IN FLOWERING PLANTS. i21 
14. Same, pistillum not open. 
15. Stamen, outer view: 16. ditto inner: 17. ditto after 
dehiscence : 18. pollen, immersed in water : 19. ditto 
opaque. 
20. Ovule, after fecundation laid open; a. testa; b. apex 
of secundine; c. nucleus ; d. embryonary sac; e. em- 
bryo ; f.* boyaux here branched. | : 
21. Embryonary sac of ditto ; a.* embryo 
22. Apex of ditto with embryo mostly included ;.. 
Albumen. Perisperm. Endosperm. 
'This substance has been, but I think erroneously, suppos- 
ed by all Botanists to exist at some period or other in every 
seed. For even during the first period of its deposition, its 
appearance is very different from that presented by the very 
lax tissue contained in embryonary sacs when membrano- 
cellular and surrounding the embryo. 
In its earlier stages it consists of myriads of active mole- 
cules of irregular sizes, those mysterious bodies which evi- 
dently play so important a function in all cases of formation 
of new organs. : 
This organ is, with the exception of the few instances. 
mentioned by Mr. Brown, invariably formed within the em- 
bryonary sac. 
M. Brongniart has noticed several additional instances in 
which he supposes the albumen to be formed within the 
nucleary tissue. Of the instances given, Zea is not a true 
example, and from the consideration of Santalum, I would 
infer that even in Thesium, development of albumen follows 
the ordinary course. 
With regard to Zea, I am of opinion, that M. Brong- 
niart has not examined the ovula at a sufficiently early 
period. , 
'This distinguished Botanist has, it appears to me, des- 
cribed the nucleus as the single integument, and the em- 
bryonary sac as the nucleus. It must be remarked, that from 
* Letters of reference omitted in original. 
