Original Research

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

Aluoneswi C. Mashau, Lyn Fish, Abraham E. van Wyk
Bothalia | Vol 45, No 1 | a1393 | DOI: https://doi.org/10.4102/abc.v45i1.1393 | © 2015 Aluoneswi C. Mashau, Lyn Fish, Abraham E. van Wyk | This work is licensed under CC Attribution 4.0
Submitted: 11 November 2014 | Published: 25 March 2015

About the author(s)

Aluoneswi C. Mashau, Biosystematics & Research Collections Division, South African National Biodiversity Institute, South Africa; Department of Plant Science, University of Pretoria, South Africa
Lyn Fish, Biosystematics & Research Collections Division, South African National Biodiversity Institute, South Africa
Abraham E. van Wyk, Department of Plant Science, University of Pretoria, South Africa; H.G.W.J. Schweickerdt Herbarium, University of Pretoria, South Africa, South Africa


See Updates


Share this article

Bookmark and Share

Abstract

Background: 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.


Keywords

No related keywords in the metadata.

Metrics

Total abstract views: 2210
Total article views: 4797


Crossref Citations

No related citations found.