Rev. W. A. Leighton on tho British Umbilicariae. 275 



which the apothecia of the gcmis arc so conspicuous and re- 

 markable. 



So far as my opportunities of research extend, the first writer 

 who mentions these plants is Tournefort, in his Institutiones 

 Uei Herbaria;, 1710, who describes, in the concise manner usual 

 with earlier writers when treating of Lichens, two species, U.pus- 

 fuhita and f/ri.sca. Vaillant, following his great master, in his 

 Botanicon I'arisiense, 17.'27, describes and figures the same two 

 species, with that characteristic accuracy and fidelity for which 

 his plates are so valuable. Micheli, in his Nova Genera Plan- 

 tarum, 1729, makes U. pustulafa the sole type and constituent 

 of his IHth Ordo of Lichens, in which the seeds are disj)Osed 

 " in comosa arbuscula " over the whole surface of the plant. 

 These seeds, which arc now ascertained to be pulverulent ex- 

 crescences of the thallus, he figures with much accuracy, and 

 also the apothecia, of which however he takes no notice in his 

 description, ])ossibly supposing them to be only the incipients of 

 the fructification which would be ultimately developed into the 

 "comosa ai'buscula.^' His tab. 47 represents characteristically 

 a veiy large specimen in that torn or deeply divided state fre- 

 quently observable when the plants attain considerable magni- 

 tude, and apparently resulting from this excess of growth. He 

 complains that A'aillant^s figure is taken from too small a spe- 

 cimen, but identifies it with his own, having received an authentic 

 specimen from Vaillant himself. Dillenius, in his Historia Mus- 

 corum, 1741, describes at length and figures U. pruhoscidea, 

 Turn, and Borr., _</mw, Ach., erosa, HofFm., nrctica, Ach., puli/- 

 p/u/llu, T. and B., ppllifa, Ach., and jmstutata, Ach. 



Linuffius, in Species Plantarum, 1763, under his section 

 Lichenes Umbilicati includes six s])ccies, vdleus, jiustidatus, pro- 

 hoacideus, deus/us-, pulijphi/llus, and pobjrrhizos. The same ar- 

 rangement is followed by PoUich (Klor. Palat. 1777), Lightfoot 

 (Fl. Scot. 1777), Weber (Spicil. Gotting. 1778), Hudson (Fl. 

 Angl. 1778), Hagcn (Tent. Pruss. 178.2), Humboldt (Fl. Frib. 

 1793), lletz (Fl.Scand.l79.^), Withering (Arrang. 1795), Afze- 

 lius (Act. Upsal. 1788), Westring (Act. Sc. Stockh. 1793), and 

 Acharius (Act. Sc. Stockh. 179t), varying indeed in the number 

 of species described according to the circumstances of then- 

 respective localities. Hoffmann, in his Plantre Lichenosa> in 

 1788 (according to the date on his tab. 2) first uses the generic 

 name Umhiiicaria. He figures with inimitable beauty and accu- 

 racy eleven sjiecies. This name Umhiiicaria was innnediately 

 adoj)ted by Baunigarten (Flor. Lips. 1790), Schrader (Spicil. 

 1794), and Acharius (Prodr. 1798). In this latter work it 

 should be mentioned that Acharius refers mnrinus to the geinis 

 Endocnrpon. The generic name Umbilicaria is vei'y aptlv taken 



18* 



