484 INTRODUCTION TO CRYPTOGAMIC BOTANY. 



peristome none ; calyptra conical, smooth, or hairy ; leaves 

 nerveless. 



534 The mosses of which this tribe is composed are distin- 

 guished by their nerveless leaves, the absence of the peristome, 

 and the lax, not compact, patches which are formed by the 

 shoots. In the European ' forms the stem is often very short, 

 but this is by no means the case uniformly. They occur in 

 alpine countries, but are not confined to cold regions. Species 

 are found in Brazil, Kumaon, St. Vincent's, and other tropical 

 stations ; and the southern hemisphere has one or two ex- 

 tending from the Cape to higher latitudes. Hedwigia Hum- 

 boldtii, for instance, occurs at the Cape and at Hermite Island ; 

 and the same species is abundant in Lord Auckland's and 

 Campbell Island. This is perhaps the finest of the tribe, and 

 was originally found on Quindiu, in New Grenada, by Hum- 

 boldt and Bonpland, so that the species has an immense 

 geographical range. This tribe might probably be united with 

 Hydrojwgonece. The characters, at least, are very similar. 

 They differ principally in their habitat. 



11. Grimmiei, Br. & Sc, Mont 



Sporangium equal, often sessile ; peristome single ; calyptra 

 mitriform ; leaves of a dark green, always terminated by a 

 white hair ; cells punctiform. 



535. The minute hexagono- punctiform cells of the upper 

 part of the leaves and the white projecting nerves distinguish 

 these mosses, which either form dense pulvinate tufts or wide- 

 spread masses. Racomitrium lanuginosum, for instance, 

 forms beds many yards in diameter on dry mountain sides, than 

 which nothing can be softer or more luxurious. Schistidium, 

 differs principally from Grlmmia in the immersed sporangia, 

 and the columella adherent to the lid. The peristome is ex- 

 tremely variable ; the teeth are often split as in Dicranwni, and 

 in one species they are altogether absent. Racomitrium 

 differs from Grimmia in the hypnoid habit, a distinction con- 

 firmed by the subulate papillose beak of the calyptra. It is 

 connected with Grimmia by Dryptodon, which has dichoto- 

 mous branches and simple fastigiate innovations ; while in 

 Racomitrium the branches are irregular, and the innovations 



