Taxonomic significance of the abaxial lemma surface in southern African members of Helictotrichon (Poaceae)

dc.contributor.authorMashau, A.C.
dc.contributor.authorVan Wyk, Abraham Erasmus (Braam)
dc.contributor.authorFish, Lyn
dc.date.accessioned2016-04-15T07:52:07Z
dc.date.available2016-04-15T07:52:07Z
dc.date.issued2015-03-25
dc.description.abstractBACKGROUND : Helictotrichon (excluding Amphibromus, Avenula, Helictochloa and Tricholemma), a genus of temperate C3 grasses, is represented by 14 species in southern Africa. Members of the genus are difficult to identify at species level on the basis of macromorphology alone. OBJECTIVES : The primary objective of this study was to investigate the usefulness of the micromorphology of the lemma surface for differentiating amongst the southern African members of Helictotrichon. METHOD : Lemma surfaces were studied with scanning electron microscopy (SEM). Lemmas were obtained from herbarium specimens housed in the National Herbarium, Pretoria (PRE). These were mounted on aluminium stubs using double-sided adhesive tape, sputter-coated with gold, and photographs were taken using a J840 scanning electron microscope. RESULTS : Based on whether the lemma surface is smooth, papillate, scaberulous, scabrid or a combination of these, five groups of species are distinguished. All species, except Helictotrichon barbatum which has a smooth lemma surface, have small prickles (scaberulous). Helictotrichon leoninum, Helictotrichon quinquesetum and Helictotrichon rogerellisii have only small prickles, whilst Helictotrichon dodii, Helictotrichon hirtulum, Helictotrichon namaquense and Helictotrichon roggeveldense have, in addition, medium to large prickles (scabrid). Helictotrichon capense, Helictotrichon longifolium, Helictotrichon longum and Helictotrichon turgidulum have a combination of small prickles and papillae whilst Helictotrichon galpinii and Helictotrichon natalense have a combination of all three. A key to the groups and photos of the different types of surfaces are provided. CONCLUSION : The micromorphology of the lemma surface was shown to be of considerable taxonomic significance and to be extremely useful for differentiating amongst species.en_ZA
dc.description.departmentPlant Scienceen_ZA
dc.description.librarianam2016en_ZA
dc.description.sponsorshipSouth African National Biodiversity Instituteen_ZA
dc.description.urihttp://www.abcjournal.orgen_ZA
dc.identifier.citationMashau, A.C., Fish, L. & Van Wyk, A.E., 2015, ‘Taxonomic significance of the abaxial lemma surface in southern African members of Helictotrichon (Poaceae)’, Bothalia 45(1), Art. #1393, 8 pages. http://dx.DOI. org/10.4102/abc.v45i1.1393.en_ZA
dc.identifier.issn0006-8241 (print)
dc.identifier.issn2311-9284 (online)
dc.identifier.other10.4102/abc.v45i1.1393
dc.identifier.urihttp://hdl.handle.net/2263/52032
dc.language.isoenen_ZA
dc.publisherAOSIS OpenJournalsen_ZA
dc.rights© 2015. The Authors. Licensee: AOSIS OpenJournals. This work is licensed under the Creative Commons Attribution License.en_ZA
dc.subjectHelictotrichonen_ZA
dc.subjectGenusen_ZA
dc.subjectMicromorphologyen_ZA
dc.subjectLemmasen_ZA
dc.titleTaxonomic significance of the abaxial lemma surface in southern African members of Helictotrichon (Poaceae)en_ZA
dc.typeArticleen_ZA

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