A Revision of the North American Species of Scleropodium 



By a. J. Grout 



SCLEROPODIUM Br. & Sch. Bry. Eur. 1853 



Closely allied to Brachythccium and included in it by some 

 authors ; differing slightly in the general habit and in the julaccous 

 branches with concave, often obtuse leaves ; leaf cells very long 

 and narrow, 10-20 : i. Stem leaves abruptly and slenderly acu- 

 minate in most species. Seta rough ; capsule as in Brachythccium. 

 All of our species are western. 5. illeccbrum and 5. caespitosum 

 are also European. 



I. Leaves broadly ovate to suborl>icular, without pointed apex or at most short-cuspi- 

 date ; auricles distinct, consisting of plainly dilated cells ; aquatic. 



S. obtii'ifoliiaii. 



Leaves ovate to lanceolate ; stem leaves slenderly acuminate, without distinct 



auricles ; terrestrial. 



2. 



2. Leaf cells 14-18 : I, differentiated basal and alar cells few. ' 3- 



Leaf cells 7-12 : I, differentiated basal and alar cells in several rows. 4. 



7 Branch leaves ovate-lanceolate to lanceolate, acnte to acuminate ; capsules sub erect 



, ■, , ■ S. colpopbyllttm. 



and nearly symmetric. 1 



Tkanch leaves ovate to oblong-ovate, obtuse to abruptly short-acummate ; capsules 



hori7.ontal and unsymmetiic. ' 



4 Brandies slightly julaccous ; capsules suberect and nearly symmetric. 



S. caespitosunu 



Branches strongly julaccous ; capsules more arcuate and unsymmetric. 



S. apocJaduni. 



This genus is perhaps too near Brachythccmm and one species 

 referred to it by most authors (5. Californicum) is most certainly 

 a Brachythccium. The relationship with Eurhynchium is much 



more distant 



Ipophylhu. 



species is hard to understand when one has a large series of plants 



for comparison. The relationship between :>. coipophylL 

 caespitosum is so close that about half the specimens of t 

 in American herbaria have been referred to the latter. 



I am greatly indebted to the United States National 

 Harvard University, The University of Wisconsin, and Mr. J. M. 

 Holzinger for the loan of specimens. The work has been largely 



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M 



