HIPETS'ING OF SEED IN GNETUM GXEMON AND 

 GNETUM AERICAXUM . 



By Mahy G. Tiioday, 



Litle Fellow of .Xeicnliani Collefjc, Caiiihiuhjc, and latr. 

 Hon. Researclt Fellow of Manchester V nivcrsifij. 



Wi'flt Tiro Tevt Figures. 

 Read Jnljj IT, 1920. 



This paper is a continuation of previous "work* on various 

 species of Gnetum, describing- the series of changes in tlie 

 seed coats during the development of the seed. 



The young- seed has tliree coverings, all of wiiich are 

 free, the innermost projecting- upwards as the niicropylar tube. 

 In tlie largest seeds of Gnetum yet described — G. ynenton 

 by Miss Berridge and G . africanuni by myself — the tip of 

 the niicropylar tube enlarges and forms a stopper, which 

 becomes adherent to the middle covering- and which has its 

 lumen closed so that no foreign substance can enter either 

 the niicropylar tube or the chink betv^■eell it and the middle 

 covering- after ])ollinatioii. 



In the seeds of G. fjnonon now described, three centi- 

 metres long-, remarkable later changes occur which would 

 make the morphology of the mature seed impossible to under- 

 stand were its earlier stag-es not known — for exami)le, if it 

 were only known as a mature fossilised seed. 



Young Ovuli-:. 



Fig. 1 is a diagrammatic view of a young ovule of 

 (7. fjneinon, ■] mm. long, in whicli (dosure of the inicroi)yle 



Fi^. 1. — L'pper portion of youiifj; seed (3 mm. lon^) of ^'. (incin 

 * Tl.oaay, 191] . 



