Free amino acids as taxonomic characters in the tribe Arundinelleae (Gramineae)

This report records the results of a pilot study on the usefulness of free amino acids in the taxonomy of the tribe Arundinelleae (Gramineae). The work, carried out on a Beckman Model 120C Amino Acid Analyzer and using 70% ethanolic extracts, indicated patterns of variation unrelated to those found in traditional classifications. The amino acid variation encountered should be considered taxonomic noise; this example supports the view that free amino acids may not be of general value in higher plant systematics.     

The systematic value of flower structure in Crotalaria and related genera of the tribe Crotalarieae (Fabaceae)

Flowers in the tribe Crotalarieae of the family Fabaceae are generally adapted to bee pollination mechanisms. Molecular systematics have recently provided a major step towards a profound insight into generic relationships, thereby creating the opportunity to re-evaluate the taxonomic and functional significance of flower structure in the tribe, with emphasis on the large genus Crotalaria. A representative sample of flowers from 211 species was dissected to record morphological character states. These data were supplemented from the literature to allow for generalizations for the tribe as a whole. Six structural–functional flower types were identified: (1) pump; (2) gullet; (3) hugging; (4) saddle; (5) tunnel and (6) brush (saddle and tunnel types described here for the first time). Crotalaria uniquely has the brush type, characterized by a rostrate keel, highly dimorphic anthers, stylar trichomes and elaborate callosities on the standard petal. Remarkably, Crotalaria and Bolusia are the only genera of the tribe Crotalarieae with callosities present in all of the species. In other genera, callosities are generally absent or infrequent. Trends towards specialization of pollination syndromes are apparent as assemblages of apomorphic states that co-occur in what we refer to here as “specialized flowers”; individual characters are labile or non-homologous (e.g. callosities) and diagnostically less valuable. Unique combinations of flower characters are often useful to support current generic concepts in Crotalarieae.     

The systematic significance of morphological and anatomical variation in fruits of Crotalaria and related genera of tribe Crotalarieae (Fabaceae)

The phylogenetic and taxonomic significance of morphological and anatomical trends in fruits of tribe Crotalarieae has been evaluated, with emphasis on the genus Crotalaria and its seemingly distinctive, inflated and balloon‐shaped pods. In addition to the normal explosive dehiscence as a means of dispersal, several genera (including Crotalaria) show independent evolution of modifications apparently adapted for dispersal by wind, water and gravity. Transverse sections were made of mature pods of 142 species from the 12 currently recognized genera of Crotalarieae. The taxa differ in the orientation of the fibres (related to dehiscence or non‐dehiscence), the overall thickness of the fruit wall, the relative proportions of the pericarp layers, the degree of lignification and the presence or absence of trichomes. Three basic pericarp types can be distinguished: type I, with one, two or three zones of various numbers of cell layers of fibres (almost all genera); type II, with a single cell layer of fibres (only in Rothia, Robynsiophyton, Lebeckia and Lotononis sections Listia and Leobordea); and type III, with one zone of several cell layers of gelatinous fibres and multicellular trichomes associated with the endocarp (only in some species of Calobota and Wiborgiella). Considerable variation was encountered in the tribe, but Crotalaria appears to be rather uniform, with type I predominating. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 165 , 84–106.     

A taxonomic revision of the genus Pachyrhizus (Fabaceae -Phaseoleae)

The genus Pachyrhizus is revised in order to establish the distribution of the species and their variation. Three species in cultivation ( P. erosus, P. tuberosus and P. ahipa ) and two species only occurring in the wild ( P. ferrugineus and P. panamensis ) are recognized. P. strigosus is considered conspecific with P. erosus . All the infraspecific taxa proposed by Clausen are considered untenable. The new combination P. ferrugineus is made for what was previously know as P. vernalis .     

近年来中国国产豆科的属级分类学变动

豆科是被子植物中仅次于菊科和兰科的第三大科, 包含约791属, 19,325-19,560种, 其中许多分类群具有重要的经济价值。自《中国植物志》出版以来, 随着分子系统学的不断发展, 不少豆科属的范畴发生了变动。本文结合国内外的多项研究成果, 以1998年完整出版的《中国植物志》豆科相关卷册中的属为基准, 对近年来国产豆科植物的属的分类学变动进行了整理和总结, 包括32个分类学处理以及4个新记录属, 以期为未来国产豆科植物的分类学研究工作提供参考。     

Sesquiterpene lactones as taxonomic characters in the asteraceae

The Asteraceae is characterized by structurally diverse sesquiterpene lactones and furanosesquiterpenes. In this review the tribal, subtribal and generic distribution of sesquiterpene lactones is examined and the compounds’ utility as taxonomic characters discussed. Sesquiterpene lactones fulfill the major requirements for good analytic and synthetic characters. Studies of infraspecific sesquiterpene lactone variation indicate that different elements within complex taxa are often defined by distinct chemistries, termed chemotypes. Chemotypes have been identified within many of the thoroughly investigated taxa:Ambrosia camphorata, A. chamissonis, A. confertiflora, theA. cumanensis-A. psilostachya-A. artemisiifolia complex,A. dumosa, Artemisia tridentata, Gaillardia pulchella andMelampodium leucanthum. Such an analytic usage is mostly restricted to the infraspecific level. Synthetic usage at the interspecific level and above profits from the application of a biogenetically based methodology for sorting out the complex molecules’ carbon-skeletal and substitutional features into unit characters. Cladistics or Hennigian phylogenetic systematics provides a useful framework for such an analysis. Preliminary surveys indicate that sesquiterpene lactones are especially good characters for differentiating subtribes within several major tribes: the Vernonieae, Heliantheae and Mutisieae. As yet, too few data are available for other tribes to discern such patterns. Species surveys inVernonia, Ambrosia, Iva, Parthenium,Tetragonotheca andArtemisia demonstrate that sesquiterpene lactones are useful in discerning infrageneric groups. The biogenetic cladistic analysis of the interspecific sesquiterpene lactone variation inIva shows the efficacy of this analytical methodology. At present, such biogenetically based approaches are impeded by limited biosynthetic evidence and the erratic distribution of sesquiterpene lactones within the family. Instances of apparent displacement of sesquiterpene lactones by other terpenoids (i.e. sesquiterpene furans, alcohols and acids, diterpenes, diterpene acids, etc.) at various taxonomic levels suggest that ultimately sesquiterpene lactones must be interpreted as taxonomic characters in the context of the family’s total terpene chemistry. All taxa from which sesquiterpene lactones have been reported are listed together with the compound names, major structural features and the literature cited. A less-complete listing is provided for taxa producing furanosesquiterpenes. Structures for all reported compounds are included. Two appendices listing alphabetically taxa and compounds and relevant text page numbers permit cross-indexing of plants and compounds.     

Cytomorphological characters supporting the taxonomic validity ofCyanothece (Cyanoprokaryota)

The fine structure of the type species of the genusCyanothece Komárek 1976,C. aeruginosa, is described and compared with the main cytological characteristics of morphologically related members of the generaCyanobium, Cyanobacterium andSynechococcus. Several morphological features, such as cell walls with thick outer layers containing a special type of vesicles, position of thylakoids, keritomy (net-like appearance of protoplast caused by arrangement of thylakoids, net-like nucleoids and/or by tendency to form intrathylakoidal spaces) and a special structure of mucilaginous envelopes were found to be characteristic of this genus, supporting its separate position among coccal cyanoprokaryotes (cyanobacteria, cyanophytes). The taxonomic significance of ultrastructural features in all mentioned genera is discussed.     

Aspalathus crewiana sp. nov. (Crotalarieae,Fabaceae) from the Western Cape Province,South Africa

A new species, Aspalathus crewiana is described and illustrated. It is closely similar to A. lenticula in the strongly rostrate keel petals and thorny leaflets, but differs in the subulate, spine‐tipped bracts, bracteoles and calyx lobes, presence of a pseudo‐peduncle and larger flowers. The new species, like A. lenticula, is placed in the Terminales group of A. subgenus Aspalathus. It is known from only two localities in the Western Cape where it was collected in Swartland Granite Renosterveld.     

Terpenes as taxonomic characters in Salvia section Audibertia

A survey of terpene differences in the 19 species ofSalvia indigenous to California and Baja California suggests that identification of species is possible solely on the characteristic composition of terpenes. Further, differences between two introgressing species (5.apiana and 5.mellifera) are such that terpenes may be treated as characters from which hybrid indices and histograms may be formulated. Statistical comparison of these data with those from morphology shows a highly significant correlation.     

Variability in the taxonomic characters of Black Sea gyrodactylids (Monogenea)

Variability of the haptoral hard parts of four Black Sea Gyrodactylus species (G. alviga Dmitrieva & Gerasev, 2000; G. crenilabri Zaika, 1966; G. flesi Malmberg, 1957; G. sphinx Dmitrieva & Gerasev, 2000) was studied in relation to season, host and geographical variability. A discriminant analysis was carried out on the measurements of 14 characters of the haptor of all four species. The haptoral hard parts of the investigated gyrodactylids decrease in size with an increase in water temperature. It is known that life-span of gyrodactylids is negatively correlated with water temperature and they exhibit peak intensities at low temperature. At the same time, life-span is considered to be a general indicator of a favourable environment. Therefore, high water temperature is not apparently advantageous for gyrodactylids. In the case of low marine salinity, in adapted species the sizes of the haptoral hard parts are larger at lower levels of salinity and vice versa for typical marine species. Lastly, in specimens parasitising the primary host, these features are larger than in those parasitising a secondary host. It is possible to say that, in general, the more favourable the environment for gyrodactylids the larger their haptoral hard parts. Unfavourable environmental conditions reduce the time of embryogenesis, which has a dual effect on gyrodactylids: positive in relation to their reproduction (by increasing the reproduction rate) and negative in relation to their development (by decreasing the size of the haptoral hard parts).     

Pollen morphology and its taxonomic significance in the tribe Gochnatieae (Compositae, Gochnatioideae)

In the context of recent molecular phylogenies of the basal grades of Compositae, we investigated the utility of pollen morphology within the tribe Gochnatieae. The pollen of 64 species of Anastraphia, Cnicothamnus, Cyclolepis, Gochnatia, Pentaphorus, and Richterago was studied using light microscopy and scanning electron microscopy. In addition, three extra-Gochnatieae genera (Ianthopappus, Leucomeris, and Nouelia) were examined as they were traditionally morphologically related to members of the tribe Gochnatieae. Three of the species of Gochnatieae were examined using transmission electron microscopy. Two pollen types, and two new subtypes, have been recognized on the basis of the pollen shape, size, and exine sculpture. The pollen features of Gochnatia sect. Moquiniastrum and G. cordata are similar and distinctive within the genus and support the recently re-circumscribed section Hedraiophyllum. Within the species with echinate pollen surface, the distinctive spine length of Anastraphia supports its recent resurrection as a genus. The identity of Pentaphorus could not be supported by pollen features as was for other morphological characteristics. The pollen features shared across Cyclolepis, Ianthopappus, Leucomeris, Nouelia and Gochnatia sect. Moquiniastrum, as well as those shared by Richterago and Anastraphia could be a result of parallel evolution.     

Bobgunnia, a new African genus of tribe Swartzieae (Fabaceae, Faboideae)

A new genus, Bobgunnia, is established in tribe Swartzieae for the African species of Swartzia. Two new combinations are made: B. fistuloides and B. madagascariensis. The new genus has seeds, unlike the remainder of tribe Swartzieae but like the other tribes of Faboideae. The systematic position of Swartzieae is reevaluated.