GRIMMIACE^E.] 65 [Orthotrichum. 



cleft at apex, like those of Z. conoideus, articulations numerous, minutely 

 vermiculate, cilia 8, partly adhering to the teeth. Male plants in separate 

 tufts, more slender, infl. terminal, stoutly gemmiform, bracts ovate, 

 acuminate, the nerve thin and vanishing, antheridia and paraphyses 

 numerous. 



HAD. Calcareous rocks and walls rare. Fr. 5 6. 



Middlehouse. near Malham Tarn (Newell 1856)! ! and c. fr. (Whitehcad 1879). Old 

 limestone walls, Heselton gill, Litton dale c. fr. (Nowcll 1866) ! Ingleboro, in the 

 ascent from Clapham (West 1876) ! ! Connemara, Ireland (Wilson). 



This species has quite a different aspect from the other European forms> 

 resembling most the Mexican Z. campylophyllns C. MUELL. The fruit is 

 rare with us, but has been found in good condition in the Tyrol. 



7. ORTHOTRICHUM HEDW. 



Muse, frond, ii, 96 (1788). 



Growing in round cushions on trees, rocks or walls. Leaves 

 lanceolate, generally recurved at margin, not dilated at base, imbricated 

 or twisted when dry, minutely papillose, cells punctiform and chloro. 

 phyllose above, hyaline and elongate below. Capsule on a short 

 pedicel, as long or longer than the ochreate vaginula, immersed or 

 exserted above the leaves, 8 16 striate, the striae alternating with the 

 teeth, prominent or forming ribs when dry, very rarely none. Teeth of 

 peristome 32, geminate or bigeminate, formed of one series of quadrate 

 cells; endostome of 8 or 16 cilia, filiform, articulated, alternate with 

 the teeth, often rudimentary or abortive. Calyptra mitraeform, lobed 

 at base, conico-campanulate, plicate, naked or covered with straight 

 filiform ramenta. Der. o/a0os straight, fyn hair. 



About 120 species of Orthotrichum have been described, but judging by a 

 study of our native species, it is to be feared that many of these must sink 

 into synonyms. The great difficulty in dealing with the genus is the great 

 uniformity in the habit of the species, and, with a few exceptions, the little 

 variation to be met with in the form and structure of the leaves. These are 

 more or less imbricated when dry, but when wetted, quickly become recurved 

 from the base and then gradually erecto-patent, in shape oblongo-lanceolate, 

 or sublinear, the point obtuse, acute or acuminate, very rarely piliferous, the 

 margin usually revolute, the upper cells incrassate, usually bearing coarse or 

 fine, cleft or conical papillae. The vaginula is smooth or hairy and is 

 crowned by a little membranous tube enclosing the pedicel, named the 

 ochrea or vaginal tube, this pedicel is usually very short, so that the fruit is 



