WELWITSCH's AFRICAN FRESHWATER ALG^. 41 



4. 8. NEGt.ECTA(H.ajSS.)Iintz. Species Algar. HI {I8i9) ; Eabenh. 

 Fl. Eurup. Alijar. iii. 248 ; Petit, Spirori. \le Paris, 26, t. ix. f. 1-5. 

 Zygnema neylecta Hass. Brit. Freshw. Alrj. 142, t. 23, f. 1-2 (1845). 



Var. TERNATA (Ripart). .S'. ternata Ripavt iu Bull. Soc. Bot. 

 Fr. xxiii. 162 (1876); Petit, I.e. 26, t. viii. f. 4-7. S. ternata 

 Ripart seems to us to be but a variety of S. neylecta, differing only 

 in its inflated fructiferous cells. The length of the cells agrees in 

 both. Cfr. also W. & G. S. West in Journ. lint, xxxiv. 378 (1896) ; 

 crass, cell, veget. 52-57 jm. ; long, zygosp. 107-127 i^, lat. 68-67 /*. 



Huilla. Frequentissima post pluv. autumnal, ad margines rivu- 

 lorum prope Lopollo ; April, 1860. No. 185. 



5. Spirogyra sp. CellultB vegetativfe diametro (52-61 fji.) l|-2- 

 plo longioribus, extremitatibus non replicatis, chromatophoris 3, 

 anfractibus 1^-2. 



Pungo Andongo. Inter BatracJiuspenmua niqresccns in riv. 

 Ciiauza ; March 1857. No. 104. 



6. S. angolensis Welw. MS. (name with partial description). 

 S. nubeculiformiter cresceus, mox subuatans, sordide viridis, adulta 

 fuscescens ; cellulis vegetativis diametro 1-2-plo longioribus, ex- 

 tremitatibus non replicatis ; chromatophoris 2 (raro 3), latis cum 

 marginibus asperis et pyrenoidibus magnis, anfractibus 2-3 ; fila- 

 mentis fractiferis atro- vel fusco-purpureis, rigidis, cellulis fructiferis 

 non inflatis (vel leviter subintiatis) ; zygosporis magnis, psene 

 cellulas complentibus, ellipticis cum apicibus subacutis, diametro 

 1^-lf-plo longioribus. Crass, cell. veg. 49-63 ^ ; long, zygosp. 

 84-100 fj,, lat. 52-57 /^. 



Loanda. Cum Octogonis aequinoctiali in aquis stagna puris 

 (Cazimba) urbis Loanda; June 1858. No. 124. In stagnis arti- 

 ficialibus (Repressas) circa Loandam ; July 1854. No. 193. Etiam 

 No. 103. 



The very dark-coloured conjugating filaments and the form of 

 the zygospores cliaracterize this species. S. arcta (Ag.) Kiitz., to 

 which No. 193 was referred by Welwitsch, is a much smaller plant 

 with but one chromatophore, and the conjugating filaments are not 

 dark- coloured. 



7. S. Welwitschii, sp. u. S. cellulis vegetativis diametro 

 ^-2-plo longioribus, extremitatibus non replicatis ; chromatophoris 

 2 (raro 3), magnis, cum marginibus serratis et pyrenoidibus magnis, 

 anfractis arctis, 1-2 ; cellulis fructiferis non inflatis ; zygosporis 

 late ellipticis, diametro l^-plo longioribus, cellulas fructiferas non 

 complentibus. Crass, cell, veget. 65-75 ^ ; long, zygosp. 69-71 fji., 

 lat. 57-58 (A.. 



Loanda. " Sp. dense agmine crescens, nubecularum amoeniss. 

 virid. ad instar aquis innataas ; in stagnis artificialibus circa 

 Loandam" (c. S. a)iyolensi Welw.); July 1854. No. 103. 



This species approaches .S'. deciinina (Miill.) Kiitz. (to which 

 Welwitsch had referred it) and S. neylecta (Hass.) Kiitz. ; it differs 

 from the former in its much greater thickness, shorter cells, and 

 larger zygospores ; from the latter in its somewhat thicker filaments, 

 shorter cells, the character of its chromatophores, and in its shorter 

 zygospores. 



