WELWITSCH S AFRICAN FRESHWATER ALG^. 6 



primarii longis et uumerosis, iis ordinis secundi brevibus sparsisque ; 

 axe primario e seriebus multis uuiformibus parallelis cellularum 

 elongatarum constituto, leviter dilatato ad nodos; ramulis laterali- 

 bus brevibus uniformibusque, nonnullis leviter ramosis, per axem 

 totum regulariter (et non dense) dispersis ; fasciculis densis globosis 

 magnis ramnlorum ramosissimorum e nodo bine inde (3-5 ram.) 

 ortis. Diam. fil. prim. (c. ramul. lat.) 150-166 //, ad nod. 250- 

 275 fji ; diam. ax. fil. prim. 42-59 fj., ad nod. 66-91 /x ; diam. fascic. 

 glob, ramul. 208-480 /x. 



Pungo Andongo. Ad lapides submersas in rivulo de Tangue; 

 May 1857. No. 3. 



This very beautiful species is characterized by its numerous 

 elongate and delicate branches, which bear the short uniform lateral 

 branches evenly without interruption along their whole length. The 

 globose clusters of lateral branches, which are developed on every 

 7th to 12th node, are no doubt connected with the fructification ; 

 their terminal cells are of a different form to the others, being 

 larger and mostly subglobose. The axis of the filament does not 

 pass through the centre of this dense mass of branches, but the 

 attachment of the globular mass is at one side of the node from 

 which they arise. 



4. B. huillense (Welw. MS., name only). B. subradiatum, 

 in vivo hiete viride, extra aquam mox violaceum, exsiccata nigresceus ; 

 fila primaria rubra, dense ramosa ; ramis ordinum trium vel quat- 

 tuor, ultimis plerumque geminatis, brevibus et confertissimis, brevi- 

 oribus apices versus ; axe primario e seriebus parallelis numerosis 

 appositis cellularum formato serie centrali cellularum multe 

 majorum ; ramulis lateralibus brevibus deusisque plus minusve 

 uniformibus, ad nodos densioribus, axe juxta supra nodos sub- 

 glabro; ordine iutermedio ramornm submouiliformi, ramis juveui- 

 bns nodis approximatis submoniliformibusque. Diam. fil. prim, 

 (c. ramul. lat.) 191-325 //, ad nod. 275-400 /u.; diam. ax. fil. prim. 

 125-275 /x, ad nod. 175-325 fx. 



Huilla. Freq. ad riipes lapidesque submersas in rivulis prope 

 Lopollo; May 1860. No. 4. Also fragments from No. 187. 



This species is well marked by its peculiar and dense branching, 

 specimens dried on paper appearing hypnoid. It reminds one of a 

 delicate B. atnun Harv., except as to its branching. This species 

 and B. ijracilliinuin adhere very well to paper, while B. nujrescens 

 and B. aiujolense adhere but slightly. 



II. HiLDENBRANDTIACE.E. 



1. HiLDENBRANDTiA Nardo (1845). 



1. H. RivuLARis (Liebm.) J. Ag. Species Ahjar. ii. 495 ; Eabeuh. 

 Fl. I'Au-iip. Ah/, iii. 408. Diam. cell. 3*5-4 /x. 



Goluugo Alto. Macalis magnis belle sanguiueis rupes siliceo- 

 arenosas juxta Fontem de Capopa oruat ; Sept. 1855. No. 149. 



2. H. ANGOLENsis Welw. MS. ; name with partial description ; 

 the following description is ours : — 



B 2 



