May, 1906.] Key Jo Liverworts. 531 



4. Thallus simple or slightly lobed; involucre short, lacerate; pedicel 



not folded upon itself. pingiiis Duniort. 



Thallus irregularly lobed; involucre none; pedicel 16-25 mm. long, 



SDmetimes folded upon itself and remaining within the cal- 



yptra, the capsule thus appearing sessile. sessilis, Spreng. 



.\ iillioccros Micheli. 



Thallus papillose; spores black, strongly muriculate and sharply 



angled. punctatiis L. 



Thallus smooth; spores nearly smooth, yellow, angular, lacvis L. 



Astcrella Beau v. 



Thallus forking and increasing by joints. Antheridia in sessile 

 lunate disks. Peduncle bearded at base and apex. Spores 

 large, tuberculate, nearly reticulately folded. 



hemisphaerica Beau\'. 

 Bazzania S. F. Gray. 



Plant robust; leaves from green to brownish, about 2 mm. long, 

 somewhat deflexed with concave base, their apex 3-toothed; 

 underleaves roundish— quadrangular, 4—6 toothed above and 

 sinuate on the sides. trilobata S. F. Gray. 



Plant much smaller; leaves yellowish or dark brown, about 1 mm. 

 long, strongly deflexed, perfectly convex, their apex 2-3 

 toothed rv entire; underleaves suborbicular, bifid, crenate or 

 entire. deflexa Underw. 



Blasia Micheli. 



Thallus simple or forked or stellate, with sinuous margin; fruit 

 from an oval cavity in the costa; involucre mostly none; 

 capsule oval-globose; gemmae globose in flask-shaped recep- 

 tacles; the scale- like underleaves broad-oval, coarsely dentate, 

 in one longitudinal row. pusilla L. 



HUpliarostoma Dumort. 



Stem flaccid, creeping, branched; leaves much smaller than the 

 ramose, forking and awl-shaped involucral leaves; perianth 

 ovate-cj'lindric. trichophylliim, Dumort. 



Ccphalozia Dumort. 



1. Perianth more or less 3-angled or 3-carinate; leaf cells large 



(mostly 25-50 /a broad;) plants medium sized. 2. 

 Perianth 3-6 angled; leaf cells small ( 1 4-20 /£ broad) ; plants small, 

 often minute. 7. 



2. Underleaves rarely present, except on fruiting branches. 3. 

 Underleaves usually present; leaves rarely subimbricate. 



fluitans Spruce. 



3. Leaf lobes straight. 4. 



I^eaf lobes connivent or incurved. . 5. 



4. Dioecious, rarely monoecious; without runners; usually pale; leaf 



cells opaque; perianth large, widest above middle, unequally 

 ciliolate. virginiana Spruce. 



Monoecious; with runners; usually greenish or reddish; leaf cells 

 pellucid; perianth linear-prismatic or fusiform, whitish, den- 

 ticulate or ciliate. biciispidata Duniort. 



5. Leaflobes narrow, incurved. curvifolia Dumort. 

 Leaflobes broad, short, connivent. 6. 



6. Leaves deucrrent; perianth linear-fusiform, 3-plaited, when young 



triangular only above, when mature. multiflora Spruce. 



Leaves not decurrent; perianth large, oblong-cylindric, obtusely 



angled. planiccps Underwood. 



7. Growing on the ground and on rocks; heteroecious; perianth linear 



or narrowly fusiform, prismatic, denticulate or subentire; 

 leaves somewhat distant with acute lobes and an almost rec- 



