POLYTRICHACE^.J 36 



beautiful of known mosses ; here both the peristome and endostome are 

 broken up into a brush-like tuft of cilia, and there is no epiphragm. In 

 both these genera we recognise a certain affinity to Buxhaumia by the 

 depressed, ovate and somewhat irregular capsule, and again the scabrous 

 seta of Buxbanmia is represented in the Malayan Racelopus, a feature quite 

 exceptional in this family, where it is usually polished and wiry. Lindberg's 

 paper " Ohseyvationes de formis pnsertim euvopmis Polytrichoideamm," in Notis. ur 

 Sitllsk. pro Fn. et Fl. fenn. fdrh. ix, p. 91 (1867), is perhaps the most perfect 

 example of a botanical dissertation which has ever come before us. 



In this a very curious relation existing between the peristome and 

 epiphragm is pointed out and used to divide the genus Polytrichmn into two 

 sections Pterygodon and Leiodon, but as the parts are very minute and would 

 offer difficulties to students in their examination, we have preferred the older 

 divisions of C. Mueller. 



A part of this beautiful combination was first accurately made known 

 by our celebrated countryman Richard Spruce in his paper on " The Mosses 

 and Hepatica of the Pyrenees" in Trans. Bot. Soc. of Edinburgh, iii, 162 (1849) ; 

 and as these structures are so important, it may be of interest to quote the 

 descriptions of both authors. 



Spruce says, — " In Polytrichum alpinum the epiphragm is originally placed 

 at the base of the teeth, to which it is attached by means of processes equal 

 to them in number, and exactly covering their internal face. After the fall 

 - of the lid, these processes are gradually detached, and the epiphragm rises, 

 probably from the pressure of the full-grown spores beneath it, so as to allow 

 the latter to escape through the interstices of the peristome. When the 

 epiphragm is quite liberated, the processes curve inward upon its upper 

 surface, so as to be with difficulty seen, unless the light be properly regulated, 

 or the epiphragm be set up on its edge. The adhesion of the epiphragm to 

 the teeth is so great as to resist the action of the columella to draw it down 

 into the capsule, and often ultimately to cause the columella to rupture." 



Lindberg's description is as follows, — " In the Polytrichacea the teeth 

 are incurved and in transverse section triangular, especially at the base ; the 

 inner surface of the teeth is elevated in the middle into a longitudinal crest, 

 which is composed of the innermost cells of the basal membrane not reaching 

 the apex of the tooth. The apices of these cells in the subgenus Pterygodon 

 are not united to the teeth, but inflexed, free or irregularly connected with 

 each other, and form wings, compressed at the sides, and resembling stag's 

 horns. These wings are formed both from the basal membrane itself, and 

 the lower part of the crests of the teeth, and are somewhat coloured or 

 hyaline; they enclose chambers of the same number as the teeth, in the 

 mouth of the capsule, the fundus of which is formed by the basal membrane, 

 the walls by the teeth and their wings, and the roof by the epiphragm ; these 

 spaces are fenestrae for the exit of the spores, when the spore sac finally 

 bursts at apex. The species referred to Pterygodon are P. commune, juniperinum, 

 strictum and piliferum, and in these also the epiphragm is thin, flat and strictly 

 contained between the apices of the peristome, to which it closely adheres by 

 the margin. From its lower surface and within the margin, hang down 

 sacculi or nipple— like processes, closing the upper part of the interdental 

 spaces, almost to the middle of the teeth, and as many in number as the 



