GERMIXATION AND EMBRYOGENY OF GNETUM GNEMON. 283 



after the protrusion of" the radicle the hypocotyledonary 

 stem increases rapidly in lengthy and, curving upwards, 

 gradually draws itself out from the cavity of the endosperm, 

 leaving the seed below ground. The organ swells as soon 

 us the hypocotyledonary stem is withdrawn from the endo- 

 sperm ; the space vacated by the stem is thus filled up, and 

 the feeder comes into immediate contact over its whole 

 surface with the endosperm. 



The hypocotyledonary stem, which is pink, gradually 

 becomes erect, and, elongating rapidly, attains a length of 

 about six inches. The cotyledons, which have hitherto re- 

 mained small (cf. fig. IT), now begin to expand and turn 

 green ; finally they assume the appearance of the ordi- 

 nary foliage leaves of Gnetum, being petiolate with a thick 

 midrib and reticulate venation. They sometimes exceed 

 three inches in length. The stout primary root grows to a 

 considerable length, and forms lateral roots at an early stage 

 (fig. 18). 



The plumule remains a simple papilla of tissue till the 

 cotyledons begin to expand ; it then forms two opposite 

 plumular leaves decussating with the cotyledons, and these 

 are followed by other pairs of leaves having a similar mutual 

 arrangement. Soon after the plumular leaves appear, an 

 axillary bud begins to be formed in the axil of each of the 

 cotyledons, and these form opposite pairs of leaves in planes 

 parallel to those of the plumule. Further, secondary axillary 

 buds appear between the primary buds and the cotyle- 

 flons. A similar arrangement occurs in certain species of 

 Ephedra. 



The same arrangement of parts is to be found in the 

 ordinary buds of G. Gnemon, and in the old plant of this 

 species growing at Kew axillary buds have developed into 

 foliage shoots in a single instance on the strong main axis. 

 Though this is of frequent occurrence in some species of 

 Ephedra it seems to be the exception in G. Gnemon. 



^\ hile these structures are young they are enclosed and 

 covered in by swellings at the base of the petiole (fig. 19). 

 Immediately above the young parts thus enclosed the peri- 

 pheral tissues of these swellings are subject to a gummy de- 

 generation of their walls, and the epidermis and part of the 

 ^ubadjacent parenchyma become disorganised; the place of 

 the cells thus broken down is taken by fresh tissue derived 

 from an actively dividing layer, which defines the glandular 

 structure from the tissues beneath it. A mass of gummy 

 substance is thus formed, which covers and protects the 

 structures of the bud while growing. The first tangential 



