1062 



THE FERN FAMILY. 



Fig. 1294. 



1. Tunbridge Hymenophyll. Hymenophyllum 



tunbridgense, Linn. (Fig. 1294.) 



(Eng. Bot, t. 162. Filmy Fern.) 



Rootstock very slender, creeping, and 

 much branched with numerous fronds, 

 forming broad, dense, almost mos3-like 

 patches. Fronds pinnate, seldom above 

 2 or 3 inches long, lanceolate in gene- 

 ral outline ; the stem very slender ; the 

 segments deeply divided into 3 to 8 or 

 more oblong linear lobes, which appear 

 minutely toothed when seen through a 

 lens. Involucres at the base of the seg- 

 ments or their lobes, on their inner edge, 

 ovate, about a line long, deeply divided 

 into 2 flattish lobes, often minutely 

 toothed round the edge. 



In moist, rocky, or shady situations, 

 dispersed over most of the warmer 

 mountain districts of the old world, es- 

 pecially in the southern hemisphere ; 

 more rare in America, extending from 

 the Canary Islands and north-western 

 Africa along western Europe to Belgium 

 and JSTorway, but not recorded from 

 eastern Europe or any part of the Rus- 

 sian dominions, nor from Ts orth America. 

 Generally distributed over the greater 

 part of Britain, but more frequent in 

 Scotland, northern and western England, 

 and Ireland, than in eastern England. 

 Fr, summer and autumn. A variety 

 with the valves of the involucre entire, 

 not toothed, is usually distinguished as a 

 species, under the name of H. unilaterale 

 orH.Wilsoni,Y\g. 1295 (Eng. Bot. Suppl. 

 t. 2686), but the other characters, said to 

 accompany this one, such as the narrower 

 involucres, the different direction of the 

 lobes of the fronds, etc., do not appear to 

 me to be so constant as they are supposed to be, and the teeth of the 

 valves, when present, are very variable. The entire-valved form is the 

 most common in Scotland and Ireland, but the two are often intermixed. 



Fig. 1295. 



