ABSTRACT
Character variation in Chaetobromus, a genus of palatable grasses endemic to the arid
western areas of southern Africa, was used to derive a classification reflecting taxonomic
and ecological pattern. The present study differs from earlier biosystematic investigations
by its much more intensive approach to sampling, with 75 anatomical, morphological and
cytological characters and 169 individual samples being used. The use of larger population
samples permitted quantification o~ variation within populations, in addition to that among
populations and groups.
Phenetic methods revealed the existence of three groups, approximating three formerly
described taxa and reflecting divergent ecological strategies in Chaetobromus. A lack of
diagnostic field characters argues against their recognition at species level, and
Chaetobromus Nees is here described as monotypic, the type species, C. involucratus
(Schrad.) Nees, comprising three subspecies C. involucratus subsp. involucratus, C.
involucratus subsp. villosus Verboom and C. involucratus subsp. dregeanus (Nees)
Verboom.
There is overlap among subspecies in most characters although many showed significant
mean differences. Within subspecies, character variation appears to be homogeneously
distributed with respect to population boundaries suggesting that these are likely to have
little impact on sampling. A investigation testing the effect of sample strategy on variation
capture and taxonomic group detection suggests that a sample of 10-15 specimens is
likely to account for most variation present.
Phylogenetically, Chaetobromus is included in the tribe Danthonieae, and, on morphological
evidence, is probably basal to a clade containing Pentaschistis, Pentameris and
Pseudopentameris. The genus appears to occupy a niche unique among the African
danthonioids, favouring lime-rich, basic soils and a strongly-seasonal winter-rainfall regime
with arid summers. Ecological differences among the subspecies are reflected in
differences in growth form and vegetative and reproductive phenologies. The niche
requirements of Chaetobromus may be adequately specific to explain the patchy
distribution of the genus.
Verboom, G (2021). An Investigation Of Character Variation In Chaetobromus Nees (Danthonieae: Poaceae) In Relation To Taxonomic And Ecological Pattern.. Afribary. Retrieved from https://tracking.afribary.com/works/an-investigation-of-character-variation-in-chaetobromus-nees-danthonieae-poaceae-in-relation-to-taxonomic-and-ecological-pattern-1
Verboom, George "An Investigation Of Character Variation In Chaetobromus Nees (Danthonieae: Poaceae) In Relation To Taxonomic And Ecological Pattern." Afribary. Afribary, 15 May. 2021, https://tracking.afribary.com/works/an-investigation-of-character-variation-in-chaetobromus-nees-danthonieae-poaceae-in-relation-to-taxonomic-and-ecological-pattern-1. Accessed 09 Nov. 2024.
Verboom, George . "An Investigation Of Character Variation In Chaetobromus Nees (Danthonieae: Poaceae) In Relation To Taxonomic And Ecological Pattern.". Afribary, Afribary, 15 May. 2021. Web. 09 Nov. 2024. < https://tracking.afribary.com/works/an-investigation-of-character-variation-in-chaetobromus-nees-danthonieae-poaceae-in-relation-to-taxonomic-and-ecological-pattern-1 >.
Verboom, George . "An Investigation Of Character Variation In Chaetobromus Nees (Danthonieae: Poaceae) In Relation To Taxonomic And Ecological Pattern." Afribary (2021). Accessed November 09, 2024. https://tracking.afribary.com/works/an-investigation-of-character-variation-in-chaetobromus-nees-danthonieae-poaceae-in-relation-to-taxonomic-and-ecological-pattern-1