60 ON SEEDLINGS 



The seeds of Gardenia Thunbergia vary greatly in outline, 

 being oval, oblong, orbicular or more or less angled, but 

 always much compressed and surrounded or embedded in the 

 pulp of the baccate, one-celled fruit. They owe their shape to 

 mutual compression while still young. The embryo is about 

 half the length of the endosperm, but much narrower, with 

 roundly triangular cotyledons and a terete radicle. Genipa 

 clusisefolia (fig. 430) also belongs to this type. The seeds of 

 Alberta magna (fig. 433) are oblong, bluntly trigonous and 

 conform to the cells of the ovary, of which there are four, 

 two barren and two fertile, each containing a single ovule. 

 The embryo nearly equals the endosperm in length, and is 

 situated near the dorsal aspect of the seed. The cotyledons 

 are shortly and bluntly ovate, while the terete radicle is 

 many times longer. The fruit is dry and surmounted by five 

 very unequal, foliaceous, coloured sepals, of which generally 

 two are larger than the rest, trinerved, reticulate, and rose- 

 coloured in the dry state. They seem to assist in the dis- 

 persion of the fruit. 



In two widely distinct groups of plants represented by 

 Ixora and Galium, the seeds are deeply concave or umbilicate 

 on the ventral aspect. The globular drupaceous fruit of Ixora 

 congesta (fig. 434) is two-celled with a semiorbicular seed in 

 each cell conforming in shape to the cavity. The embryo is 

 curved in conformity with the shape of the comparatively 

 thin seed ; but in other respects it closely resembles that 

 of Gardenia Thunbergia. The half-fruits of Galium Aparine 

 (fig. 439) and G. saccharatum (fig. 441) are subglobular and 

 deeply concave. The embryo is embedded in the copious horny 

 endosperm, close to the ventral aspect. The pericarp of 

 G. Aparine is dry, membranous and thin, while that of G. 

 saccharatum consists of a dense layer of dry corky tubercles. 

 The embryo of the latter is considerably narrower than that 

 of the former ; and this circumstance seems to have reference 

 to the mode of exit of the respective embryos during ger- 

 mination. 



A fourth type of seed is represented by that of Coffea 

 arabica. The fruit is oblong, drupaceous, and two-celled with 

 each cell one-seeded. The seed is large, oblong, plano-convex, 



