http://amborella.net/2010PlantSystematics/DATA/3-24-APG%202003%20Bot%20J%20Linn%20Soc%20APGII.pdf

An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II

Angiosperm phylogeny inferred from 18S rDNA, rbcL, and atpB sequences

The great taxonomic diversity of the Orchidaceae is often attributed to adaptive radiation for specific pollinators driven by selection for outcrossing. However, when one looks beyond the product to the process, the evidence for selection is less than overwhelming. We explore this problem by discussing relevant aspects of orchid biology and asking which aspects of reproduction explain the intricate pollination mechanisms and diversification of this family. We reaffirm that orchids are primarily pollination limited, the severity of which is affected by resource constraints. Fruit set is higher in temperate than in tropical species, and in species which offer pollinator rewards than those that do not. Reproductive success is skewed towards few individuals in a population and effective population sizes are often small. Population structure, reproductive success and gene flow among populations suggest that in many situations genetic drift may be as important as selection in fostering genetic and morphological variation in this family. Although there is some evidence for a gradualist model of evolutionary change, we believe that the great diversity in this family is largely a consequence of sequential and rapid interplay between drift and natural selection. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 84, 1–54.

Variation in sexual reproduction in orchids and its evolutionary consequences: a spasmodic journey to diversification

The orchid family is renowned for its enormous diversity of pollination mechanisms and unusually high occurrence of non-rewarding flowers compared to other plant families. The mechanisms of deception in orchids include generalized food deception, food-deceptive floral mimicry, brood-site imitation, shelter imitation, pseudoantagonism, rendezvous attraction and sexual deception. Generalized food deception is the most common mechanism (reported in 38 genera) followed by sexual deception (18 genera). Floral deception in orchids has been intensively studied since Darwin, but the evolution of non-rewarding flowers still presents a major puzzle for evolutionary biology. The two principal hypotheses as to how deception could increase fitness in plants are (i) reallocation of resources associated with reward production to flowering and seed production, and (ii) higher levels of cross-pollination due to pollinators visiting fewer flowers on non-rewarding plants, resulting in more outcrossed progeny and more efficient pollen export. Biologists have also tried to explain why deception is overrepresented in the orchid family. These explanations include: (i) efficient removal and deposition of pollinaria from orchid flowers in a single pollinator visit, thus obviating the need for rewards to entice multiple visits from pollinators; (ii) efficient transport of orchid pollen, thus requiring less reward-induced pollinator constancy; (iii) low-density populations in many orchids, thus limiting the learning of associations of floral phenotypes and rewards by pollinators; (iv) packaging of pollen in pollinaria with limited carry-over from flower to flower, thus increasing the risks of geitonogamous self-pollination when pollinators visit many flowers on rewarding plants. All of these general and orchid-specific hypotheses are difficult to reconcile with the well-established pattern for rewardlessness to result in low pollinator visitation rates and consequently low levels of fruit production. Arguments that deception evolves because rewards are costly are particularly problematic in that small amounts of nectar are unlikely to have a significant effect on the energy budget of orchids, and because reproduction in orchids is often severely pollen-, rather than resource-limited. Several recent experimental studies have shown that deception promotes cross-pollination, but it remains unknown whether actual outcrossing rates are generally higher in deceptive orchids. Our review of the literature shows that there is currently no evidence that deceptive orchids carry higher levels of genetic load (an indirect measure of outcrossing rate) than their rewarding counterparts. Cross-pollination does, however, result in dramatic increases in seed quality in almost all orchids and has the potential to increase pollen export (by reducing pollen discounting). We suggest that floral deception is particularly beneficial, because of its promotion of outcrossing, when pollinators are abundant, but that when pollinators are consistently rare, selection may favour a nectar reward or a shift to autopollination. Given that nectar-rewardlessness is likely to have been the ancestral condition in orchids and yet is evolutionarily labile, more attention will need to be given to explanations as to why deception constitutes an 'evolutionarily stable strategy'.

Mechanisms and evolution of deceptive pollination in orchids

Many flowers produce rewards, usually nectar or pollen or both. C. K. Sprengel (165), the founder of modern floral biology, was the first to report that flowers do not always reward pollinators; his observations were on the genus Orchis. Subsequent authors (7; 51; 66; 97; 99; 105; 186, p. 21; 195) have discussed various aspects of deceitful flowers that attract pollinators by resembling rewarding flowers or other objects.

Mimicry and Deception in Pollination

Sequence data for plastid rbcL and atpB from members of Anacardiaceae, Burseraceae, Cneoraceae, Meliaceae, Ptaeroxylaceae, Rutaceae, and Simaroubaceae were analyzed cladistically to evaluate the familial and subfamilial circumscriptions of Rutaceae. Taxa representing all subfamilies and tribes were sampled. The analysis shows that Rutaceae are paraphyletic, with Spathelia and Dictyoloma (Rutaceae), Harrisonia (Simaroubaceae), Cneorum (Cneoraceae), and Ptaeroxylon (Ptaeroxylaceae) forming a clade sister to all other Rutaceae. Circumscription of Rutaceae to include all of these taxa is recommended. This analysis indicates that Simaroubaceae and Meliaceae are the outgroups closest to Rutaceae. Correlation of the molecular phylogenies with biochemical data indicates that chemotaxonomic information is more reliable than fruit type as an indicator of familial and subfamilial circumscriptions. The subfamilial classification needs revision; none of the subfamilies of more than one genus is monophyletic.

Phylogenetic relationships of Rutaceae: a cladistic analysis of the subfamilies using evidence from RBC and ATP sequence variation

Primarily known only by the edible fruits of Citrus, Rutaceae comprise a large (c. 160 genera and 1900 species), morphologically diverse, cosmopolitan family. Of its extraordinary array of secondary chemical compounds, many have medicinal, antimicrobial, insecticidal, or herbicidal properties. To assist with the much-needed suprageneric reclassification and with studies of evolution of chemical compounds and biogeographic history of the family, here we included sequence data (from two noncoding regions of the chloroplast genome-rps16 intron and trnL-trnF region) from 65 species in 59 genera (more than one third of those in the family) that represented all subfamilies and tribes and more genera of Toddalioideae and of neotropical groups than previous studies. Results confirmed that Cneorum, Ptaeroxylon, Spathelia, and Dictyoloma form a clade sister to the remaining Rutaceae, none of the subfamilies with more than one genus (except Aurantioideae) is monophyletic, and characters of the ovary and fruit are not reliable for circumscription of subfamilies. Furthermore, clades are better correlated with geographic distributions of the genera than with ovary and fruit characters. Circumscriptions of subfamilies and tribes (and some subtribes of Rutoideae) must be reevaluated. Results are discussed in light of geographic distributions, caryology, chemotaxonomy, and other molecular studies.

https://bsapubs.onlinelibrary.wiley.com/doi/pdf/10.3732/ajb.2007313

Phylogeny of Rutaceae based on twononcoding regions from cpDNA

The position of the plant genus Pitavia within an infrafamilial phylogeny of Rutaceae (rue, or orange family) was investigated with the use of two non-coding regions from cpDNA, the trnL-trnF region and the rps16 intron. The only species of the genus, Pitavia punctata Molina, is restricted to the temperate forests of the Coastal Cordillera of Central-Southern Chile and threatened by loss of habitat. The genus traditionally has been treated as part of tribe Zanthoxyleae (subfamily Rutoideae) where it constitutes the monogeneric tribe Pitaviinae. This tribe and genus are characterized by fruits of 1 to 4 fleshy drupelets, unlike the dehiscent fruits typical of the subfamily. Fifty-five taxa of Rutaceae, representing 53 genera (nearly one-third of those in the family) and all subfamilies, tribes, and almost all subtribes of the family were included. Parsimony and Bayesian inference were used to infer the phylogeny; six taxa of Meliaceae, Sapindaceae, and Simaroubaceae, all members of Sapindales, were also used as out-groups. Results from both analyses were congruent and showed Pitavia as sister to Flindersia and Lunasia, both genera with species scattered through Australia, Philippines, Moluccas, New Guinea and the Malayan region, and phylogenetically far from other Neotropical Rutaceae, such as the Galipeinae (Galipeeae, Rutoideae) and Pteleinae (Toddalieae, former Toddalioideae). Additionally, a new circumscription of the subfamilies of Rutaceae is presented and discussed. Only two subfamilies (both monophyletic) are recognized: Cneoroideae (including Dictyolomatoideae, Spathelioideae, Cneoraceae, and Ptaeroxylaceae) and Rutoideae (including not only traditional Rutoideae but also Aurantioideae, Flindersioideae, and Toddalioideae). As a consequence, Aurantioideae (Citrus and allies) is reduced to tribal rank as Aurantieae.

https://phytokeys.pensoft.net/lib/ajax_srv/article_elements_srv.php?action=download_pdf&item_id=1452

Chilean Pitavia more closely related to Oceania and Old World Rutaceae than to Neotropical groups: evidence from two cpDNA non-coding regions, with a new subfamilial classification of the family

Angostura Roem. & Schult. as understood by Engler is defined more narrowly here. The species excluded from Angostura are recognized as species of ConchocarpusJ. C. Mikan. Three new species of Angostura (A. alipes Kallunki from Ecuador, A. quinquefolia Kallunki from Pari and Maranhao, Brazil, and A. simplex Kallunki from western Amazonas, Brazil, and San Martin, Peru) are described, and three new combinations in this genus are made. In Conchocarpus, 24 new combinations are made, and the following 21 new taxa are described: C. bellus Kallunki, C. cauliflorus Pirani, C. concinnus Kallunki, C. cuneifolius var. confertus Kallunki, C. cyrtanthus Kallunki, C. dasyanthus Kallunki, C. diadematus Pirani, C. fissicalyx Pirani, C. furcatus Kallunki, C. gaudichaudianus subsp. bahiensis Kallunki, C. grandis Kallunki, C. hirsutus Pirani, C. inopinatus Pirani, C. insignis Pirani, C. longipes Kallunki, C. mastigophorus Kallunki, C. modestus Kallunki, C. oppositifolius Kallunki, C. punctatus Kallunki, C. santosii Pirani & Kallunki, and C. sordidus Kallunki. With the exception of C. grandis from Amazonian Brazil, all are native to the coastal forests of eastern Brazil. As a result, seven species of Angostura and 45 of Conchocarpus are recognized. Keys to the taxa of both genera are provided. Lectotypes are designated for Cusparia grandiflora Engl., C. macrocarpa Engl., C. paniculata Engl., C. toxicaria Engl., Galipea odoratissima Lindl., and Lasiostemum silvestre Nees & Mart. and an epitype for Galipea elegans A. St.-Hil. The new combination, Rauia nodosa (Engl.) Kallunki, is made for Cusparia nodosa. The tribe Cusparieae DC. and subtribe Cuspariinae Engl., based on the illegitimate generic name Cusparia Humb., are renamed Galipeeae Kallunki and Galipeinae Kallunki.

Jacquelyn A. Kallunki

Papers

Phylogenetic relationships of Rutaceae: a cladistic analysis of the subfamilies using evidence from RBC and ATP sequence variation

Phylogeny of Rutaceae based on twononcoding regions from cpDNA

Chilean Pitavia more closely related to Oceania and Old World Rutaceae than to Neotropical groups: evidence from two cpDNA non-coding regions, with a new subfamilial classification of the family

Synopses of Angostura Roem. & Schult. and Conchocarpus J. C. Mikan (Rutaceae)

Michigan Flora, Part II, Dicots (Saururaceae-Cornaceae)