NEW BRITISH MOSSES, 175 
absence of radicles on the stem ; while the striated leaves of 
H. fluviatile, their looser texture and far stouter nerve, afford 
characters sufficiently distinctive. 
6. Hypnum polymorphum, Hedw. *'Trunco tenui, bifariam 
ramificato; ramis subsimplicibus; foliis eductulosis, ex 
ovato longe acuminatis, semper patentibus varie direc- 
tionis, Sporangiis cernuis, operculo conico." Spec. Musc. 
p- 259, t. 66. 
H. stellatum, var. y, Bridel Bryol. univ. p. 602. H. Som- 
merfeltii, Myrin in Herb. Hook. (fide Wilson). : 
Han. On wet limestone at Crambeck, and on the ruins of 
Kirkham Abbey, in the Vale of the Yorkshire Derwent; 
the fruit-mature in May. 
That the Hypnum polymorphum of the * Muscologia Bri- 
tanniea" is distinct from the species of Hedwig (which is 
figured and described with a nerveless leaf) has always been 
maintained by continental botanists, and Bridel in the ** Bryo- 
logia Universalis” has referred it to his H. chrysophyllum. 
To me it appears a mere variety of H. stellatum, as indeed 
Hooker long ago suspected (see * Eng. Flora," vol. V, part I, 
P- 90). In a specimen of H. stellatum given me by Mr. Bor- 
rer from Schimper’s “ Bryologiæ Europææ Stirpes Normales,” 
I find nerved and nerveless leaves even on the same branch 5 . 
and in Ascham Bogs, near York, the large form of that spe- 
cies frequently shows leaves nerved almost quite to the sum- 
mit. Besides, in undoubted examples of H. polymorphum, 
H. and T., the nerve is sometimes short and forked, and not 
seldom altogether wanting; and Dr. Taylor has remarked to 
me, “J find a specimen sent to me of H. chrysophyllum by 
unze (a most accurate muscologist) to have leaves inter- 
mediate, especially as to the nerve, between H. stellatum and 
 polymorphum Now as no other character has ever 
n insisted on for the separation of these two than the 
nerved leaves of the latter and the nerveless ones of the 
former, and experience has amply shown the invalidity of 
this difference, I feel quite justified in considering them forms. 
of the same species, | 
