OF THE DIPTEROCAEPACEZ, 15 
of which seeds were available for examination. The variety is so 
great that any attempt at classification is exceedingly difficult. 
Species otherwise closely allied show great differences in the 
structure of the embryo. Speaking very broadly, the following 
types may be distinguished, but they in no way exhaust the great 
variety of structure that is actually found :— 
I. The cotyledons are thick, fleshy, plane-convex, entire or 
bifid, the hypocotyl being imbedded between them on the 
face of contact. Vatica (section Retinodendron), Isoptera, 
Vateria. The hypocotyl varies in length. It is short, 
enclosed between the auricles of the cotyledons (Vatica 
Schumanniana, Gilg). It is as long as the embryo, and 
consequently the attachment of the cotyledons is near the 
base of the fruit-cavity (Vatica Roxburghiana). It has 
about half the length of the embryo, the cotyledons being 
attached to it about the middle of the seed ( Fatica obscura, 
Trimen, V. lanceefolia, Blume, V. moluccana, Burck). 
II. The cotyledons are flat, but many times folded and twisted, 
III. 
the whole often appearing as a homogeneous mass, in 
which the radicle alone can be distinguished. The testa 
enters into the folds of the cotyledons.  Radicle short. 
Dipterocarpus, Doona. 
The cotyledons are fleshy, but they are bent or folded 
along their midrib or median line. The outer cotyledon 
is concave, more or less embracing the inner (Engler, 
Natürl. Pflanzenfamilien, iii. 6. fig. 118 B, 120 G, H). 
The hypocotyl is situated between the augicles or the 
lobes of the outer cotyledon, which may be termed the 
radicular. The lignified placenta is more or less enclosed 
by the inner, which may hence be called the placentar 
cotyledon. The radicle lying on the outside, the placenta 
being in the main axis of the fruit, the radicular may also 
be termed the anterior, and the placentar may be called 
the posterior cotyledon. The embryo of this type varies 
according to the length of the hypocotyl: it is short in 
Dryobalanops, Parashorea, Pentacme, Vatica astrotricha 
(Synaptea), and several species of Shorea; it is long in 
Anisoptera, Hopea, species of Shorea of sections Eushorea, 
Anthoshorea, and Pinanga. 
Stemonoporus and Cotylelobium have their cotyledons divided 
