Narrative of a Survey of the Intertropical and Western Coasts of Australia — Vol. 2: Performed between the years 1818 and 1822King, Philip Parker
History
Narrative of a Survey of the Intertropical and Western Coasts of Australia — Vol. 2: Performed between the years 1818 and 1822
King, Philip Parker
Australia -- Description and travel; Natural history -- Australia
In addition, however, to the difference in texture of the outer coat of
the seed, and in those other points, on which I then chiefly depended in
distinguishing Junceae from Asphodeleae, a more important character in
Junceae 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.
OBS. 3.
ON THE STRUCTURE OF THE UNIMPREGNATED OVULUM IN PHAENOGAMOUS PLANTS.
The description which I have given of the Ovulum of Kingia, though
essentially different from the accounts hitherto published of that organ
before fecundation, in reality agrees with its ordinary structure in
Phaenogamous 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; in tending hereafter 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 Embryo. 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.
(*Footnote. Flinders Voyage 2 page 601, and Linnean Society Transactions
12 page page 136.)
In the Botanical Appendix to the account of Captain Flinders' Voyage,
published in 1814, the following description of the Ovulum of Cephalotus
follicularis is given: Ovulum erectum, intra testam membranaceam
continens sacculum pendulum, magnitudine cavitatis testae, and in
reference to this description, 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."*
(*Footnote. Flinders Voyage loc. cit.)
My attention had been first directed to this subject in 1809, in
consequence of the opinion I had then formed of the function of the
Chalaza in seeds;* and sometime before the publication of the observation
now quoted, I had ascertained that in Phaenogamous plants the
unimpregnated Ovulum very generally consisted of two concentric
membranes, or coats, enclosing 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 always agreed in
direction with the nucleus. And, lastly, that at the apex of the nucleus
the radicle of the future Embryo would constantly be found.
(*Footnote. Linnean Society Transactions 10 page 35.)
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