Rev. W. A. Leighton on new British Lichens. 403 



somewhat the appearance of the thallus o( Lecidea citrinella, Ach., 

 or even of the undeveloped apothecia of a Lecanora ; but the mi- 

 croscope and dissection show such appearances to be mere resem- 

 blances. 



Thelocarpon Laureri was first discovered by Flotow, in 1824, 

 in marshy places in the county of Glatz, Germany; and his 

 specimens appear to have lain in his herbarium undetermined 

 until 1846, when M. Laurer again found the lichen on turf 

 fences at Greifswald, and then drew M. Flotow's attention to it. 

 Flotow then described it, under the name of Spharopsis, in the 

 'Botanische Zeitung,' 18 17, p. 65, with this character: — ■ 

 " Spharopsis, Fw. (Verrucarieae, Porineae). — Apothecium verruci- 

 formc, ostiolatum, e thallo formatum, includeus nucleum soli- 

 tarium gelatinosum achromaticum. Perithecium proprium uul- 

 lum. Asci basilares ventricoso-fusiformes; sporas minutas ovales 

 numerosissitiias hyalinas foventes. 



" Sp/ueropsis Laureri, Fw. — Sph. hypothallo inconspicuo, crusta 

 gran uioso- verrucosa, flavo-viridi; verrucis acolytis plus minus 

 coufertis, fcrtilibus ostiolo impresso nigricante. Habitat ad 

 aggercs turfosos (Greifswald, Laurer, 1846) et in ericetis hu- 

 midis (Grafschaft, Glatz, 1824). Fw. herb. 1824, n. 285." 



Soon after, however, discovering that the name Spharopsis 

 had been already appropriated to a genus of Fungi, Al. Flotow, 

 in his letters (in 1848) to various botanical correspondents, 

 changed it to Thelomphale. Dr. William Nylander, apparently 

 without knowing of Flotow's change of name, described an- 

 other closely allied species from Algeria ( T. albiduvi, Nyl.), in 

 1854, altermg the generic name to Thelocarpon, which he has 

 retained in all his subsequent works. Korber, in the 4th part 

 of his ' Parerga Lichenologica,' published in 1863, relates the 

 circumstances of Flotow's early change of the name to Thelom- 

 phale, wliich he himself adopts. Nevertheless Nylander's name 

 Thelocarpon has priority of publication, and must, of course, be 

 adopted. 



Only three species of the genus are known : T. Laureri, Fw., 

 in Germany and England ; T. albidum, Nyl., with white thallus 

 and uniseptate sporidia, in Algeria ; and T. coccophorum, Mntg., 

 in Chili (apparently a doubtful species). 



Dr. Korber has compared our plant with his authentic speci- 

 men, and finds them identical. Dr. F. Arnold, of Eichstatt, in- 

 forms me that the German habitat is now destroyed. 



Plate IX. fig. 1 . Plant, magnified 20 times. 



fig. 2. Vertical section of apothecium. 



fig. 3. Asci and paraphyses in stellate form. 

 , fig. 4. Asctis and paraphyses. 



fig. 5. Sporidia, magnified 1200 times linear. 



26* 



