242 ORTHOTRICHACEiE. 



gradually tapering to the neck, usually a little larger and of 

 slightly firmer texture. 



Var. y. crispula Hamm. (Ulota crispula Bruch). Smaller, 

 leaves shorter. Capsule very small, oval or sub-globose, with a 

 long neck ; when dry and. empty very pale and thin-walled, 

 somewhat turbinate, wide-mouthed and not or hardly constricted 

 below, rather abruptly narrowed into the neck. 



Hab. Trees ; common, especially in damp mountainous woods. The var. /3. 

 often mixed with the type and apparently equally common. The var. 7 in similar 

 situations but rare. 



A very pretty moss, its neat rounded cushions usually covered with capsules ; 

 these vary much in size, form and texture, and their shape depends much upon their 

 age and upon the degree of moisture ; before the fall of the lid they are green, oval, 

 and suddenly contracted into the long tapering neck ; but when they become perfectly 

 matured, and are emptied of their spores, they are, when dry, narrower, paler, and 

 contracted below the mouth ; after maturity they undergo another change, growing 

 darker in colour, and narrower, often becoming finally narrowly cylindrical or fusi- 

 form ; in the early stages, as well as in the later, they are difficult to distinguish from 

 some of the other species, and dry, well ripened, but not over-ripe capsules should be 

 chosen for examination. 



If good typical tufts of U. crispa and the var. intermedia are examined, the 

 difference in form of the capsules is very marked, the latter being in no way urceolate, 

 but exactly of the same width at the mouth as below. It is however comparatively 

 rarely that perfectly typical capsules of either are met with ; this being especially the 

 case with the var. intermedia ; on the contrary more often than not some at least of 

 the capsules on a tuft show a very slight contraction below the mouth, while on the 

 other hand the typical, distinctly urceolate form of capsule of U. crispa is less 

 frequently met with than a somewhat less distinct form, markedly, but less strongly 

 constricted. It is impossible therefore, to maintain U. intermedia as an independent 

 species, and it should perhaps be looked upon rather as a variety only, although it 

 must be admitted that U. Bruchii is almost universally admitted as a species on the 

 basis of characters not very much more important either in quality or in degree. 

 Similar remarks apply to the var. crispula, and the two varieties may in some degree 

 be considered as the two extreme limits, the one more robust, the other more slender, 

 of a fairly well graduated chain of forms of which the type occupies the middle 

 position. On the other hand forms referable to the var. crispula in size of capsule, 

 general slenderness, etc., sometimes in the shape of the capsule resemble the var. 

 intermedia rather than the type, and thus establish a separate chain of forms. 



In the var. crispula as the fruit becomes old the capsule narrows, the transition 

 to the neck becoming less abrupt, until finally the whole becomes narrowly oblong, or 

 gradually tapering from the mouth to the neck, and in these states the resemblance, 

 in miniature, to the var. intermedia is very pronounced. I have indeed seen on the 

 same tuft capsules exhibiting a great variation in size, some of which would be quite 

 inseparable from the var. intermedia. In some parts, at least, of Canada, judging 

 from numerous specimens I have received, the two varieties would appear almost to 

 supersede the type. 



5. Ulota calvescens Schp. (Orthotrichum calvescens Wils. ; 



Weissia vittata Braithw., Br. M. FL, Vol. II., p. 95). 



(Tab. XXXIV. H.). 



Resembling U. crispa in habit. Leaves with an oblong (not 

 widely oval), less dilated base, which has a deep narrow furrow 

 on each side close to the margin, often longer on one side of the 



