184 



The N.a.tuealtst. 



21. Plagiotheciurti sylvaticum. L. Near Pannal, W. West, fide H. 

 BoswelL Wood opposite Woodhall, near Collingham. Wetherby, 

 Dr. Wesley" — C. P. H., in Jour. .Bot., Dec, 1879. I confess to 

 not clearly differentiating this from large, distant-leaved infertile 

 examples of F. denticulatum mitil recently, when I became the 

 recipient of opinions on the matter from Dr. Spruce and Mr. 

 Boswell. Too many moss-lovers, myself amongst them, too often 

 fail to give their first and closest attention to the characters 

 afforded by the inflorescence. P. sylvatioum is dioicous ; and, 

 apart from its greater rarity than P. denticiilatiim, in consequence 

 fruits less frequently ; though when it does, the long rostrate beak 

 of the capsule at once reveals it ; but when without inflorescence it 

 is no easy matter to tell one species from the other, Mr. Boswell 

 remarks that " sylvaticum may be known by the larger areolae of 

 the leaves, by their stronger nerves, and (I presume he means when 

 in process of drying) by the shrinking of the foliage," making 

 them look more distant. So far as my observation goes, P. sylva- 

 ticum, when growing, is of a much deeper, richer green (often with 

 a tinge of golden-brown in it) than its monoicous double, and in 

 drying for the herbarium loses its glossiness, becoming dull and 

 opaque, the leaves disposing themselves naturally in two opposite 

 ranks with a loss of contiguity. P. denticulatum varies much, and 

 there is a distant-leaved variety, but has evident complanate leaves 

 inclined to overlap, their edges recurved, and of a paler green, with 

 a high gloss not lost in drying. The dates given in manuals for 

 the fruiting of the respective species need revision. P. sylvaticum 

 is said to fruit in autumn, and denticulatum in spring ; but I have 

 seen not over-ripe capsules of P. sylvaticum — as determined by 

 better " authorities " than I lay any claim to be — gathered near 

 here and at Castle Howard in February, April, and May of this 

 year ; whilst P. denticulatum is in like good condition at the same 

 time about here. It would be more correct to regard both species 

 as summer fruiters, as John Nowell long ago stated. 



22. Hypnum aduncum, Hedw. {Kneifiii, Schimp. Syn.) In plenty in 

 two marshy fields near the cemetery on left of Walton Road, 

 Wetherby. A curious drawn-out form without the strongly- 

 hooked stem and branch apices usual in Kneifii, but with the 

 characteristic enlarged quadrate cells at the decurrent alar angles 

 of the leaves. 



23. H. vallisclausce, Schpr. In the water of a rill in rushy field near 

 Stockeld Grange Farm ; discovered by Wesley, but not in his list. 



