506 INTRODUCTION TO CRYPTOGAMIC BOTANY. 



dium and Gatharomnion have been added by Hooker and 

 Wilson, in the Flora of New Zealand. Hypopterygium has 

 the peristome of Hypnum; LopkUum, of LesJcea; while 

 Gatharomnion has a simple internal row of teeth. The 

 species are natives either of the Southern Islands and Chiloe, 

 or of warm countries. Gyathoplioriiin 'pennatwm is one of 

 the most beautiful of mosses, and is remarkable for its short 

 curved peduncles inserted in a tumid vaginula. The fruit 

 (Fig. 109) is produced in the axils of the lateral leaves, which 

 are large and of a dark green. 



13. Racopilacei, Hook. & Wilson. 



Stems creeping, subpinnate ; leaves mostly dimorphous ; 

 intermediate leaves smaller, seated on the upper side, minutely 

 areolate ; calyptra mitriform, pilose at the base. 



567. Allied to the last, but the amphigastra are differently 

 placed, and the calyptra is remarkable for its hairy base and 

 margin. The habit, moreover, is very different, approaching 

 that of Hypnum, which the species resemble in the curved 

 unequal sporangia. Like the last two tribes, they belong 

 either to the Southern Islands or to hot climates, as the 

 Philippine Islands. 



568. Mosses are no less variable than other Cryptogams, and 

 are therefore frequently very difficult to distinguish. Not 

 only will the same species exhibit great diversity in the size, 

 mode of branching, form and nervation of the leaves, but 

 the characters of even the peristome itself are not con- 

 stant, as I have already pointed out ; nor is it always easy to 

 assert whether the calyptra is mitriform or dimidiate, as this 

 may depend upon the form assumed by the sporangium after the 

 peduncle has raised the calyptra up. If, indeed, it is taken 

 into consideration in what very different climates and situations 

 these Cryptogams occasionally grow, we shall be prepared for 

 quite as much change as actually appears, and shall be very 

 cautious in the absence of marked characters of separating 

 species. The greatest cause, however, of perplexity in the 

 study of mosses arises from the loose manner in which par- 

 ticular species are assigned to genera, and the vague notions 

 which exist as to affinity. In the present state of our knowledge 



