IJapalosiphon] xvi. sirosiphoniacejE (West). 369" 



nosis editioribus, prope Humpata, Empalanca efc Lopollo ; May 18C0.. 

 No. 15. 



4. H. WelwitschiiW. et G. S. West in Journ. Bot. 1897, p. 242. 



PuNGO Andongo. — Inter Batrachospermum grac'dUmum in rivulo de 

 Tangue ips. Prsesidii ; May 1857. No. 3. 



This species may be compared with II. hibernicus W. et G. S. West 

 (in Journ. R. M. S. 1896, 163), from which it differs in the longer 

 cells of the primary filaments ; in having much fewer branches, which 

 are also shorter and not flexuose ; moreover, the cells of the branches,, 

 as well as the heterocysts, never attain the length of those of 

 H. hibernicus. Compare also with II. intricatvs West. 



2. STIGONEMA Ag. (1824). 

 The cells of this genus are protoplasmically continuous through- 

 out the whole plant, a fine strand of protoplasm, passing from 

 cell to cell along the middle of the filament, effecting this con- 

 tinuity. This is best seen in plants that have been dried and 

 soaked out, the cells then appearing like beads on a string. These 

 connecting threads are not visible in living plants, but in becoming^ 

 dry the protoplasm shrinks away from the minute canal along 

 which it passes through the septa, and on soaking again does not 

 reattain its natural position. 



1. S. ocellatum Thur. in Ann. Sc. Nat. 6« ser. Bot. i. 380 

 (1875) ; W. et G. S. West in Journ. Bot. 1897, p. 243. 



Conferva ocellata Dillw. Brit. Conferv. 60-1, Supp. pi. d (1809). 

 Sirosiphon ocellatus Kiitz. Spec. Algar. 317 (1849) ; Tab. Phyc. ii. 

 (1850-2), 11, t. 37,f. ii. 



PuNGO Andoxoo. — A small form ; in small quantity amongst 

 Zygnema sp., growing on tufts of Scytonenia Myochrous var. choro- 

 grapMcum, on rocks on the northern and western sides of Pedra 

 Songue ; April 1857. No. 163. 



Forma majcn- W. et G. S. West in Journ. Bot. 1897, p. 243. 



A large and finely developed aquatic form. 



Hdilla. — Inter Utrieulariam, Morro de Lopollo ; April 1860. No. 

 179. In paludibus exsiccandis ; April 1860. No. 176. 



2. S. flexuosum W. et G. S. West in Journ. Bot. 1897, p. 243.. 

 HuiLLA. — Inter Hapalosiphonem luteolum et Micrnsporam Lofgrenii, 



etc., in uliginosis editioribus prope Humpata, Empalanca et Lopollo^ 

 plagas spoDgiosas unacum Eriocauloneis, Xyridibus, et Utricnlariis 

 constituens ; May 1860. No. 15. Etiam Morro de Lopollo ; May 

 1860. No. 182. 



This is distinguished from S. panniforme (Ag.) Born, et Plah. by its 

 habit, its very different branching, its almost colourless sheath with 

 smooth exterior, and by the round apices of the branches, as well as 

 by its somewhat smaller size. 



3. S. minutum Hass. Brit. Freshw. Alg. i. 230 ; ii. t. Ixvii. f. 3,^ 

 4 (1845) ; Born, et Flah. in Ann. Sci. Nat. 7« serie, Bot. v. 

 72-74 (1887); W. et G. S. West in Journ. Bot. 1897, p. 24?. 



Scytonema minutum Ag. Synop. Algar. Scandin. 117 (1817). 

 HuiLLA. — In graminosis paludibus juxta rivulum de Lopollo ; April 

 1860. No. 180. 



