A taxonomic revision of the genus Gouania Jacq. (Rhamnaceae) is presented for Madagascar and the other western Indian Ocean islands. Seventeen species are recognized, of which nine are described and published as new (all endemic to Madagascar): G. ambrensis Buerki, Phillipson & Callm., G. callmanderi Buerki, G. cupreifolia Buerki, Phillipson & Callm., G. cupuliflora Buerki, Phillipson & Callm., G. gautieri Buerki, Phillipson & Callm., G. perrieri Buerki, Phillipson & Callm., G. phillipsonii Buerki, G. taolagnarensis Buerki, Phillipson & Callm., and G. zebrifolia Buerki, Phillipson & Callm. Sixteen species occur in Madagascar, of which 13 are endemic and three are common to Madagascar and one or more of the smaller Indian Ocean islands. The latter include G. laxiflora Tul., a species which is also present on mainland Africa. One species, G. mauritiana Lam., is endemic to Réunion Island. We recognize two subspecies within G. scandens (Gaertn.) R. B. Drumm.: G. scandens subsp. scandens and G. scandens subsp. glandulosa (Boivin ex Tul.) Buerki, Phillipson & Callm., the latter transferred from G. glandulosa Boivin ex Tul. Past confusion about the identity of this species is discussed. Five names are lectotypified: G. aphrodes Tul., G. glandulosa [= G. scandens subsp. glandulosa], G. laxiflora, G. lineata Tul., and G. tiliifolia Lam. Both lectotype and epitype are designated for G. mauritiana. Conservation assessments are provided for all species within their primary areas of occurrence.
Heliophila (ca. 73 spp.), the ditypic Cycloptychis and Thlaspeocarpa, and the monotypic Schlechteria, Silicularia, Brachycarpaea, and Chamira are endemic to the Cape region of South Africa, where they are the dominant genera of Brassicaceae. They may be regarded as the most diversified Brassicaceae lineage in every aspect of habit, leaf, flower, and fruit morphology. The characters used in the separation of these genera and their species, especially fruit type (silique vs. silicle), dehiscence (dehiscent vs. indehiscent), compression (latiseptate vs. angustiseptate), and cotyledonary type (spirolobal, diplecolobal, twice conduplicate), have been used extensively in the delimitation of tribes. The relationship and taxonomic limits among these genera are unclear and controversial. The present ITS study demonstrates the monophyly of tribe Heliophileae, with Chamira as sister clade. The other five smaller genera above are nested within two of the three main lineages of Heliophila, to which they should be reduced to synonymy. The current study reveals parallel evolution of fruit characters often used heavily in the traditional classification schemes of the family. However, the arrangement of species into three main clades largely corresponds with the distribution of morphological characters (e.g., habit, leaf shape, seed structure, inflorescence type, and presence/absence of basal appendages on the pedicels, petals, and staminal filaments) not adequately accounted for in previous studies. Estimation of divergence times of the main lineages of Heliophila is in agreement with recent estimations in other plant groups, all of which date the diversification against a background of aridification in the Pliocene and Pleistocene. Species of one main clade are perennial, microphyllous shrubs/subshrubs typically restricted to poor sandstone soils in the southwestern and western parts of the Cape Floristic Region of South Africa. Species of the other two clades are predominantly annuals that grow in more arid regions of Namibia and Namaqualand, as well as in the above sandstone areas of the Cape Region. The adaptive significance of various floral structures is discussed in terms of their possible role in the rapid diversification within Heliophila.
International goals have been set to protect global plant diversity and limit ecosystem damage due to climate change, but large-scale effects of changing climate on species distributions have yet to be fully considered in conservation efforts. For sub-Saharan Africa we study the shifts in climatically suitable areas for 5197 African plant species under future climate models for the years 2025, 2055, and 2085 generated by the Hadley Center’s third generation coupled ocean-atmosphere General Circulation Model. We use three species distribution models, a “Box model,” a simple genetic algorithm, and a Bayes-based genetic algorithm. The results show major shifts in areas suitable for most species with large geographical changes in species composition. The areas of suitable climate for 81%–97% of the 5197 African plant species are projected to decrease in size and/or shift in location, many to higher altitudes, and 25%–42% are projected to lose all of their area by 2085. In particular, the models indicate dramatic change in the Guineo-Congolian forests, mirroring proposed ecological dynamics in the past. Although these models are preliminary and may overestimate potential extinctions, they suggest that efforts to protect African plant diversity should take future climate-forced distribution changes into account.
This monograph recognizes 29 species, 2 subspecies, and 14 formae in the Americas. Conventional means have been employed in determining species limits. The genus is divided into five sections, of which two are described variety is accorded specific rank. Eleven taxa have been altered in rank, 17 proposed names are reduced to synonymy under other taxa of ageratum, and eleven names are removed from the genus. Chromosome numbers are reported for the first time for four species, three chromosome numbers are confirmed, and corrected determinations are made for vouchers of nine previously published chromosome numbers. Taxonomic literature, history of cultivation, economic uses, common names, geography, and generic relationships are discussed. New keys, ecological data, and flowering and fruiting dates are included for the species and the intraspecific taxa. There are 16 distribution maps and illustrations of the new species.
Three species of Solarium are included in a new section, Solarium sect. Allophyllum. Two of the species, S. allophyllum and S. mapiriense, have been previously known; the third, S. morellifolium Bohs, is described as new. The combination of characters exhibited by members of this section, such as unbranched hairs, 2-3-leaved sympodial units, simple leaves with decurrent bases, and tapered anthers, is unique to this group and does not agree well with any existing subgenus of Solarium. Journal Article
Solanum allophyllum has previously been placed in Cyphomandra and in Solarium. This species has a number of morphological features not found in Cyphomandra, but has been included in the genus because it has a similar growth habit, three-leaved sympodial units with inflorescences in branch forks, and tapered anthers with an abaxial thickening. When each of these characters is closely examined, however, important differences are found between the taxa, indicating that the features they share may not be structurally homologous. Journal Article
The generic limits of Hymenocallis have been variously proposed by different taxonomic workers, often without discussion or data. The genera Leptochiton, Ismene, Elisena, and Pseudostenomesson have been included with Hymenocallis, lumped together as the genus Ismene, or maintained as distinct genera. Recent cladistic analysis of plastid and nrDNA for Amaryllidaceae support a distinct tribe Hymenocallideae. Cladistic analyses of morphology, and plastid (trnL-F region) and nuclear ribosomal DNA (ITS) are presented alone and in combination for the tribe. Leptochiton is sister to the rest of the genera in the tribe in all analyses. While Hymenocallis is always resolved as monophyletic, Ismene is variably paraphyletic or monophyletic. The combined sequence data produce the most resolved and best-supported phylogeny, wherein Hymenocallis and Ismene are monophyletic sister genera. These data support an origin for the tribe in the Andes, with vicariant distribution of the largely Mesoamerican Hymenocallis. Formal recognition of Ismene subg. Elisena and Pseudostenomesson is established.
A taxonomic treatment of Trisetum Pers. for South America, is given. Eighteen species and six varieties of Trisetum are recognized in South America. Chile (14 species, 3 varieties) and Argentina (12 species, 5 varieties) have the greatest number of taxa in the genus. Two varieties, T. barbinode var. sclerophyllum and T. longiglume var. glabratum, are endemic to Argentina, whereas T. mattheii and T. nancaguense are known only from Chile. Trisetum andinum is endemic to Ecuador, T. macbridei is endemic to Peru, and T. foliosum is endemic to Venezuela. A total of four species are found in Ecuador and Peru, and there are two species in Venezuela and Colombia. The following new species are described and illustrated: Trisetum mattheii Finot and T. nancaguense Finot, from Chile, and T. pyramidatum Louis-Marie ex Finot, from Chile and Argentina. The following two new combinations are made: T. barbinode var. sclerophyllum (Hack, ex Stuck.) Finot and T. spicatum var. cumingii (Nees ex Steud.) Finot. A key for distinguishing the species and varieties of Trisetum in South America is given. The names Koeleria cumingii Nees ex Steud., Trisetum sect. Anaulacoa Louis-Marie, Trisetum sect. Aulacoa Louis-Marie, Trisetum subg. Heterolytrum Louis-Marie, Trisetum subg. Isolytrum Louis-Marie, Trisetum subsect. Koeleriformia Louis-Marie, Trisetum subsect. Sphenopholidea Louis-Marie, Trisetum malacophyllum Steud., Trisetum variabile E. Desv., and Trisetum variabile var. virescens E. Desv. are lectotypified.
A taxonomic treatment of Trisetum, Peyritschia, and Sphenopholis for Mexico and Central America is given. In Mexico and Central America four species of Peyritschia, two species of Sphenopholis, and 17 species of Trisetum s. str. are recognized. Peyritschia deyeuxioides and P. pringlei range from Mexico to Ecuador, P. koelerioides is found in southern Mexico to Guatemala, and P. humilis is endemic to Mexico. Sphenopholis obtusata ranges from Canada to the U.S.A. and Mexico, whereas S. interrupta is found in the southwestern U.S.A. and Baja California, Mexico. Mexico has the largest number of Trisetum species at 15, and nine of these are endemic. Five species of Trisetum are found in Guatemala, three in Costa Rica and Panama, and a single species is found in Honduras and the Dominican Republic. A new subgenus Deschampsioidea (Louis-Marie) Finot in Trisetum is proposed. Four new species of Trisetum from Mexico are described and illustrated: T. durangense Finot & P. M. Peterson, T. martha-gonzaleziae P. M. Peterson & Finot, and T. spellenbergii Soreng, Finot & P. M. Peterson (all in subg. Deschampsioidea); and T. ligulatum Finot & Zuloaga (in subg. Trisetum, sect. Trisetaera). Keys for the genera, subgenera, sections, and species of Trisetum, Peyritschia, and Sphenopholis that occur in Mexico and Central America are given. The names Trisetum gracile E. Fourn. and Trisetum subsect. Deschampsioidea Louis-Marie are lectotypified.
Studies of angiosperm leaf cuticles from the Lower Cretaceous Potomac Group reinforce previous evidence for a Cretaceous adaptive radiation of the flowering plants and suggest unsuspected trends in the evolution of stomata and trichomes. Early Potomac Group angiosperm leaf cuticles (Zone I of Brenner or Aptian?) show little interspecific structural diversity, particularly in stomatal organization. All species conform to the same highly plastic pattern of variation in subsidiary cell arrangement, in which the stomata on a single leaf conform to several types, including paracytic, hemiparacytic, anomocytic, laterocytic, and weakly cyclocytic. Several species resemble extant Chloranthaceae and Illiciales, but none represents a modem family. Later leaves (Subzone 11-B of Brenner, or Albian) exhibit greater interspecific structural diversity, particularly in stomatal organization. Three new patterns of variation in subsidiary cell arrangement are present in addition to the older one and each has a subset of the variation present in the older pattern. Cuticular anatomy is consistent with proposed leaf affinities to Platanaceae and Rosidae. The stratigraphic trend in cuticle types supports the concept that the subclass Magnoliidae includes the most primitive living angiosperms. However, it also suggests that the uniformly paracytic stomatal pattern characteristic of Magnoliales, generally considered primitive for the flowering plants, may actually be derived from the variable condition found in Zone I leaves.
Because of its complex taxonomic history, the identity, circumscription, and systematic position of Patima (Rubiaceae) have been nebulous. After a careful morphological analysis, Patima is here recognized as a monospecific genus endemic to the eastern portion of the Guayana Shield. Two names in Rubiaceae are here treated as new synonyms with Patima guianensis Aubl., Patima formicaria I. M. Johnst. and Hoffmannia megistophylla Standl. Two names described under Patima, P. laxiflora Benth. (here lectotypified) and P. forsythii DC., are shown to belong to other Rubiaceae genera. Aegiphila gleasonii Moldenke (described as a taxon in the Verbenaceae) is another new synonym of Patima guianensis. Patima is here included in the tribe Hamelieae (subfamily Cinchonoideae) because of its morphological features and its overall similarity to Hoffmannia. The presence of raphides in Patima (declared to be absent by previous authors) is here confirmed and discussed. A full account of the taxonomic history and systematic position of Patima, complete typification, complete generic and specific descriptions, a distribution map, a line drawing, photographs of raphides, and observations on ant/plant interaction are provided.
Leaf architecture and epidermal morphology of 259 species representing 51 genera in the Phyllanthoideae (Euphorbiaceae) vary in a taxonomically significant way. Most tribes are relatively homogeneous and well defined, with most exceptions being tribes containing herbaceous or highly xerophytic genera. Tribes that are generally considered to be closely related have similar leaves. Increase in venational organization correlates with specialization in floral morphology. Foliar morphology also indicates genera whose relationships warrant reconsideration, particularly Celianella, Croizatia, Didymocistus, Jablonskia, Neowawraea, and Uapaca. Theoid teeth and incipient or vestigial actinodromy support placement of Euphorbiaceae near the Violales in the Dilleniidae, rather than in the Rosidae.
Typescript. Includes abstract. "The research was conducted at the Missouri Botanical Garden" Thesis (M.S.)--University of Missouri--St. Louis, 1989. Includes bibliographical references (leaves 166-180). Photocopy.
The genus Strephonema (Combretacea) comprises three species restricted to the wet tropical forests of West Africa (S. pseudocola) and Central Africa (S. mannii and S. sericeum). A possible fourth species from Central Africa cannot as yet be distinguished for want of flowers. The presence of a simple receptacle that cannot be divided into a distinct upper and lower part, and of a large fruit with the remnants of the flower located near the base rather than at the top, makes it possible to distinguish this genus from all other Combretaceae. Strephonema species are small to dominant fores-trees; S. mannii is only known from regular inundated forests. A key to the species is presented, along with brief descriptions and complete synonym. Several lectotypes are designated.
Volcan Mombacho is a moderate sized (1,345 m elev.), quiescent volcano with one of two cloud forests in southwestern Nicaragua. Of 457 species listed, 80 are pteridophytes and 87 are orchids. The species richness of these groups may be accounted for by their high fecundity and dispersibility. This study has revealed only one endemic species. Since Mombacho is the apparent northern range limit of several orchid species, it is suggested that the flora of the cloud forest has most of its affinities with Costa Rica. The lack of several wide ranging species on Mombacho which are known only as far south as northern Nicaragua further supports this contention. As with most of tropical America, the cloud forests of Mombacho are threatened by exploitation of their natural resources.
A systematic study based primarily on morphology, suggests that patterns of variation in Sarcolaena Thouars, a member of the Malagasy endemic family Sarcolaenaceae; are best resolved by recognizing eight species. Keys for identification of the genera of Sarcolaenaceae and species of Sarcolaena are provided, as well as a discussion of the overall morphology of Sarcolaena and complete descriptions of its species. Two species, S. grandiflora and S. multiflora, are lectotypified in the present study.
We present the results of two exploratory parsimony analyses of DNA sequences from 475 and 499 species of seed plants, respectively, representing all major taxonomic groups. The data are exclusively from the chloroplast gene rbcL, which codes for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO or RuBPCase). We used two different state-transformation assumptions resulting in two sets of cladograms: (i) equal-weighting for the 499-taxon analysis; and (ii) a procedure that differentially weights transversions over transitions within characters and codon positions among characters for the 475-taxon analysis. The degree of congruence between these results and other molecular, as well as morphological, cladistic studies indicates that rbcL sequence variation contains historical evidence appropriate for phylogenetic analysis at this taxonomic level of sampling. Because the topologies presented are necessarily approximate and cannot be evaluated adequately for internal support, these results should be assessed from the perspective of their predictive value and used to direct future studies, both molecular and morphological. In both analyses, the three genera of Gnetales are placed together as the sister group of the flowering plants, and the anomalous aquatic Ceratophyllum (Ceratophyllaceae) is sister to all other flowering plants. Several major lineages identified correspond well with at least some recent taxonomic schemes for angiosperms, particularly those of Dahlgren and Thorne. The basalmost clades within the angiosperms are orders of the apparently polyphyletic subclass Magnoliidae sensu Cronquist. The most conspicuous feature of the topology is that the major division is not monocot versus dicot, but rather one correlated with general pollen type: uniaperturate versus triaperturate. The Dilleniidae and Hamamelidae are the only subclasses that are grossly polyphyletic; an examination of the latter is presented as an example of the use of these broad analyses to focus more restricted studies. A broadly circumscribed Rosidae is paraphyletic to Asteridae and Dilleniidae. Subclass Caryophyllidae is monophyletic and derived from within Rosidae in the 475-taxon analysis but is sister to a group composed of broadly delineated Asteridae and Rosidae in the 499-taxon study.
Emerging Threats to Tropical Forests reveals the remarkably diverse panoply of perils to tropical forests and their biota, with particular emphasis on recent dangers. William F. Laurance and Carlos A. Peres identify four categories of emerging threats: those that have only recently appeared, such as the virulent chytrid fungus that is decimating rainforest amphibians throughout the tropical world; those that are growing rapidly in importance, like destructive surface fires; those that are poorly understood, namely global warming and other climatic and atmospheric changes; and environmental synergisms, whereby two or more simultaneous threatsâsuch as habitat fragmentation and wildfires, or logging and huntingâcan dramatically increase local extinction of tropical species. In addition to documenting the vulnerability of tropical rainforests, the volume focuses on strategies for mitigating and combating emerging threats. A timely and compelling book intended for researchers, students, and conservation practitioners, Emerging Threats to Tropical Forests will interest anyone concerned about the fate of the worldâs most threatened tropical ecosystems.
The genera Wunschmannia and Anomoctenium are united with Distictis. Necessary new combinations are D. staminea (Lam.) A. Gentry, D. stipularis (Mart. ex DC.) A. Gentry, and D. scabriuscula (Mart. ex DC.) A. Gentry. A new species, D. steyermarkii A. Gentry, related to the former members of Anomoctenium, is also described. A synopsis of the species of Distictis is included.