144 
CONTRIBUTIONS TO BOTANY. 
dicbaud and Griffiths in Gnetum. From the above facts, it will 
be seen that the seed of Ephedra is quite atropous, and (if we 
except the formation of the tubillus) little different in its entire 
structure from that of many of the Urticacece. 
I have thus detailed minutely the floral and seminal structure 
of Ephedra, in proof of Blume’s declaration that the Gnetacea 
possess a much higher degree of organization than any of the 
so-called Gymnospermous families. This structure of Ephedra 
ofi’ers great analogy to that of Gnetum, from which it differs in 
the relative numbers, sizes, and position of the male and female 
flowers, in the form of its floral envelopes, in the number of its 
anthers, and in the relative size of the radicle and cotyledons. 
In Gnetum the flowers are arranged in distant nodes, each node 
consisting of one general, short, cup-shaped involucre, which en- 
circles the stem, and supports two close whorls of numerous 
florets crowded together, each in a single series, the lower series 
being composed of female florets, the upper one of male florets : 
in the female series the perianthium is reduced to lacerated 
scales that surround each ovary ; in the male flowers, which have 
only a single stamen, each is contained within a 2-4-fid perigo- 
nium. I have not seen its fruit and seed, which are minutely 
described by Griffiths : it grows to a size many times larger than 
that of Ephedra, often attaining the dimensions of a plum, the 
ovary from which it originated being extremely minute. Ana- 
logy shows that each involucel of the spikelet in Ephedra is a 
verticil composed of two opposite bracteiform leaflets standing in 
front of each perigonium, and which are connate at their base. 
In Gnetum, where, instead of two, more than a score of florets 
are congregated in each verticil, these bracts become wholly 
agglutinated together by their margins into an entire cupular 
and annular general involucre. We find the precise homologues 
of such gamophyllous involucels in the Nyctaginaceee, Thyme- 
leacece, Polygonacea, &c. 
No one has yet noticed the condition of the ovary of Ephedra 
at the period of its fructification, nor any of the intermediate 
stages of its growth into a mature seed ; nor has any botanist 
remarked its different gradations in Gnetum, except Griffiths, who, 
in the posthumous memoir before mentioned, minutely detailed 
this growth. According to that excellent observer*, the produc- 
tion of the tubillus does not commence till after the impregna- 
tion of the nucleus, when the micropylar mouth of the tegmen 
gradually expands and finally becomes elongated into a narrow 
open tube, which becomes protruded far beyond the apex of the 
pericarp, as we find it in Ephedra ; according to his report, there 
IS at first no constriction in this tubillus, which remains unclosed 
* Linn. Trans xxii. 301, tab. 55. figs, 18 & 20. 
