200 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 



forma obliquum (Muhl.) Fernald. — (B. obliquum Man. ed. 7 and 

 111. Fl. ed. 2; rid. Rhodora, 23: 151, 1921.) 



Fields, hillsides, pastures and open woods ; frequent. 



B. ramosum (Roth) Aschers. — (B. negledum 111. Fl. ed. 2.) 



Rich leaf mould, chiefly under deciduous trees, often associated 

 with B. angusiisegvicntum; frequent. 



B. simplex E. Hitchcock. — New Ashford, in pastures not far from 

 brook (Andrews); Washington (C. S. Lewis); rich woods. Stock- 

 bridge; Sheffield (Churchill). 



B. ternatum (Thunb.) Sw., var. intermedium D. C. Eaton. — 

 {B. silaifolmm 111. Fl. ed. 2.) 



Pastures and open woods; frequent. 



B. virginianum (L.) Sw. Rattlesnake Fern. — Rich woods; 

 common. A plant from Florida has the fertile segment divided into 

 two full-sized divisions. 



var. intermedium Butters. — {B. virginianum Man. ed. 7 in part.) 



Dry, rocky upland woods. North Adams (Fernald and Long). 



Botrychium virginianum, var. intermedium has lately been dis- 

 tinguished from the type {vid. Rhodora, 19: 207, 1917). 



Ripe sporangia straw-colored, opening but slightly in dehiscence, their walls 

 composed of regular cells; pinnules of the sterile frond ovate to lance-ovate, 

 their ultimate segments spatulate B. virginianum, var. intermedium.. 



Ripe sporangia brown, opening rather widely in dehiscence, their walls 

 composed, at least in part, of irregular cells with sinuous walls; pinnules of the 

 sterile frond much dissected, lanceolate, deeply pinnatifid or nearly pinnate, 

 and the ultimate segments oblong or cuneate or decurrent at the base, lanceo- 

 late and scarcely or not at all spatulate B. virginianum. 



OPHIOGLOSSUM. Adder's Tonglte. 



O. vulgatum L. Adder's Tongue. — Mucky pockets in low 

 meadows; frequent. In thin soil on a limestone outcrop in Great 



Barrington. 



MARSILEACEAE. 

 MARSILEA. 



M. QUADRiFOLiA L. — A small colony in the inlet to Prospect Pond, 

 Egremont. An interesting European aquatic often cultivated and 

 probably introduced, perhaps accidentally, at the above station. 



