IN CEYLON. 
61 
ovalifolia there is no splitting of the testa, and it is impossible 
for an expanded cotyledon to effect its exit from such a 
small circular micropylar opening amply filled by the 
thin axis of the hypocotyl ; in other species there is only a 
partial splitting, and even in calamander seeds the gap is 
never large enough to allow the cotyledons to escape 
intact. 
Since the splitting of the testa would be more complete if 
the endosperm were exhausted more quickly, it follows that 
probably all the forces mentioned above play some part in the 
final detachment of the cotyledons. 
The mode of development just described is not a conse¬ 
quence of the artificial raising of the seeds ; the detachment 
occurs in nature, and the internal characters of the epicoty- 
ledonary and cotyledonary traces indicate that this line 
of development has been habitual for a considerable period 
of time. This mode of development is characteristic of some 
of our rarest species, and is probably one of the factors which 
is leading to the extinction of many species. 
The detachment of the cotyledons is attended with the 
minimum disadvantages in those species having short hypo- 
cotyls (D. insignis and D. Embryopteris). In these instances 
the seed coat, endosperm, and cotyledons are but rarely 
raised above the surface of the soil, and the young though 
enhanced epicotyledonary parts gain easy exit. 
The habit of D. insignis in particular is very suggestive of 
a hypogeal tendency, since the seeds are rarely raised above 
ground, the hypocotyl is very short, and the epicotyl stem 
very long and provided with small leaf rudiments suggestive 
of typical Garcinia seedlings. 
The morphological relationships of the parts of the seed¬ 
lings are also of interest. In the first case it is worthy 
of note that in those species possessing short hypocotyls the 
epicotyledonary axis is usually long (4 to 7 cm.), whereas 
in those having hypocotyls of normal length the epicotyle¬ 
donary axis is usually only from 0*5 to 1*5 cm. in length. 
