observed at the inter- and intra-familial levels, they were interpreted as reflecting variations rather than major differences. The data indicate close morphological similarities of the first ten families enumerated above, i.e., those containing betalains. TheCaryophyllaceae, an anthocyanin family, indicated a slightly greater heterogeneity of pollen ultrastructure but not to the extent of disassociating it from the betalain families. In fact, this heterogeneity was rivaled by comparable heterogeneity among and within some of the betalain families. The conclusion is that all families have close pollen morphological relationships.

A Palynological Study of Crotonoideae (Euphorbiaceae)

Abstract: Pollen of 69 species representing 34 genera from 12 of the 13 tribes of Crotonoideae sensu Webster was examined in light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The pollen of the vast majority of the subfamily is inaperturate, and all Crotonoideae exines have a similar architecture: triangular supratectal elements attached to a network of muri having short or irregular columellae. These three components, triangular supratectal elements, muri, and modified columellae constitute the Croton structure. The triangular elements, designated subunits, can be psilate, striate, furrowed and ridged, or pitted, and with echinate, rounded, or long-attenuate apices; the subunits can be closely spaced or arrayed in more open configurations. A Croton sculpture refers to the presence of triangular sculpture elements, which may or may not have muri and modified columellae. Inaperturate grains have thin footlayers and thin endexines, whereas colpate pollen bas both footlayer and endexine well developed; in porate grains, the footlayer and endexine appear intermediate between inaperturate and colpate. Tribes Micrandreae (Hevea, Micrandra, Micrandropsis examined) and Adenoclineae (Adenocline, Ditta, Glycydendron, Endospermum, Klaineanthus, Tetrorchidium) are 3-colpate and probably primitive, having retained not only apertures but (prominent) footlayers and endexines as well; Manihoteae (Manihot, Cnidoscolus examined) and Gelonieae (Suregada) are porate. The thicker aperturate exines, especially in the colpate grains, may be linked with retention of apertures. The remaining 22 genera examined, including the two largest, Croton and Jatropha, have inaperturate pollen. A thin footlayer/endexine also occurs in Oldfieldioideae, and a tectum with triangular elements is found in some Acalyphoideae. In both morphology and exine structure, the pollen of Crotonoideae closely resembles the (porate) pollen of Thymelaeaceae.

Pollen ultrastructure of Panax(the ginseng genus, Araliaceae),an eastern Asian and eastern NorthAmerican disjunct genus

Abstract: Pollen of ten species of Panax and six species of Aralia was examined in light microscopy and scanning and transmission electron microscopy. Grains of both genera have similar complex apertures, short columellae, and overlapping tectal sculptures, suggesting a close relationship. Most species of Panax have pollen characterized by striato-reticulate tecta, short columellae, thick foot layers, costa ectocolpi, and lalongate endoapertures. The eastern North American P. trifolius, commonly known as the dwarf ginseng, has a distinctive pollen morphology and exine structure, supporting the hypothesis of its phylogenetically isolated position. Pollen of the eastern Asian P. ginseng (ginseng) can be distinguished from the eastern North American P. quinquefolius (American ginseng) by differences in ultrastructure. The monophyly of the three medicinally important species, P. ginseng, P. notoginseng, and P. quinquefolius, suggested by triterpenoid data, is not supported by pollen data. The results of the pollen study are generally congruent with those from the sequences of nuclear ribosomal DNA.

Fossil pollen records of extant angiosperms.

Abstract: The fossil record for angiosperm pollen types which are comparable to recent taxa is evaluated, following a similar survey published in 1970. Special attention is paid to the dating of the sediments. Evidence for 139 families is considered to be reliable, for others the records are cited as provisional, pending the accumulation of more evidence. Some published records are shown to be erroneous.

Molecular Systematics of Plants

Abstract: Preface. Part I: Molecules and genomes in plant systematics. Chloroplast DNA and the study of plant phylogeny: present status and future prospects - M T Clegg and G Zurawski Use of chloroplast DNA rearrangements in reconstructing plant phylogeny - S R Downie and J D Palmer Mitochondrial DNA in plant systematics: applications and limitations - J D Palmer Ribosomal RNA as a phylogenetic tool in plant systematics - R K Hamby and E A Zimmer Evolution of the NOR and 5S DNA loci in the Triticeae - R Appels and B Baum Part II: Molecular approaches to plant evolution Intraspecific chloroplast DNA variation: systematic and phylogenetic implications - D E Soltis, P S Soltis and B G Milligan Molecular data and polyploid evolution in plants - P S Soltis, J J Doyle and D E Soltis Molecular systematics and crop evolution - J Deobley Part III: Model studies of phylogenetic relationships Contributions of molecular data to polyploid evolution in plants - P S Soltis, J J Doyle and D E Soltis Molecular systematics and crop evolution - J Deobley Contributions of molecular data to papilionoid legume systematics - J J Doyle, M Levin and A Bruneau Chloroplast DNA variation in the asteraceae: phylogenetic and evolutionary implications - R K Jansen, H J Michaels, R S Wallace, K-J Kim, S C Keeley, L E Watson and J D Palmer Chloroplast DNA restriction site variation and the evolution of the annual habit in North American Coreopsis (Asteraceae) - D J Crawford, J D Palmer and M Kobayashi Molecular systematics of onagraceae: examples from Clarkia and Fuschia - K J Systema and J E Smith Floral morphology and chromosome number in the subtribe oncidiinae (Orchidaceae): evolutionary insights from a phylogenetic analysis of the chloroplast DNA restriction site variation - M W Chase and J D Palmer Part IV: Theoretical perspectives The suitability of molecular and morphological evidence in reconstructing plant phylogeny -M J Donaghue and M J Sanderson Character-site weighting for restriction site data in phylogenetic reconstruction, with an example from chloroplast DNA - V A Albert, B D Mishler and M W Chase Polymorphism, hybridization and variable evolutionary rate in molecular phylogenies - K Ritland and J E Eckenwalder Index.

Severely reduced sexual reproduction in northern populations of a clonal plant, Decodonverticillatus (Lythraceae)

Abstract: Summary 1 In flowering plants the balance between sexual and clonal, asexual reproduction can vary widely. We quantified variation in sexual reproduction in a tristylous, clonal, aquatic plant, Decodon verticillatus , and investigated the role of ecological and genetic factors in causing this variation. 2 We surveyed components of sexual fertility and vegetative growth in 28 populations distributed along a 500-km latitudinal transect in New England, USA. Northerly populations tend to be monomorphic (M) for style length, and probably therefore have reduced sexual reproduction compared with southerly, trimorphic (T) populations. 3 Compared with T populations ( n = 10), M populations ( n = 18) exhibited large reductions for all components of sexual reproduction, including flower production, pollen deposition, pollen tube growth, fertilization, fruit set and seeds per fruit. Seven M populations produced no seed at all, and the other 11 very little (mean = 24 vs. 1139 seeds per plant in trimorphic populations). Clonal propagation was also greatly reduced in M populations. 4 A survey of three polymorphic allozyme loci detected only single, usually heterozygous, genotypes in 15 M populations, whereas all T populations were genotypically diverse. The other three M populations contained three or fewer genotypes and one always predominated. Sexual recruitment is therefore extremely rare. 5 Comparison of the sexual fertility of M and T populations in a concurrent common glasshouse experiment with our field data revealed that reduced sexual performance in northern M populations is principally due to genetic factors, but is also caused by ecological factors that covary with latitude. 6 This abrupt shift away from sexual reproduction in populations at the northern periphery of the geographical range in D . verticillatus may greatly limit their evolutionary potential and restrict further northward expansion.

Classification and geography of the flowering plants

Abstract: Thome, Robert F. (Rancho Santa Ana Botanic Garden, Claremont, CA 91711). Classification and geography of the flowering plants. Bot. Rev.58(3): 225–348. 1992.—This treatment of the flowering plants is the latest revision of my classification of the Class Angiospermae and replaces my 1983 and more recent 1992 synopses. An update is necessary because so much new information has been published in the last decade pertinent to the classification of the flowering plants. About 870 such recent books, monographs, and other botanical papers are cited in the Introduction, listed primarily by the botanical discipline that they represent. Also considerable changes in my classification have been necessitated by my narrowed family- and ordinal-gap concepts, acceptance of the ending “-anae” for superorders in place of the traditional but inappropriate “-iflorae,” and acceptance of more prior or more widely used names for the categories above the family. A new phyletic “shrub” replaces earlier versions, and attempts to indicate visually relative sizes and relationships among the superorders, orders, and suborders. One table includes a statistical summary of floweringplant taxa: ca. 233,900 species of 12,650 genera, 437 families, and 708 subfamilies and undivided families in 28 superorders, 71 orders, and 71 suborders of Angiospermae. Three other tables summarize the known indigenous distribution of the families and subfamilies of angiosperms about the world. The synopsis lists the flowering plant taxa from the class down to the subfamily (and in Asteraceae down to the tribe) with indication of the degree of confidence I place in the circumscription and placement of each category above the subfamily, the best available estimates of the number of genera and species for each category, and the known indigenous distribution of each subfamily and family. Table V lists alphabetically the geographical abbreviations used in the synopsis. The extensive bibliography of recent literature should be helpful to those persons interested in the classification of the flowering plants.