THUJA. 21 
3. Do. longitudinal section, a testa, b nucleus, c cavity. 
4. Longit. section of nucleus, a nucleus, 4 sac lining the 
cavity. 
5. Membrane separated partially. 
B.—Fig. 1. seed inverted. 
2. Do. long section, a testa, b exostome, c nucleus. 
3. Long section of nucleus, a embryo. 
4. Nucleus more advanced. 
5. Ditto long section, a embryo. 
6. Embryo removed. 
TnuvJa. 
Thuja occidentalis, Pl. CCCLXXVIII. Fig. I, IT, III. 
The transition from the bractez clothing the peduncle of 
the galbulus of Thuja occidentalis, to the squame, is by no 
means abrupt. 
In this genus there is a tendency towards completion of 
the carpella, the sides being prolonged beyond the real apex 
which is indicated by a prominence, the margins of which are 
transversely decurrent, if I may be allowed so strange an 
expression; judging from this tendency, we might expect to 
find a coniferous plant the seeds of which are not naked, in 
such a case, the fruit would be compound consisting of many 
simple single-seeded carpella. 
The ovula in this genus are attached by a broad base, in 
a very young state they are marginal. The apex is attenuate 
the exostome large and irregular. The ovule is not very un- 
like a square flask. In all the specimens I examined, and 
which were all abortive, the primine was thick and osseous. 
The nucleus occupying the lower part of its cavity, being at- 
tached by a broad base. The apex is depressed and most 
distinctly areolate. Ata later period and indeed when the 
galbulus appears perfect, the ovula are of considerable size, 
ovate, angular and somewhat curved. The testais osseous and 
its exostome denticulate, the nucleus now occupies the 
