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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



[VOL. 11 



ments short; leafy stems complanate; dorsal cortical cells of 

 the stem between the 2 rows of leaves very large, inflated; 

 rhizoids from the ventral side of the stem or from the surface 

 of the caudex. Alobiella. p. 378 



9. Leaves bifid (occasionally trifid) to one-half their length, 

 underleaves bifid (some trifid) to the middle. 

 10. Underleaves with a conspicuous lateral tooth midway on 

 both sides; branches only ventral-intercalary, leafy or 

 flagelliform ; leafy stems appearing flattened. 



Cladomastigum. p. 382 

 10. Underleaves without lateral teeth ; branches both lateral 

 and ventral ; rhizoids in tufts, from the underleaves or in 

 3 rows on the flagelliform branches or caudex. 

 11. Ventral branches of the leafy stem always axillary- 

 intercalary, leafy or flagelliform ; leafy stems often ap- 

 pearing flattened, often from a prostrate caudex; 9 

 inflorescence on a very short branch from the caudex. 



Leucosarmentum. p. 386 

 11. Ventral branches of the leafy stem both of the Acro- 

 mastigum type, with a half-underleaf adjacent to the 

 branch, and axillary-intercalary, leafy or flagelliform. 



Paracromastigum. p. 389 

 Underleaves reduced to 1 (rarely 2) rows of 2 to 4 adjacent cells 

 across the stem, with or without 1 or 2 rudimentary segments; or 

 few-celled, scale-like ; or as 1 or 2 slime papillae, soon disappearing. 

 8. Underleaves of 1 (rarely 2) row of 2 to 4 adjacent cells with 

 or without 1 or 2 rudimentary segments; rhizoids from the bases 

 of the underleaves. 



9. Underleaves usually with 1 or 2 rudimentary segments; leaves 

 bi-, tri- or quadrifid to the middle; leaf segments uniseriate, 

 soon broken. Odonto series, p. 364 



9. Underleaves without segments; leaves bifid. 



10. Leaves obliquely inserted, Cephalozia-like, slime papillae 



when present small. Regredicaulis. p. 358 



10. Leaves sublongitudinally inserted, the two "slime" papillae 



very long, sausage-shaped, persistent. Zoopsis. p. 368 



8. Underleaves few-celled, scale-like, or absent; rhizoids from the 



ventral surface of the stem. 

 3. Plants some shade of brown, tinged with brown, or becoming 

 reddish. 



10. Plants coarse or delicate, often stiff, brownish-green to 

 yellow-brown or straw-colored. 



11. Leaves subquadrate, retuse, coarse; cells with many 

 bands of thickening over the surface ; cuticle coarsely 

 roughened. Trabacellula. p. 3S2 



11. Leaves bifid. 



12. Leaf segments short, triangular, acute. 



Fuscocephaloziopsis. p. 353 

 12. Leaf segments slender, long-acuminate; ventral side 



of leaf forming an inflated sac. Nowellia. p. 326 



10. Plants slender, often flaccid, reddish-brown to reddish. 

 11. Leaf segments slender, long-acuminate; ventral side of 



the leaf forming an inflated sac. Nowellia. p. 326 



11. Leaf segments acute, or acuminate by only 2 cells; 

 leaves concave, cup-shaped or variously twisted, never 

 with a ventral sac. Cephalozia. p. 311 



9. Plants green, whitish, or light yellow-green, only rarely tinged 

 with red or brown at the tip. 



10. Leaves with the ventral side forming a conspicuous in- 

 flated sac. Nowellia. p. 326 



10. Leaves plane or variously concave or twisted but never 



with a ventral sac. Cephalozia. p. 311 



