Englera 18

Abstract

Zarre-Mobarakeh, S.: Systematic revision of Astragalus sect. Adiaspastus, sect. Macrophyllium and sect. Pterophorus (Fabaceae). – Englera 18: 1-219. 1999. – ISBN 3-921800-42-0.
 
Three sections of Astragalus, i.e. A. sect. Adiaspastus, sect. Macrophyllium and sect. Pterophorus are revised. The circumscription of the sections is modified to make them natural. However, they are not sharply delimited, because there are some intermediate species between these three sections and A. sect. Rhacophorus, the largest section of tragacanthic astragali with almost 100 species.


A. sect. Acidodes, whose systematic position was very controversial, is reduced to synonymy of sect. Adiaspastus, because of the close affinity of the two lectotypes. Since the monotypic A. sect. Brachycalyx has close allies within sect. Adiaspastus, and since there are no important features for separating it from the latter, it is also reduced to synonymy. On the basis of some important trends, an informal grouping is undertaken for A. sect. Adiaspastus. The A. sahendi group which was treated as belonging to A. sect. Acanthophace in the most recent literature, is transferred to A. sect. Adiaspastus as a consequence of important differences in hair micromorphology. The species of the A. cerasocrenus group, which occur in the Kopet Dagh mountain range and in Afghanistan, are transferred to A. sect. Rhacophorus because of certain apomorphies in calyx structure, standard shape, etc.


The presence of two persisting bracteoles resembling the calyx teeth, is the only feature separating A. sect. Pterophorus from sect. Rhacophorus. The species of this section do not occur east of Central Anatolia. The exact systematic position of A. sect. Pterophorus and its possible identity with sect. Rhacophorus is still to be examined. A. (sect. Pterophorus) condensatus is one of the most variable species within thorny Astragalus.

A. sect. Macrophyllium seems to be a natural group characterized by a sturdy habit and usually glabrous leaves. A. glabrifolius is the only species within this section which possesses a firm calyx, a character connecting this species to A. sect. Adiaspastus. It is found in Afghanistan and shows the only disjunction in the distribution of A. sect. Macrophyllium. A. oleaefolius is the most widespread species within the section and shows a considerable variation.

A cladistic analysis including almost all sections of thorny Astragalus is performed, using mainly morphological characters. These are the most important results: 1. Tragacanthic astragali are monophyletic, but separating them from Astragalus makes the latter paraphyletic. 2. Except for A. sect. Adiaspastus, all sections of tragacanthic Astragalus show an unresolved branching pattern, a result of high homoplasy exhibited by morphological characters. 3. Maintaining the monotypic A. sect. Diacme and sect. Polystegis is supported. The systematically isolated A. psilodontius should be assigned to a section of its own. 4. A. sect. Megalocystis, in the present form, is polyphyletic. Transferring some species from this section to sect. Microphysa and keeping the monotypic A. sect. Eriostoma make it monophyletic. 5. A. sect. Tricholobus is to be included in A. sect. Campylanthus, otherwise the latter is paraphyletic. 6. A. sect. Poterion is not closely related to other sections of Bunge’s subgenus Calycophysa.

Based on a cladistic analysis the patterns of homoplasy are discussed. Many characters, e.g. flower size, considered earlier to be very important in distinguishing natural groups, show a very homoplastic nature, which disapproves the classifications based on them.

Distribution maps, keys to the species, descriptions and synonymies are provided. Most of the names are typified. A diagnostic key to all sections of thorny Astragalus is also given.

: Additional selected specimens seen


The list of additional selected specimens seen is available in the following file formats:
ANSI-txt (97K) / RTF (180K) / MS-WORD 2 (155K)
 

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