SOUTH AFRICAN M YXOMYCETES. 



By AucisTA \'era Dutiite^ M.A. 



riic chief ol)ject uf this brief paper is to draw alteiition to 

 the South African representatives of this group, and by so doinj^ 

 to interest members of the .Association in their collection. J 

 shall thereifore luake no attempt li> ji^ive a detailed account of 

 ■the life-history of any sjiecies, nor refer to the many interestinji 

 mor{)holooical, cytolosjical and lihysiological problems connected 

 with the group which call for further investigation. But since 

 many forms are not readily recognizable as Myxomycctes by 

 laymen or botanists who are solely interested in Higher Plants, 

 perhaps I mav be excused if. preliminarily, I outline the general 

 characters. 



The -Myxomycetes. or Alycetozoa (as they are fre(|ueutly 

 termed), are lowly (Organisms which in their vegetative or plas- 

 modial >tatc reseml)le certain of the lower animals; while their 

 fruclilications and walled->|)ores, .so admirably stiited to wind 

 distribution, are >uggesii\'e rather of the fungi within the veget- 

 able kingdom. 



The naktMJ mass of proiophism formin<..;' the ))lasmo(lium is 

 ustially fotmd in decayed wodiI, on the underside of rotting 

 leaves or stems, or in the soil humus itself. The ]>lasmudiiuu of 

 Badhamia utriciihiris, which was noted in Africa for ilie lirst 

 time in njif), is excei)tional in that it feeds on tlie fructihcations 

 of living fungi. 



The extent and consistence of the plasmodiuiu may var\ 

 within wide limits. In colotu' it is usually white, yellow, or 

 pink, and it fre(|uently changes in tint as it emerges |)rior to 

 fructification. 



In the great majorit}- of .\I} .xomycetes the s])ores are formed 

 in the interior of sporangia, plasmodiocarps or a^thalia. The 

 individual sp(jrangia are usually small and \ery fragile, and 

 often of great beatity. Many of them contain an elaborate sys- 

 tem of solid or tulmlar threads — the capillitium — which is of use 

 in spore distribtition. The sporangia vary ntuch in regard to 

 shape, colour, nature (^f wall, and character of capillitium (when 

 present). 



The cethalia are cushion-like structures, consisting of densely 

 aggregated and confluent sporangia or plasmo(Hocarps. In 

 Reticularia and J'ulhjo they may be 6 cm. and 20 cm. across 

 respectivelv. Both these genera are abundant in the Stellen- 

 bosch district, and .specimens of their .ethalia are among the 

 exhibits. 



In L rralioiiiyxa — one of the commonest Sotith African 

 iforms — the oval spores are borne on the outer surface of mem- 

 braneous sporophores. 



The group is Ijy no means a large one. It comprises some 

 49 genera and about 260 species. The largest genus is Pliy- 

 sanim, with 58 species. Pidcrma comes next with 17, while no 

 fewer than 2"/ genera are re])resented by only a single species 

 each. 



