May, 1906.] 
Key to Liverworts. 
535 
12. Plant green to reddish brown; leaves on the same stem hardly 
equal to each other in shape, often bearing red globules on the 
lobes of the upper leaves; perianth whitish, alpestris Schleich. 
Plant green to reddish green; leaves on the same stem similar in 
shape, often bearing vellowish globules on their lobes; peri- 
anth green to reddish. ventricosa Dicks. 
13. Involucral leaves like the cauline; leaves roundish-ovate, 2-lobed 
with obtuse sinus and inequilateral, obtuse lobes; perianth 
long-oval to pyriform. injiata Huds. 
Involucral leaves unlike the cauline; leaves 2-6-cleft or-lobed. 14. 
14. Usually purplish-black; leaves imbricate or distant on erect fer- 
tile stems with obtuse, wavy lobes; involucral leaves cristate- 
undulate, obtusely many-lobed; perianth long-clavate. 
laxa Lindb. 
Light to blackish and purplish-green; leaves horizontal or semi- 
vertical with acute or obtuse lobes; involucral leaves 3-5 cleft 
or lobed. 15. 
15. Plant small (about 2 mm.), light green often with a purplish hue; 
leaves semivertical, erect-spreading; upper involucral leaves 
longer than wide; perianth oblong, pale, often banded and 
spotted with pink. excisa Dicks. 
Plant large (5-15 mm.), deep to bluish green; leaves horizontal, 
closely imbricate, the upper wavy-crispate; involucral leaves 
wider than long; perianth oval, whitish green. 
excisa Dicks, var. crispa Hook. 
16. Underleaves none; leaves of irregular shape, .3-or more lobed with 
obtuse sinus and numerous, wide or narrow, always very 
acute, dentate lobes, thus giving the plant a crispate appear- 
ance. incisa Schrad. 
L^nderleaves present, sometimes obsolete. 17. 
17. Leaves divided to into 3 or 4 acute lobes and coarsely reflexed— 
dentate at their base; underleaves numerous, deeply bifid 
with ciliate— dentate base. sctijormis Ehrh. 
Leaves divided to yi irilo acute or obtuse lobes and not dentate 
at base; underleaves entire or 2— toothed or often obsolete. 18. 
IS. Stem often with many vertical shoots, bearing loosely imbricate 
leaves; perianth oblong. attennata Martins. 
Stem without shoots; perianth ovate. barbata Schreb. 
Kaiitia S. F. Gray. 
Without ventral runners; underleaves bifid, lobes short oval-tri- 
angular, acute or obtuse. Trichomanis S. F. Gray. 
With ventral runners; underleaves minute, the upper orbicular, 
bifid, the lower tu'ice 2-lobed, the primary lobes round-quad- 
rate, the secondary ovate or subulate SiiUivantii Underwood. 
Lcjennia Libert. 
1. Underleaves entire. clypcata Sulliv. 
L’nderleaves bifid or obsolete. 2. 
2. Underleaves bifid. 3. 
L^nderleaves obsolete; leaves muriculate-denticulate. 
calcarea Libert. 
3. -Monoecious; stem long, somewhat branching; leaves roundish- 
ovate, obtuse; perianth obovate-clavate. 
serpyllifolia Libert, var. amcricana Lindb. 
Dioecious; stem filiform, pinnately branching; leaves ovate-tri- 
angular, rounded or obtuse; perianth broadly pyriform, 
5— carinate. Plant minute. lucens Tayl. 
Lcpidozia Dumort. 
Leaves decurved, 3-4 cleft, the lobes lanceolate, formed by more 
than 2 rows of cells. reptans Dumort. 
Leaves incurved, 2-3 cleft or parted, the lobes subulate, termed 
by 2 rows of cells. sctacea Mitt. 
