20 GYMNOSTOMI. [ Gymnostomum. 



Dieranum hyperboreum. Brid. Meth. p. 67. (Arnottj. 

 HAB. Wet dripping rocks, not uncommon. 



The difficulty of distinguishing the present from the preced- 

 ing species, it must be acknowledged, is in many cases very 

 great ; and we are ready to confess that in the first edition of 

 this work we ourselves have confounded them. Schwaegrichen's 

 figure of the G. rupestre is, indeed, very satisfactory ; and in 

 Drummond's Musci Scotici are published, as above quoted, 

 what we consider to be the true G. rupestre, and G. curviros- 

 trum. The former is of a much deeper green ; the leaves are 

 considerably longer, more linear, flaccid, flexuose or twisted, 

 both in a dry and moist state ; the nerve is thick ; the capsule 

 narrower, of a pale yellow brown, and the lid is less suddenly 

 rostrate and less oblique. Still we must allow that we have 

 seen intermediate states that have made us hesitate upon the 

 propriety of separating them ; and if the figures of Nees and 

 Hornschuch, referred to in the synonyms of the two species, be 

 carefully compared, a series will be found that appear to unite 

 the two extremes of one and the same species. 



We are not sure even whether future observations on the 

 noble Gymnostomum Hornschuchianum (erroneously figured as 

 a Hedwigia in Hook. Muse. Exot. v. 2. p. 103.) of Nees and 

 Hornschuch, Bryol. Germ. t. 11. f. 26. will not prove it to be a 

 very luxuriant state of G. rupestre. In all the essential charac- 

 ters it certainly agrees. 



* * Stems short, scarcely branched. 



6. G. Griffithianum ; leaves obovato-rotundate strongly reticu- 

 lated, their nerve disappearing below the summit, fruitstalk 

 thick succulent, lid hemispherical. (TAB. VII.) 



Gymnostomum Griffithianum. Smith, Fl Brit. p. 1162. Engl Bot. 

 t. 1938. Hook. Fl. Scot. ed. 2. ined. Drummond, Muse. Scot. v. 1. n. 9. 

 OEdipodium Griffithianum. Schwaegr. Suppl. v. 1. t. 105. 

 Bryum Griffithianum. Dicks. Crypt. Fasc. 4. t. 10. / 10. 

 Splachnum Froelichianum. With, and Hull, (according to Smith J. 

 HAB. In the crevices of rocks upon elevated mountains in 



England, Wales, and Scotland. 



This is a very rare and a very remarkable plant, with a good 

 deal of the habit of a Splachnum, but with a fruitstalk very thick, 



