Diphyscium.] MUSCI-ACROCARPI-PERISTOMI. 13 



stand in rows from the centre to the circumference, so that when any 

 part of the lid is obliquely placed, with respect to the eye, the partitions 

 of the cells, in perspective, represent dark lines resembling radii; and 

 this appearance is so constant when the lower or concave side of the lid 

 is uppermost, in every part but that which may happen to be turned at 

 right-angles to the line of sight, that it is no wonder that Hedwig and 

 others believed in a fissile lid. The top of the columella always adheres 

 to the lid, and it is not easy to remove it. I made several longitudinal 

 sections in order to ascertain the texture of the lid, and always found 

 it to consist of the spongy body lining the concavity, and, on its removal, 

 an arch of pyramidal cells extending quite through the lid, without in- 

 terruption, thus proving the non-existence of a peristome. — These sec- 

 tions were allowed to dry under the microscope, and in an instant the 

 spongy portion of the columella shrunk up and disappeared, the diameter 

 of the lid became very much less : the concave side became plane, and 

 the upper or convex one was increased in convexity ; the thickness not 

 visibly altered, except so far as the spongy lining was in question. On 

 the application of water the original shape was restored. I may add 

 that when the Schistostega is in its infancy, it resembles a conferva with 

 globular articulations :— in this state it constitutes the " shining moss" 

 or " golden-green light,''' described by Mr. Bowman in the Mag. of Nat. 

 Hist. (v. 3. p. 462.). Of this fact I am well assured, having carefully 

 examined young half-developed plants possessing confervoid branches, 

 connected with the base of the stem." 



Subsect. III. Lid deciduous. Mouth of the capsule furnished 

 with a peristoma. Peristomi. 1 



Div. I. Peristome single. Aploperistomi.'- 

 8. Diphyscium. Mohr. Diphyscium. 

 Seta terminal. Capsule gibbous. Peristome single, forming a 

 plicate membranous truncated cone. Cali/pha mitriform. (Muse. 

 Brit. t. 1.). — Name, 2< ? , twice, or two-fold, and $-j«xr h a bladder, 

 from the double membrane of which the capsule is composed. 

 To mr this appears to be with great justice separated from 

 Buxbaumia by Mohr: and differing as it does in its foliage, as 

 well as peristome, from that Genus, I cannot but be surprised 

 thai Schwaegrichen, in his Sj>. Muse. Frondowrum, should 



have united them. 



1. D. folidsum, M ohr, (leafy Dipfyscivm), Mohr, <>l>s. Hot. 

 p. 34. Hook, in II. Loud. X. S. cum I< . thrum. Muse. Scot. 

 r. 1. //. 6. — Buxbaumia foliosa, Linn. Syst. Veget, p. 945. 

 11. lint. p. I I is. /•;. Hot. t. 329. Dill. Muse. /. 82./ 13. 



\\ ods, oo banks and wall-tops, in alpine situations. Fr. Summer. — 

 A minute plant, densely tufted. Stems none. Leave* small, ligulate 



rue 



ami entire, dark-green, opaque, furnished with a strong nerve. Ft 

 iijfra/inu large in proportion to the size of the plant," enveloped by the 

 perichsetial leaves, which arc lanceolato-oblong, membranaceous, acu- 

 minated, jagged at the extremity, having a strong, rigid, brown, excuxrent 

 nerve. Captule nearly sessile, ovate, oblique, gibbous. Calyptra mitri- 

 form. /.</ conical, acuminata cL 



///</, fend rftftm. tin* month. 

 ■ ecr>.»*i, tingle, combined with the word pnrUtomu. 



