Gisekia diffusa
- Holotype: Type: Kenya, Dandu, Gillett 13041 (holotype K; isotype EA)
- 1. Gilbert, M. G. 1993: A review of Gisekia (Gisekiaceae). – Kew Bulletin 48(2): 343-356. http://doi.org/10.2307/4117942
- =Gisekia pharnaceoides var. pseudopaniculata in Kew Bull. 14(2): 235. 6 Oct 1960 syn. sec. Gilbert 19932
- Holotype: Kenya: Dandu, Gillett 13041 (holotype K; isotype EA)
- 2. Gilbert, M. G. 1993: A review of Gisekia (Gisekiaceae). – Kew Bulletin 48(2): 343-356. http://doi.org/10.2307/4117942
Notes
The distinction between this species and G. pharnaceoides was obscured by the inclusion within 'var. pseudopaniculata' of some laxer forms of G. pharnaceoides. The variety was originally rather vaguely separated primarily on the overall laxness of the inflorescence plus overlapping quantitative characters. When the material of var. pseudopaniculata was sorted more rigorously so as to exclude all collections with flowers in umbels, it was found that there were other correlated differences in the length and thickness of the pedicels and their behaviour in fruit: those of G. pharnaceoides are shorter, stouter and distinctly curved whilst G. diffusa as now defined always had long, straight, filiform pedicels. There was also a distinct (but difficult to describe) difference in habit: G. pharnaceoides, at least in tropical Africa, is basically procumbent with occasional vigorous stems ascending and producing branches with reduced leaves that only superficially look like a terminal inflores- cence whereas G. diffusa is erect to ascending and produces what seem to be true terminal cymes. The distinction is emphasised by field observations at Melka Guba in southern Ethiopia where the two species coexisted with no suggestion of any intermediates. The same is true also in Kenya, fide at least one mixed collection (Mathews 6433), and thus there is a strong case for treating var. pseudopaniculata as a full species. The author is confident that G. diffusa should be regarded as a well-defined local endemic species of the Somali-Masai phytochorion. At the same time the opportunity has been taken, at the suggestion of the original author, to choose a less cumbersome epithet. There is a single collection from SE Zimbabwe, Pope 795, which is superficially very similar, differing only by the unisexual flowers - the only plant seen completely lacks stamens. Most collections from southern Africa with cynose inflorescences and unisexual flowers belong to G. africana var. cymosa but Pope 795 differs from these by the filiform pedicels which are much more similar to those of the Somali-Masai species. It also differs by having only 5 mericarpsw per flower whereas most collections of G. africana var. cymosa have c. 10 mericarps per flower.
Distribution (General)
Southern Ethiopia; central Somalia; northern Kenya.A
Habitat
Acacia-Commiphora bushland, often common in more open situations where it forms an important element in the indigenous ephemeral flora, along with other Somali-Masai endemic ephemerals such as Limeum praetermissum C.Jeffrey and Bulbostylis cruciformis K.Lye.A
Habitat
Acacia-Commiphora bushland, often common in more open situations where it forms an important element in the indigenous ephemeral flora, along with other Somali-Masai endemic ephemerals such as Limeum praetermissum C.Jeffrey and Bulbostylis cruciformis K.Lye.A
Bibliography
A. Gilbert, M. G. 1993: A review of Gisekia (Gisekiaceae). – Kew Bulletin 48(2): 343-356. http://doi.org/10.2307/4117942