272 WELWiTSCH's AFRICAN FRESHWATER ALG-E. 



laribus ; trichomatibus ©livaceo-viridibus, ad dissepimenta non 

 constriotis, apice obtuso non capitato ; cellulis diametro 9-11-plo 

 brevioribus ; protoplasmate granuloso. Crass, tot. fil. G7-10o n ; 

 crass. tricL. 17-22 jm. 



Loanda. Ad Nitellam et Najadem in lacu de Quifandougo ; 

 Dec. 1853. No. 195. 



The peculiar sheaths of this genus readily distinguish it from 

 the other genera of the Vaginanea, its nearest ally being Dasijghca 

 Thw., from which it diifers in the very firm multitubular sheath 

 with an open apex, and in the much thicker trichomes with very 

 much shorter cells. There is a very distinct line of demarcation 

 between the inner and outer constituents of the sheath, the outer- 

 most one being rendered conspicuous only by the extraneous 

 material adhering to it. The trichomes are also usually without 

 any interruption for a considerable length. 



4. MicRocoLEus Desmaz. (1823). 



1. M. VAGiNATUs (Vaucli.) Gomont in Jnurn. de Botaniq. iv. 353 

 (1890) ; in Ann. Sci. Nat. 7e serie, Bot. xv. 355-8, 1. 14, f. 12 (1892). 

 Oscillatoria vaginata Vauch. Hist. Conferv. 200-1, t. xv. f. 13(1803). 



Var. MONTicoLA (Kiitz.) Gomont in^?i». Sci. Xat. I.e. 356 (1892). 

 Crass, fil. 3-5-4-2 /x. 



Pungo Andongo. Inter Vorphyrosiplwnevi Xotarisii et Lynijhyam 

 arwjino-caruleam ; March 1857. No. 9. 



2. M. sociatus, sp. n. M. inter alias algas aquaticas repertus ; 

 fills simplicibus, elongatis et flexuosis ; vaginis firmis, hyalinis, ad 

 apicem apertis ; trichomatibus multis (9-13) intra vnginam, sub- 

 parallelis vel contortis, ad dissepimenta constrictis, dissepimentis 

 non granulosis ; cellulis diametro 2-3 (plerumque 2)-plo longioribus, 

 cylindricis ; protoplasmate granuloso ; cellula apicali acute conica 

 (diametro circiter 5-plo longiori). Crass, fil. 54-05 /x ; crass, trich. 

 2-7-3 IX. 



Huilla. Inter Schizotnchem natantem et Microspormn Lof/jrenii, 

 in uliginosis editioribus prope Humpata, Empalanca et Lopollo ; 

 May 18G0. No. 15. 



This difl'ers from M. laciistris (Eabenh.) Farlow in its narrower 

 trichomes with cylindrical cells, its acutely conical apical cells, and 

 in its firmer sheaths. 



(To be continued.) 



FERDINAND VON MUELLER. 



[It must have surprised some of our readers that no biographical 

 sketch of our valued correspondent Baron Ferdinand von Mueller, 

 who died on the 9tli of last October, has appeared in these pages. 

 The reason for the omission is, however, not far to seek. AVe had 

 hoped to have received from some Australian botanist some account 

 of the late Baron, and in that hope delayed any notice of his life 

 and work. Such account not being forthcoming, we reprint in a 



