VAUCHERIACE^E. 123 



Plate XLV1I., figs. 9, 10. Oogonia and antheridia of V. Dillwyni x 

 200. Fig. 11. Oogonium of the same X 200. Fig. 12. Mature oospore 

 enclosed in membrane of oogonium X 230, after Walz. Fig. 13. Sper. 

 matozoids. 



5. Vaucheria sessilis. Vauch. Conf. p. 81. pi. 2, /. 7. 



Loosely intricate, pale or rather dull green. Thallus capil- 

 lary, sparingly branched ; oogonia 2 to 3 approximate, rarely 

 single, ovate or oblong-oval, more or less oblique, rostrate ; 

 antheridia intermediate, either short, hamate, or straight and 

 subulate, or a little clavate, sometimes elongated and in- 

 curved, rarely circinate. Mature oospores punctate with 

 brown, involved in a triple membrane. 



SIZE. Oospore -07 mm. diam., thread -07 mm. (Cleve). 



Eng. Fl. v., 320. Cleve Vauch. 133, f. 6. Kirsch Alg. 

 Schl. 82. Walz Vauch. p. 145. Kutz. Tab. vi., 59, f. 2. 

 Hass. Alg. t. 4,' f. 2. Eng. Bot. t. 1765. Harv. Man. p. 148. 

 Grev. Alg. Br. p. 192. Jenner Tunb. Wells 176. 



Vaucheria splicer ocarp a, Kutz. Tab. vi., t. 59, f. 1. 



Vaucheria racemosa, Rabh. Alg. Sachs. No. 495. 



Vaucheria Ungeri, Thur. Ann. Sci. Nat. xix. (1843), t. 11, 

 12, 13, f. 37-42 and 44. 



Sporangia. 



Vaucheria clavata, Vauch. Conf. t. 3, f. 10. Hass. Alg. 

 59, t. 2, f 20-33. Harv. Man. 149. Berk. Glean, t. 10. 

 Gray. AIT. i., 290. 



In ditches, or on the ground. 



var. a. caespitosa. Vauch. Conf. p. 26, t. 2, /. 4. 



Oogonia usually in pairs, ovate, opposite. Antheridia in- 

 termediate, generally short, circinate. 



Vaucheria ccespitosa, Garni. Eng. Fl. v., p. 321. Eng. Bot. 

 1, t. 2841, ii., t. 2421. Hook. Fl. Scot, ii., 92. Jenner 

 Tunb. Wells, 176. Grev. Alg. Britt. 194. Harv. Man. 148. 

 Johnst. Fl. Berw. ii., 251. Hull Br. Fl. 330. Abbot. Bedf. 

 275. Mack. Hib. 234. Gray Arr. i., 291. 



Conferva amphibia, Dill. Conf. t. 41. With. Arr. iv., 129. 

 Ends. Fl. Aug. ii., 594. Lightf. Fl. Scot. 979. Sibth. Ox. 

 336. 



Conferva amphibia fibrillosa et spongiosa, Dill. Muse. t. 4, f. 17. 



Conferva terrestris exilis fibrillosa, Ray. Syn. 59. 



On the margins of streams or pools. 



" Fronds densely interwoven into cushion-like tufts or strata of in- 

 definite extent, irregularly branched, the tips erect, giving the surface, the 

 appearance of bright green velvet." Harvey. 



Dillwyn's description of his Conferva, amphibia seems to be most appli- 

 cable to this species. " On the edges of ditches, and in similar situations, 

 it frequently occurs in masses so densely matted as to hold water like a 



