356 Mr. Robert Brown on the Structire of the 
a more important character in Junceze exists in the position of 
the embryo, whose radicle points always.to the base of the 
seed, the external umbilicus being placed in the axis of the 
inner or ventral surface, either immediately above the base as 
in Kingia, or towards the middle, as in Xerotes. 
Ops. III.—On the Structure of the UNIMPREGNATED Ovu- 
LuM in Phenogamous Plants. 
The description which I have given of the Ovulum of Kingia, 
though essentially different from the accounts hitherto pub- 
lished of that organ before fecundation, in reality agrees with 
its ordinary structure in Phanogamous plants. 
I shall endeavour to establish these two points; namely, the 
agreement of this description with the usual structure of the 
Ovulum, and its essential difference from the accounts of other 
observers, as briefly as possible at present; intending here- 
after to treat the subject at greater length, and also with other 
views. 
I have formerly more than once* adverted to the structure 
of the Ovulum, chiefly as to the indications it affords, even 
before fecundation, of the place and direction of the future Em- 
bryo. These remarks, however, which were certainly very 
brief, seem entirely to have escaped the notice of those authors 
who have since written on the same subject. 
In the botanical appendix to the account of Captain Flin- 
ders’s Voyage, published in 1814, the following description of 
the Ovulum of Cephalotus follicularis is given: ‘¢ Ovulum erec- 
tum, intra testam membranaceam continens sacculum pendu- 
lum, magnitudine cavitatis teste,” and in reference to this de- 
scription, I have in the same place remarked that, “ from the 
structure of the Ovulum, even in the unimpregnated state, I 
entertain no doubt that the radicle of the Embryo points to 
the umbilicus +”. 
My attention had been first’ directed to this subject in 1809, 
in consequence of the opinion I had then formed of the func- 
tion of the Chalaza in seeds}; and some time before the pub- 
lication of the observation now quoted, I had ascertained that 
in Phenogamous plants the unimpregnated Ovulum very ge- 
nerally consisted of two concentric membranes, or coats, In- 
closing a Nucleus of a pulpy cellular texture. I had observed 
also, that the inner coat had no connexion either with the 
outer or with the nucleus, except at its origin; and that with 
relation to the outer coat it was generally inverted, while it 
* Flinders’s Voyage, vol. ii. p. 601, and Linn. Soc. Trans. vol. xii. p. 136. 
+ Flinders’s Voy. loc. cit. t Linn. Soc. Trans. vol. x. p. 35. 
always 
