Adiantopsis Fée (Pteridaceae) is a relatively unstudied tropical cheilanthoid fern genus. In the present work, we evaluated the taxonomy and relationships among Caribbean Adiantopsis by examining 136 characters from approximately 500 herbarium specimens. This study identified nine Caribbean Adiantopsis species, three of which are newly described (A. parvisegmenta, A. pentagona, and A. vincentii). Additionally, an intriguing pattern of morphological and reticulate evolution was revealed by the analyses. Adiantopsis consists of three different laminar morphologies; palmate, pedate, and pinnate. The two pedate taxa are hypothesized to be fertile allotetraploid derivatives of the palmate A. radiata (L.) Fée and two different pinnate taxa. In this regard they parallel the origin of the South American A. ×australopedata Hickey, M. S. Barker & Ponce. Based on our analyses, it appears that pedate laminar morphologies in Adiantopsis independently originated multiple times via hybridization. This study provides testable hypotheses of morphological and reticulate evolution in the genus and presents a novel view of Caribbean Adiantopsis.

Sequences of the plastid maturase (matK) and nuclear chalcone synthase (Chs) were analyzed separately and in combination to assess phylogenetic relationships of Solms-laubachia Muschl. (all nine known species and two undescribed ones) to the genera Baimashania Al-Shehbaz, Parrya R. Br., Desideria Pamp., Leiospora (C. A. Mey.) Dvořák, Christolea Cambess., and Phaeonychium O. E. Schulz (Brassicaceae). Baimashania is clustered with Aubrieta deltoidea (L.) DC. and Arabis blepharophylla Hook. & Arn. Solms-laubachia, Desideria, Leiospora, Christolea, and Phaeonychium are more closely related to Matthiola R. Br. than to Parrya, and they form a well-supported clade. Within this clade, Leiospora is sister to a subclade containing the sister groups Christolea and Solms-laubachia s.l. The Solms-laubachia s.l. group contains Solms-laubachia, Desideria, and a species of Phaeonychium. Neither Solms-laubachia nor Desideria is monophyletic, whereas Phaeonychium jafrii Al-Shehbaz is embedded within the group. Therefore, our results suggest that Solms-laubachia be expanded to include Desideria and P. jafrii. Nevertheless, more species of Desideria, Parrya, and Phaeonychium are needed to further test our findings.

A taxonomic revision of the genus Acaena in Chile was carried out, using morphological characters. Twenty species belonging to six sections are recognized for continental Chile and Juan Fernandez Archipelago. The most useful characters for recognizing species are inflorescence type, the form of leaflets, as well as the form and ornamentation of the fruit. The following species are lectotypified: A. alpina Poepp. ex Walp., A. caespitosa Gillies ex Hook. et Arn., A. integerrima Gillies ex Hook. et Arn., A. macrocephala Poepp., A. magellanica (Lam.) Vahl, A. pinnatifida Ruiz et Pav., A. platyacantha Speg., A. splendens Hook. et Arn., and A. tenera Alboff. The following species were neotypified: A. lucida (Aiton ) Vahl, A. sericea J. Jacq., and A. trifida Ruiz et Pav. var. glabrescens Regel et Körn. The following synonyms were lectotypified: A. argentea Ruiz et Pav. var. breviscapa Bitter, A. argentea Ruiz et Pav. var. coriacea Bitter, A. argentea Ruiz et Pav. var. interrupte-pinnata Bitter, A. argentea Ruiz et Pav. var. lanigera Bitter, A. argentea Ruiz et Pav. var. subcalvescens Bitter, A. cadilla Hook. f., A. canescens Phil., A. cuneata Hook. et Arn., A. digitata Phil., A. digitata Phil. var. latifoliolata Bitter, A. digitata Phil. var. subpinnata Bitter, A. euacantha Phil., A. fuegina Phil., A. glandulifera Bitter, A. grandistipula Bitter, A. hirsuta Phil., A. ischnostemon Bitter, A. krausei Phil., A. krausei Phil. subvar. glabratula Bitter, A. longiaristata H. Ross [= A. magellanica (Lam.) Vahl], A. lucida var. villosula Bitter, A. macrostemon Hook. f. subsp. longiaristata (H. Ross) Bitter var. basipilosa Bitter, A. macrostemon Hook. f., A. magellanica (Lam.) Vahl subsp. pygmaea Bitter, A. magellanica (Lam.) Vahl var. glabrescens Bitter, A. microcephala Schltdl., A. multifida Hook. f. subsp. intercedens Bitter, A. neglecta Bitter, A. petiolulata Phil., A. pinnatifida Ruiz e

Xeric limestone prairies (XLPs) are herbaceous plant communities that occur on shallow rocky calcareous soils from Missouri and Pennsylvania south to Arkansas and Georgia (U.S.A.). There has been considerable confusion regarding the classification of XLPs due to their similarity with limestone cedar glades (LCGs), an edaphic climax community type restricted to unglaciated southeastern United States. Although C₄ perennial grasses typically are the dominant taxa in XLPs, portions of sites with extremely shallow soils (≤ 0.1 m) are typified by local dominance of Sporobolus vaginiflorus (Torr. ex Gray) Alf. Wood, a C₄ summer annual grass that is the characteristic dominant in LCGs. In this study, we assess the relative importance of C₄ perennial grasses versus S. vaginiflorus in XLP community types identified in Kentucky over a range of scales. We then use these data to analyze variability in XLP vegetation and physical environmental conditions and to further compare XLPs with LCGs. Sporobolus vaginiflorus had high frequencies in many of the fine-scale community types (0.01 and 0.1 m²) identified in this study. However, dominance of C₄ perennial grasses (particularly Schizachyrium scoparium (Michx.) Nash) in all 12 of the community types identified at the largest scale (100 m²) is indicative of the relatively small areal extent of extremely shallow-soiled regions in XLPs. XLPs also differ from LCGs in that the former generally lack early-stage primary successional community types dominated by cryptograms and/or C₃ annual forbs. Thus, the results of our study suggest that the total range of environmental conditions and the variety and extent of plant community types present in a site should be considered when classifying the vegetation of calcareous rock outcrop communities in the eastern United States.

Surveys of local assemblages of plants and their pollinators are among the most useful ways to evaluate specialization in pollination and to discuss the patterns of plant-pollinator interactions among ecosystems. The high-altitude grasslands from southeastern Brazil constitute diminutive island-like formations surrounded by montane rainforests. We registered the floral traits of 124 species from the Serra da Bocaina grasslands (about 60% of the animal-pollinated species of this flora), and determined the pollinators of 106 of them. Asteraceae (40 species) and Melastomataceae (10 species) were prominent, while most families were represented by few species. The predominant floral traits were: dish or short-tubular shape; nectar as a reward; and greenish or violaceous colors. Pollinators were divided into eight functional groups (small bees, syrphids, other dipterans, etc.) and small bees, wasps, and large bees were the most important pollinators. Butterflies, beetles, and hummingbirds were poorly represented, and no bats, hawkmoths, or odor-collecting bees were detected. Plants were grouped in nine pollination systems, among which nectar-flowers pollinated by bees (28%), by wasps or wasps and flies (21%), or by several insect groups (19%) were the most representative. With regard to the degree of specialization, plant species were classified according to their number of pollinator groups. About 33% of the species were monophilous and 30% were oligophilous (i.e., pollinated by one or two functional groups, respectively). The remaining species were either polyphilous (17%) or holophilous (19%), a highly generalist system in which at least three groups act as indistinct pollinators. The general trends of the floral traits and plant-pollinator interactions at the Bocaina grasslands resemble those of biogeographic-connected ecosystems, such as the Venezuelan arbustal, and the Brazilian campo rupestre and cerrado. However, in the Bocaina grasslands, the mean number of pollinator types per plant was 2.09, one of the highest values obtained for worldwide floras. The origin of the high-altitude grasslands is linked to episodes of expansion and retraction due to glacial events. Such a situation may have favored species able to quickly occupy new habitats, including those that do not depend on a few highly specialized pollinators. The prevalence of Asteraceae may also be linked to more generalized pollination systems. Alternatively, some floral traits, such as spontaneous self-pollination and long-lived flowers, may be advantageous for species with more specialized systems in these grasslands with harsh climatic conditions and low rates of pollinator visitation.

The North American–Greenlandic genus Boechera Á. Löve & D. Löve (Brassicaceae) is distinguished from other phylogenetic lineages recognized within the artificial taxon Arabis L. s.l., in which it has formerly been included, by its base chromosome number x = 7. Based on outgroup comparisons, we consider this chromosome number to be derived from an ancestral genome comprising eight chromosomes. Chromosome counts are now available for about half of the species names listed in the most recent taxonomic treatments of the genus. An analysis of the karyological differentiation with respect to chromosome numbers was performed, and these patterns were correlated with data on pollen viability and population genetic measures in order to deduce modes of reproduction. This approach allowed us to distinguish three main groups: sexual, amphi-apomictic, and apomictic species, respectively. We focused further on the cytology of gametes, especially on that of pollen, and we discuss its role in the formation of new genotypes and cytotypes. Evidence for the following evolutionary phenomena is currently available: (1) allopolyploidization, (2) homoploid hybrid formation, and (3) establishment of viable offspring by means of fusion of highly aneuploid gametes, which resulted from irregular meiotic divisions. In contrast, there is no strict evidence demonstrating the occurrence of autopolyploidization. Boechera experts have just started to integrate evolutionary concepts derived from molecular analyses into taxonomic research, and profound changes, with respect to species definition and circumscription, are to be expected in the near future. The identified modes of reproduction and evolutionary phenomena will contribute to the development of a theoretical and practical basis on which future taxonomic classifications and species concepts can be based.