54 THE FLORA OF NEBRASKA. 



Vancheria aversa Hass. Brit. F, W. Alg. 54. 1845. 



Loosely cespitose, sparingly branched; oogones erect or suberect, almost 

 always twin, sessile or subpedicillate; antherids cylindrical or subclavate, 

 erect, ends more or less curved; filaments 75-95 /i in diam., oospores very 

 granular, 95-105x60 //. 



In creeks about Lincoln. PL XIII., Fig. 2. 



Vancheria sessilis (Vauch.) DC. Flor. Franc. II, 63. 1815. 

 Ectosperma sessilis Vauch. Hist. Confer. 31. 1803. 



Loosely intricate, pale or dull green; thallus capillary, sparingly branched: 

 oogones 2 or 3 approximate, rarely single, ovate or oblong-oval, more or 

 less oblique, rostrate; antherids either short hamate, or straight and 

 subulate, or a little clavate, sometimes elongated and incurved; mature 

 oospore punctate with brown, involved in a triple membrane; vegetative 

 filaments 50 65 fi in diam., oogones 105x60 p. 



Very common in streams and on damp earth throughout the state; also in 

 greenhouses. PL XIIL, Fig. 1. 



Vancheria gem inata (Vauch.) DC. 1. c. 62. 



Ectosperma geminata Vauch. 1. c. 29. 



Pale or dull green, thallus capillary, tenacious, 30-90 /i broad, dichotomous; 

 oogones 2, rarely 1 or 3, ovate or oblong, opposite, distinctly pedunculate; 

 antherids intermediate, subulate, more or less curved; mature oospore 

 spotted with brown, spore-wall colorless, of three layers; filaments 55-120 

 l-i in diam. 



Vae. — raceniosa Walz. in Pringsh. Jahrb. 1866, p. 112.— Oogones short pedunculate, 

 3-5, sometimes 8-10 aggregated in a corymbose manner; antherids single, 

 scarcely longer than the oogones. 

 Creeks, Lincoln. Not common. PL XII., Fig. 3. 



Vancheria tnberosa A. Br. in Kuetz. Tab. Phyc. VI, 23. 1815. 



Flagella subterranean, apices swollen tuber-like; filaments filled with starch 

 granules, dichotomously branched, 3 or more times divided; branches 

 constricted at the base and occasionally intermediately, constriction 

 reddish; filaments 60-100 [i in diam.; antherids and oogones have never 

 been found. 

 In a sandy creek near Lincoln. PL XII., Fig. 2. 



Vancheria terrestris Lyngb. Hydroph. 77. 1819. 



Oogones single or often in clusters, pedunculate, attached to the back of the 

 elongated, curved antherid; mature oospore enclosed in a colorless 

 epispore composed of 4 inflated membranes which are diffluent in water. 



Forms densely interwoven, dark green strata on moist earth. 



Minden. PL XIIL, Fig. 3. 



Family. -HYDROGASTRACEAE. 



Thallus small, unicellular, terrestrial, green, globose, attached to moist earth by 

 hyaline, much branched rhizoids. Propagation by unicellular zoogonidia or by sub- 

 division of the whole plant. Reproduction by the copulation of sexual zoospores, pro- 

 ducing asexual zoospores which form a vegetative plant; the cell contents of the latter 

 divide into an indefinite number of resting spores which produce microgonidia. 



