523 
identical with the Jungermannia platyphylloidea of Schweinitz, of 
which we have seen authentic specimens both in his own her- 
barium preserved at Philadelphia and in that of Torrey at Co- 
lumbia University. The more common European form of 2 
platyphylla, marked by irregular branching, yellower color, ob- 
liquely ovate dorsal tubes with the superior margins ascending or 
reflexed, and by the obliquely ovate ventral lobes, which are only 
about half as wide as the underleaves, is rare in America, but as 
such may be cited specimens collected by Mr. Faxon on Owl’s 
Head, Canada (near Lake Memphremagog), June 27, 1885, and 
by Professor Underwood at West Goshen, Conn., July, 1887, and 
at Natural Bridge, Va., Sept., 1887. Transitional conditions occur 
so frequently that we believe nothing is gained by an attempt at 
separation. 
6. PorELLA Navicucaris (Lehm. et Lindenb.) Lindb. Act. Soc. 
Scien. Fenn. 9: 337. 1869. 
Jungermannia navicularis Lehm, et Lindenb. in Lehm. Pugill. 
6: 38. 1834. 
Madotheca navicularis Nees, G. L. N. Syn. Hep. 277, p. p. 
1845. 
Shining or more rarely dull, brownish-yellow, large: stems 
somewhat regularly bipinnate, 4-12 cm. long, procumbent-caespi- 
tose, or subpendulous with apices ascending when moist, branch- 
lets gradually narrowed, subacute, convex on drying and slightly 
deflexed : dorsal lobes of leaves densely imbricate, appressed, for 
the most part closely wrapped about the stem when dry, obliquely _ 
Orbicular-ovate to ‘oblong-ovate, 1.2-2.5 mm. x I-1.8 mm., 
rounded-obtuse, apex decurved, subcucullate, inferior margin 
slightly undulate-crisped, the superior decurrent, its wing some- 
times laciniate-crispate, otherwise very entire, the inferior basal 
angle composed of numerous small thick-walled cells 4-™% the 
diameter of the remainder, trigones conspicuous throughout ; ven- 
tral lobes ovate, obtuse, most rarely subacute, regularly rounded © 
outwardly at base, .5—1 mm. x.33—.75 mm., a little smaller than 
the underleaves, length somewhat more than ¥%4 the width of the 
dorsal, margins entire, recurved, decurrent, apex often deflexed ; 
underleaves approximate, quadrate-oblong, rounded-obtuse, mate: 
gins entire, recurved, long-decurrent, apex occasionally deflexed e* 
dioicous : $ branches oval to oblong, 114-2%4 mm. in length i 
