353 



A NEW BEITISH HEPATIC. 



By W. H. Peakson. 



(Plate 292.) 



Lejeunea (Cololejeunea) Rossettiana Massal. — ^^Dioica? 

 intricato-caespitosa, minuta, flavo-viridis, habitu et magnitudine 

 Lejeiineam calcaream omnino referens, examphigastriata ; caide 

 subdichotomo, vel subpinnatim diviso, subtus plus minus radicel- 

 loso ; foliis dense imbricatis, convexulis, ovatis, apice magis 

 minusve longe attenuato-acuminatis (rarias solum acutis), acumine 

 plerumque infiexo, margine facieque externa eximie echinatis ; 

 lohiilo folio minore subtriplo, ad plicam tumido, margine sub- 

 rotundato, inaequaliter valideque spinuloso, tota superficie (externa) 

 ad foliorum instar echinata (appendice styliformi inter lobulos et 

 caulem nulla) ; cellulis fol. lobulorumque leptodermibus ; poly- 

 gonalibus in papillam conicam sat alte promineutibus ; perichatiis 

 subsessilibus,/oZus involucralibus conduplicato-bilobis, margine den- 

 tatis, superficie echinatis, lobo dorsali acuto, ventrali vulgo minore 

 et obtuso ; colesula ad speciem stipitata, pyriformi, apice pentagona, 

 ore mucronata, tota face mucronata ; infl. (^ ?." Massalongo in 

 Nuovo Giorn. Bot. Ital. vol. xxi. p. 487, Lugiio 1889, emend. 



Dioicous, minute, growing in closely-matted tufts of a yellowish 

 green colour, often growing in company with Lejeunea calcarea, 

 which it resembles in size and habit. Stems subdichotomous or 

 subpinnate ; rootlets of a pale colour, proceeding from the base of 

 each leaf, or obsolete. Leaves imbricate, patent at an angle of 

 50-60°, somewhat convex, ovate, with their apices more or less 

 attenuate-acuminate (rarely only acute), usually incurved, margin 

 denticulate, exterior surface echinate ; lobule from half to a third 

 smaller than the leaf, tumid at the keel, then nearly flat, margin 

 subrotund, not incurved, unequally dentate-spinulose, exterior 

 surface echinate Iflie leaves, cells very minute, 4-5 and 6-angled, 

 walls distinct, without trigones, papillte conical, one to each cell ; 

 styliform appendage to the base of the leaf wanting. Folioles none. 

 Female flowers on short branches, subtended by an innovation ; 

 bracts similar to the leaves, only larger; lobule more finely 

 dentate-spinulose ; bracteole wanting. Perianth projecting more 

 than half beyond the bracts, oval to pyriform, muricate, upper 

 portion obtusely 5-angled. Male flowers unknown. 



Measurements. —Stems about 5 mm. long, -1 mm. diam. ; 

 leaves -45 x -25, lobule -225 x -15 mm., -45 x -275, lobule -225 x 

 •15 mm.; cells -0125 mm. ; papillae -0125 long x -01 mm. at the 

 base; bract -5 x -25, lobule '25 x -15 mm.; perianth -6 x -45 

 •55 X '4 mm. 



Hab. — Growing on limestone rocks, amongst mosses, and often 

 intermingled with L. calcarea. England : Limestone Cave, Gor- 

 dale, 10th July, 1857; 3rd July, 1872, Dr. Carrington. Miller's 

 Dale, Jan. 1882; Winnats, March, 1882; Ravensdale, May, 1884; 

 Derbyshire, Mr. G. A. Holt. Ireland: Near Dublin, 1830, Dr. 

 Taylor. Mucross Demesne, Killarney, May, 1861, Dr. Carrington. 



JouENAL OF Botany. — Yol. 27. [Dec. 1889.] 2 a 



