384 LESKEACE/E. 



shorter and wider at base, sparsely but sharply papillose at back. 

 Seta long, capsule arcuate. Dioicous. 



Hab. Wet places on mountains, very rare ; Highlands of Scotland. Fruit 

 extremely rare, not found in Britain. 



In the habit, the falcate branch-leaves, and other points this species is quite 

 distinct from any other of the genus, and more closely resembles Hypnum commutalum. 

 It is a more slender plant with shorter branches than the usual forms of that moss, 

 and may at once be distinguished under the microscope by the papillose leaves with 

 the cells, especially towards the base, much looser, being both shorter and wider. 

 In areolation indeed, it comes nearer Amblystegiumfilicinum, but the stem leaves are 

 wider and plicate. The leaves when dry, moreover, are somewhat crisped, and are 

 dull, not glossy as in H. commutation. 



There has been much difference of opinion as to the true systematic position of 

 this plant, several authors placing it in Hypnum near H. commutalum ; the papillose 

 leaves form the chief argument for placing it in the present genus, and the view thus 

 taken is supported somewhat by the fact that in T. Blandovii the form of the branch 

 leaves, the areolation and the character of the papilla? all show a distinctly intermediate 

 condition between the typical characters of Thuidium and those of the present plant. 



4. Thuidium tamariscinum B. & S. (Hypnum tamariscinum 

 Hedw.) (Tab. LI. E.). 



Stems elongated, 3-8 inches long or more, arched, often- 

 interrupted, the apex being produced without branches for some 

 distance, and often rooting, then again branching ; this may be 

 repeated several times. Plants in large, intricate mats, bright 

 vivid green. Branches complanate, tripinnate , the lower or 

 median ones longest, so that the outline of the frondiform stem is 

 deltoid or lanceolate ; secondary and tertiary branches short, very 

 slender, attenuated. Stems and branches clothed with numerous, 

 short, multifid paraphyllia. Stem leaves widely cordate, from a 

 broad base, rapidly contracted to a narrow acumen of varying 

 length, plicate ; erecto-patent or somewhat recurved, when dry 

 appressed, not crowded ; margins revolute to the base of the 

 acumen, denticulate above ; nerve very strong, reaching nearly to 

 apex; cells short, wide, incrassate, rounded-quadrate or irregular, 

 in acumen elongated, elliptical ; towards base longer, sub- 

 rectangular ; at basal angles rectangular, slightly larger. Papillae 

 acute, dense. Leaves of the primary branches somewhat inter- 

 mediate between those of the stem and of the secondary and 

 tertiary branches ; of these latter very small, narrow, ovate- 

 lanceolate, shortly pointed, concave ; cells oval-rounded, densely 

 papillose, the apical cell simply acute. Perichaetial bracts long, 

 gradually or rapidly contracted to a long, flexuose, thong-shaped 

 acumen, much longer than the limb ; the margins, especially of 

 the inner ones, densely fringed with long, filiform, articulate 

 cilia; nerve strong, reaching to base of acumen. Seta stout, 



