27S F. O. BOWEK, 



The Germination a7id Embryogeny of Gnetum Gnemcyn. 

 By F. O. Bower, M.A., Lecturer in Botany at the 

 Normal School of Science, South Kensington. (With 

 Plate XXV.) 



Historical. 



Though the structure of the ripe seed in the genus 

 Gnetum is well known, and has often been described/ our 

 knowledge of the development of the embryo-sac, with its 

 contents, and of the embryo, is still very incomplete. Stras- 

 burger (' Ang. und Gymnosp.,' p. 116) has succeeded in 

 tracing that of the ovule with its several embryo-sac mother- 

 cells, and the first stages of development of the embryo-sac 

 in Gnetum Gnemon. But here our information stops short, 

 the further growth of the embryo-sac and of its contents not 

 having been follovved with accuracy. In the mature seed 

 the embryo-sac is found, as in other Gyranosperms, filled 

 with endosperm ; towards the apex of this is usually formed 

 a cavity, which in some species is filled with a coiled 

 mass of tubular structures ; this mass was described by 

 Blume (1. c.) and by Griffith (1. c.) as a funiculus (suspensor 

 in present terminology). In some species (G^. scandens, by 

 Griffith, and G, latifolium, by Blume) an embryo has already 

 been observed borne on the end of the coiled suspensors ; it 

 has two small cotyledons, and the figures given by these 

 authors correspond generally with certain stages of develop- 

 ment to be described^ below (cf. fig. 10). Further, in the 

 description of the characters of the genus Gnetum, it is 

 stated by Parlatore (* Prodromus de Candolle,' xvi, pt. ii, 

 p. 349), and by Tulasne (Martins' ' Flora Bras :' vol. iv, 

 pt. ii, p. 399), that the embryo is embedded in endosperm, 



' Blume, • Ann. Sci. Nat.,' 1834 ; and 'Rumphia,' Bd. iv, taf. 176, &c. ; 

 Roxburgh, ' Flora Indica,' vol. iii, p. 519; Griffith, 'Trans. Linn. Soc.,' 

 vol. xxii, p. 299 ; Hooker, • Trans. Linn. Soc,,' vol. xxiv, p. 39 ; Stras- 

 burger, ' Coniferen and Gnetaceen,' pp. 101, 236 ; Beccari, ' Nuovo 

 Giornale Botanico Italiano,' vol. ix, p. 91 ; Strasburger, ' Angiospermen 

 und Gymnospermen,' p. 100, 



