82 The Irish Naturalist. 



Metzgeria conjugata of which a small portion is shown magnified 

 in Plate 3, fig. i, bearing copious adventitious shoots. In fig. 

 2, secondary branching of an adventitious shoot is shown. 

 The normal branches of the plant proceed from the pseudo- 

 nerve. 



Through the genera Btasia and Pellia^^ have the transition 

 to the foliose group, which is well shown in Pellia calyci^ia 

 and the variable Riccardia multifida. These plants are found 

 growing in large patches in damp places, increasing year after 

 3^ear by innovations, or young growths. Often a patch is 

 found crisped and apparently dead in dry weather, but on close 

 examination a few green shoots will be observed nourished by 

 the detritus of the mother-plant ; these shoots are sufficient to 

 reproduce the species. 



Amongst the foliose group, in the genera Ka?itia and 

 Ccphalozia we have examples of the gemmae borne on the apex 

 of attenuated branches. In Cephalozia Fjnncisci and C. denu- 

 data, they are copious and remarkable, of a bright yellow colour 

 when mature ; in Kantia they form bright pellucid clusters of 

 a brilliant green or yellow colour at the apex of the branches, 

 leaves, &c. Dr. Spruce very aptly calls these bodies 

 "propagula." Of leaf-gemmae we have familiar instances in 

 Jitngermania incisa and J. veiitricosa and species in the genus 

 Scapania. In Radiila compla7iata and Madotheca platyphylla 

 we have examples of simple cells becoming detached as gemmae 

 from the margin of the leaves. Dr. Spruce records' an instance 

 of shoots or branchlets growing from the leaves oi Jurigermaiiia 

 juniperina, which he collected at Cromaglown, Killarne}^ when 

 on a visit to Dr. Taylor. This interesting notice is illustrated 

 by a woodcut showing two leaves with a branchlet on 

 each. 



In his exhaustive work on the Hepaticae of the Amazon and 

 Andes, Dr. Spruce notices the disintegration of the marginal 

 cells in the genus Plagiochila ; the loosened cells hang awhile 

 in little masses, then fall away, and are dispersed, some to 

 renew their growth as distinct individuals. Sir William 

 Hooker in his grand work on the British j2cngcrma7ii(B mentions 

 a few species, now in the genus Lejeimea, on which he found 

 gemmae, and these appeared to be produced on their stems. 



^ Phytologist, vol, ii., 1845, p. 85. 



