36 BOTANICAL GAZETTE [JULY 
it is free to the base of the nucellus (fig. 14; Norén, l. 1, fig. 5). 
The arms of the integument are composed of three to five layers of 
cells. The micropyle is wide and deep, and no depressed pollen 
chamber is present until after pollination. The nucellar cap is com- 
posed of large clear cells, which in the upper layer project up, thus 
giving a jagged or irregular outline to the top of the cap. The cells 
beneath these are smaller, more nearly isodiametric, are arranged 
concentrically, and contain large darkly staining nuclei (jg. 14). 
Norén does not find this concentric arrangement until after pol- 
lination. 
At the time of pollination, a drop of clear liquid resembling a 
crystal bead is deposited on the top of each of the three ovules. It 
is probable that the pollen falls on this drop and is drawn down into 
the micropyle by the drying of the liquid, as has been described for 
other gymnosperms. The closing of the micropyle is brought about — 
by the rapid elongation of the inner row of cells of the arms of the 
integument. Occasionally the two arms meet in a straight line 
(jig. 15), as in Pinus (FERGUSON 7). More often, however, the arms 
dovetail together (jig. 16), also figured by Nor&n. By this method 
the micropyle is even more securely closed. Following the elongation 
of the cells cross-walls are laid down, cutting the lengthened cells into 
smaller ones. COoKER (5) describes a similar elongation of the innef 
row of cells in Taxodium, while Miss FERGUSON (7) finds it in the 
middle row of cells in Pinus, and Lawson (16) states that in Cryp- 
tomeria japonica the subepidermal and the epidermal rows both elon- 
gate. Norn reports that the closing of the micropyle in J. communis 
has recently been described by Kusart (13), but I have not seen this” 
paper. 
Soon, in the lower part of the nucellus, several faintly staining cells 
appear, the so-called spongy tissue of STRASBURGER. It is one of 
these cells that, in the following spring, is differentiated into the macro 
spore mother cell. It is very probable that it was the presence of this 
spongy tissue which led HoFrMEtsTER (8) to the opinion that the macro 
spore mother cell developed in early summer. Norén says that usually 
the macrospore mother cell could be distinguished by the beginning 
of July, but that occasionally two or four cells enlarge, and then it is 
impossible to tell which is the macrospore mother cell until the follow- 
