96 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



where we find chlorophyll developed in the cell-layers. Ultimately a thin 

 protective coating of cork is formed. Thus the ripe seed consists simply 

 of a mass of endosperm enclosing an embryo. The endosperm forms a 

 soft fleshy mass, in which are air-containing intercellular spaces, forming, 

 as Goebel suggests, an adaptation for the distribution of the seeds by 

 water, their specific gravity being thereby considerably reduced. The 

 peripheral cork-layer prevents water-logging. A similar device occurs in 

 some Water Lilies, where an additional seed- coat (the aril) forms a light 

 air- containing float. 



To sum up the results of previous work on the bulbiform seeds of 

 Amaryllide(E, we find that three forms can be distinguished, as follows : — 



A. True seeds. 1. Developed from a normal ovule, the outer integu- 

 ment of which becomes thick and fleshy after fertilisation, and forms the 

 substance of the bulbiform mass, e.g. Hymenocallis. 



2. Developed from a naked ovule, the fleshy substance being derived 

 entirely from the endosperm, which develops chlorophyll in its outer 

 layers and continues to grow for some time, e.g. Crinuvi asiaticum, and 

 other species. 



B. A vegetative groivth replacing the seed. 



3. A normal ovule is produced, but a viviparous growth of an 

 adventitious shoot and root takes place at its base, and a true bulbil is 

 formed, the ovule integuments forming the outer coats, e.g. Calostemma 

 Cunninghami. 



As regards germination, events seem to follow a course common to 

 many bulb-forming Monocotyledons (see for instance, Lubbock's 

 " Seedlings," ii. p. 578). The radicle is pushed outwards and down- 

 wards by the growth of the cotyledon, in the sheathing base of which 

 the plumule is protected ; the tip of the cotyledon remains in the seed, 

 acting as a sucker to absorb the nutritive endosperm. The formation of 

 the bulb is soon indicated by the swelling of the base of the cotyledon- 

 sheath, which forms the outermost bulb-scale. Under some circumstances 

 the cotyledon may reach a considerable length before the plumule shows 

 any sign of breaking through at its base. 



