267 
rated from the sterile leaves, but pass over into them 
gradually. Only in the middle region of the strobilus itself 
the sporophylls are fertile, the uppermost pair being sterile 
and fused, forming a columella-like structure. One or two 
ovules are borne on their apical side, with their micropyle 
directed towards the axis of the strobilus. 
In a young stage of development, two lips can be seen 
at the micropyle, but they are not always clearly marked. 
The ripe seeds have an oblong shape and are round 
in transverse sections. Their integument again is differen- 
tiated in the three layers, surrounding the entirely free 
nucellus. 
Both the outer layer and the endotesta are thin and 
only represented by dry papery membranes, whereas the 
sclerotesta is very hard and occupies the greater part of 
the testa. 
Of the 46 examined seeds 30 were triangular in their 
upper portion, having like the other lenticular ones small 
membranous wings on the ribs. 
In transverse sections just below the micropylar region, 
sutures are to be seen corresponding with the angles on 
the outer surface. In the mature condition the nucellus, 
contrary to Callitris, is represented by a thin dry envelop- 
ment only, surrounding the embryo. 
$ 24. Pinus. 
Literature: Baillon (10, 11), Bessey (22), Brogniart 
(26), Caspary (32), Celakovskÿ (39, 42, 44), 
D'elpanomst ME ichler (62) "Elerz£eld|(71); 
Parlatore (108, 109), Schumann (131), Stenzel 
(143), Tubeuf (160), Velenovskv (163), Will- 
komm (172), Worsdell (175). 
Recueil des trav. bot. néerl. Vol. XVII. 1920. 18 
