AMBLYSTEGIUM. 447 



very slender, prostrate, small-leaved forms, some of which are so slender as to bear a 

 close resemblance to A. serpens. From Hypnum commutatum, A. filicinum differs 

 in the narrower, more rigid and scariose leaves, not crisped when dry, nor deeply 

 plicate, never circinate nor perhaps ever so strongly falcate as to form a half circle, 

 and especially in the very different, wide, sub-hexagonal areolation. The differences 

 between the present plant and A. irriguum have been dealt with under that plant, but 

 some remarks are necessary with regard to the var. Vallisclausm. Much has been 

 written and very different opinions are held with regard to the true place of this 

 plant, some authors maintaining it as a species, others referring it to one or other of 

 the two species in question ; it appears clear that both A. irriguum and A. filicinum 

 give rise to analogous forms, which are hardly distinguishable, but may probably be 

 always separated by the basal areolation and form of the leaves ; the latter in A. 

 irriguum var. spinifolium being narrower, ovate-lanceolate only on the stems, 

 lanceolate on the branches ; while the stem-leaves of A. filicinum are cordate-ovate 

 at base, and the branch-leaves ovate or oblong-lanceolate, with the auricles more or 

 less clearly defined and inflated, which is not the case in A. irriguum ; paraphyllia 

 are frequently though not always found in the present variety, but are probably 

 always entirely absent in the forms of A. irriguum. Hypnum falcatum var. 

 irrigatum is a form similarly related to H. falcatum ; it is readily known by the 

 longer, narrower areolation. 



The already complicated nomenclature of the present variety has been rendered 

 still more involved by the transference of the name Vallisclausm by Husnot to the 

 analogous forms of A. irriguum (including var. spinifolium Schp. ), that author 

 holding that Bridel's name referred to a form of the latter species, not to A. 

 filicinum. In the absence of clear proof I have thought it best to retain the more 

 usual application of Bridel's name to the var. of the present species. 



All the British plants I have examined of these forms belong distinctly to A. 

 filicinum, and are therefore to be referred to its var. Vallisclausce ; nor do I know of 

 any British records of the form belonging to A. irriguum. 



The basal auricles in H. filicinum are sometimes exceedingly distinct, but 

 occasionally are less marked and with rather incrassate walls ; the leaves are, how- 

 ever, almost always more deltoid at the base than in A. irriguum, and the angular 

 cells are probably always, even in the above cases, much more strongly marked ; the 

 inflorescence is also an important distinguishing character. The fruit is rare in the 

 present species. 



8- Amblystegium curvicaule Lindb. (as sub-spec.) Hypnum 

 curvicaule Juratz., Schp. Syn.) (Tab. LVI. E.). 



Stems creeping or ascending, hardly radiculose, divided, 1-2 

 inches long ; the divisions sub-simple or more or less regularly- 

 pinnate, flexuose ; branches slender, rather obtuse, or acute, 

 usually curved at the tips ; forming low tufts of a yellow-green 

 or golden colour, yellowish internally, rather soft. Leaves erecto- 

 patent, when dry erect, loosely imbricated, often sub-secund, at 

 apex of branches here and there falcate, cordate-triangular or 

 widely cordate-ovate, short, yi line in length, narrowed above, 

 then rapidly, almost suddenly acuminate in a short slender point , 

 decurrent at base, concave, sometimes slightly plicate, of rather 

 soft texture ; margin plane, minutely denticulate ; nerve strong, 

 reaching to the acumen and there becoming indistinct and vanish- 

 ing ; cells resembling those of A. filicinum, but narrower, 

 elliptic-hexagonal or elliptic-linear, usually 3-6 times as long as 

 broad, pellucid, the walls firm and somewhat incrassate ; laxer at 



