246 BULLETIN OF THE UNIVEESITT OF "WISCOiSSIN. 



Acute or short apiculate, alar cells few, large . H. palustre, 398. 

 Obtuse, entire, alar cells hyaline . . . H. caspidatum, 403. 



2. Alar cells scarcely different or quadrate or rectangular, not 

 abruptly enlarged. 



* Leaves thin, glossy, open; plants mostly small, prostrate or with 

 ascending branches. 



Leaves squarrose, acuminate. 

 Sub-serrulate all around, lid apiculate . . H. hispidulum, 378. ^ 

 Entire except the acumen, lid obtuse . . H. Maconnii, 539. 



Leaves loosely imbricate, obtuse or acute. 

 Serrulate, at least above. 

 Nearly as broad as long, obtuse or apiculate. 

 Alar cells small, not forming distinct auricles, 



others 1 : 8-10 H. moUe, 399. 



Alar cells large, forming distinct auricles, others 



much longer than preceding . . H. dilatatuui,^ 601. 



Nearly twice as long as broad, acute, point often halt 



twisted H. alpestre, 399. 



Entire. 

 Leaves close set, ovate (1:2). . . . H. Norvegicum, 681. 

 Leaves more distant, rotund .... H. Ooulardl, 685. 



* * Leaves firm; plants very large, mostly IS pinnate, erect 

 or ascending. 

 Paraphyllia none. 

 Capsule smooth when dry. 

 Leaves obtuse. 

 Olive or grayish green, 1-2-pinnate, leaves open H. Schreberi, 40i. ' 

 Dirty green to dark brown, almost simple, leaves 



closely appressed H. trifarium, 405. 



Leaves abruptly apiculate, plants pale green . . H. puruin, 594. 

 Capsule plicate when dry, plants dark green to reddish 



brown H. scorpioides,* 406. 



Capsule unknown; plants dark yellow and greenish, branches 



julaceous, few, fastigiate, leaves short apiculate H. tur^escens, 406. 

 Paraphyllia present H. Alaskannm, 405. 



1 S. circulifolium, C. M. & Kindb., Appendix, uo. 583, belonging to this division and de- 

 scribed from sterile specimens, is related to H. dilatatum Wils. 

 ^ See Appendix, no. 599. 



