104 DICRANACEiE. 



B. EU-DICRANUM. 



6. Dicranum undulatum Ehrh. (Tab. XVII. H.). 



Stems robust, tall, 3-10 in. high, decumbent at base, in loose, 

 wide tufts, densely coated with tomentum, bright shining yellowish 

 green. Leaves very long, spreading or squarrose, slightly turned 

 to one side at times, the upper erect or faintly secund, forming a 

 cuspidate tuft, not much altered when dry, from a long broadly 

 lanceolate base gradually narrowed to an elongate, flexuose, but 

 not very narrow, sharp acumen, margin recurved below for about 

 \-\ the length of the leaf, thence upward strongly spinosely 

 serrate to apex ; nerve narrow, vanishing in the apex, with two 

 serrated ridges at back above ; cells at angles wide, orange brown, 

 a patch of interior ones often hyaline, forming auricles which 

 together cover about half the width of the leaf, the median cells 

 between these and the nerve very narrow ; all the rest of the cells 

 almost uniform throughout the leaf, linear-fusiform or narrowly 

 and longly elliptical, the walls incrassate with rather few but very 

 distinct pores, the marginal cells somewhat shorter. Perichaetial 

 bracts long, broad, convolute, forming a cylindrical sheath ; setae 

 aggregated, 2-5, rarely single, pale red, long ; capsule rather 

 small and short, gibbous, curved, striate and pale brown when 

 ripe and empty. 



Hab. Woods and heaths. Very rare. Wolford, Warwickshire (Bagnall, 

 18&7) ; Perthshire (Meldrum). Fr. late summer. 



D. undulatum is one of the finest of our species, and it is remarkable that its 

 presence should have been so long undetected in this country, being as it is a widely- 

 distributed plant on the Continent and in N. America. It recalls the most robust 

 forms of D. scoparium, but its leaves are as long as and longer than those of D. 

 ma/us, though straighter, and so strongly undulated and rugose as to give the dry 

 plant a distinct silky sheen. The recurved margin at base and the very coarse 

 serratures above are quite enough, by themselves, to separate the plant from all forms 

 of D. Boiijeani, while the undulated leaves mark it off at once as distinct from D. 

 scoparium and D. majus. The fruit has not been found in this country. 



7. Dicranum spurium Hedw. (Tab. XVII. G.). 



Green or yellowish green, robust, 2-4 inches high, less densely 

 tufted than the next species, less tomentose. Leaves somewhat 

 larger at the summit of the stem, when dry incurved and cirrate- 

 crisped in the upper half, strongly rugose, broadly oval, wider 

 above than at the line of insertion, quickly contracted to a more 

 acute acumen, which is usually twisted ; margin more or less 

 serrate above ; cells at base similar to D. Bergeri, above also 



