Page:The Botany of the Antarctic Voyage.djvu/571

Falklands, etc.] 6. Lecanora Babingtoni, Hook. til. et Tayl.; thallo crustaceo adnato orbiculari subsquamuloso areolato areolis radiantibus albido-glaucesceute demum virescente, squaniulis diffractis ambitu sub-continuis crenulatis, apotheciis adnatis margine thallode tenuissinio evanescente, disco atro primitus tumido margine subelevato demum plauiore irnmarginato. Lecidea atro-alba, nobis in Loud. Journ. Bot. vol. iii. p. 636 {quoad exempt. Ins. CocEurn). (Tab. CXCVIII. Fig. II.)

Hab. Cockbum Island, Graham's Land; on volcanic rocks.

Tliallus inconspicuus -i— 1 unc. diametro, margine definito crenulato, totus in areolas minimas (non nisi ope lentis conspicnas) diffractus ; areolis angulatis, albidis, sasse adnatis, centralibus fertilibus, reliquis radiantibus, extimis subfoliaceis lobatis crenulatisve. Apothecia punctiformia, interiora majora subconfluentia.

Although the specimens of this plant brought from Cockburn Island are very perfect and well developed, they belong to so difficult a group of Lichens as to have baffled the Rev. Mess. Babington, Berkeley, and ourselves, in our attempts to reduce it to any known species. Though closely resembling a Lecidea in habit, and, indeed, in characters too, it is certainly not of that genus, for though, as Mr. Berkeley remarks, the apothecia of Lecid. rivulosa and confluent are sometimes obscurely margined (as in this species), yet, Mr. Babington observes, that the thallus here is radiating, which is not the case with the areolate Lecidea, nor has it the carbonaceous margin to the apothecium and substratum of that genus.

Of the tribe in which it should be placed (as a Lecanord) there is some doubt : Mr. Berkeley regards it as belonging to the section "glaucescentes" of Placodium, Fries, and allied to L. coarctata, in which the thallodal border of the apothecium is evanescent. Mr. Babmgton, on the other hand, remarks, that the thallodal border and that of the disc itself place it in Psora, Fries, and that it will rank amongst the section "glaucescentes" near L. melanaspis, of which it may possibly be a variety, or a depauperated and crustaceous form. The figure represents the plant as freshly gathered, before drying ; it has since assumed a more obscure, somewhat leaden colour, and the oldest portions of the thallus break up into a greenish mass, which is not given in our plate.

Plate CXCVIII. Fig. II. — 1, plant of the natural size ; 2, portion of ditto ; 3, central part of thallus and apothecia; 4 and 5, lateral views of areola and apothecia; 6, vertical slice of two apothecia; 7, portion of lamina proligera : — highly magnified.

7. Lecanora. getida, Ach.; Lic/i. Univ. p. 428. Engl. Bot. t. 699. Urceolaria macropthalma, nobis in Lond. Journ. Bot. vol. iii. p. 640.

Var. 0. vitellina, thallo vitellino.

Hab. Kerguelen's Land ; both varieties very common.

The variety 0. is probably dependent on the thallus having changed colour-. What was described as Urceolaria macropthalma is a state noticed by Fries (Lich. Europ. p. 104). C.Babington.

8. Lecanora murorum, Ach.; Lich. Univ. p. 433. Engl. Bot. t. 2157. V&r.farcta ; apotheciis substantia granulata fere clausis.

Hab. Hermite Island, Cape Horn, the Falkland Islands, and Cockburn Island, Graham's Land; on maritime rocks. Var. 0. Kerguelen's Land ; on rocks near the sea.

9. Lecanora miniata, Ach.; Lich. Univ. p. 434. Hoffm. Plant. Lich. t. 60. f. 1.

Hab. Falkland Islands, and Cockburn Island, Graham's Land; very abundantly on rocks near the sea.

This plant forms the most curious feature in the botany of Cockbum Island, a desolate spot of land on the extreme limit of southern vegetation; for there it abounds so as to stain the rocks, and render the colour thus