CONTRIBUTIONS TO BOTANY. 
159 
lacerated ; but, when uninjured, I have found it shortly 2-fid, 
with two small erect rounded lobes, differing in no respect from 
what is observable in his section Plagiostoma. I therefore con- 
sider that such a division of the genus, founded upon the cha- 
racter assumed, is not maintainable. 
I have expressed a doubt [ante, p. 142) of the truth of the 
general belief that in Ephedra the flowers are dioecious, that 
is to say, that the male and female flowers are always upon di- 
stinct plants. I have stated the impression entertained by me 
when in Chile, that both sexes exist on the same plant, if not in 
the same spikelets : in support of this, my drawing of Ephedra 
bracteata, made nearly forty years ago, showed fruits upon one 
of the lower branchlets, while all the upper ones exhibited male 
flowers only; but I was unwilling to place much reliance on 
that circumstance at this distance of time, as all my specimens 
were lost. I have, however, lately noticed a confirmation of this 
fact in a specimen, now existing in the Hookerian herbarium, 
of the same species, where most of the ramifications have their 
floral branchlets terminated by ripe fruits, while in a lower part 
is another branchlet charged with a spikelet of male flowers. 
Kunth also corroborates a similar occurrence in Ephedra ameri- 
cana : in that species, he states that each axil produces a cluster 
of four spikelets, three of which consist of male florets, while the 
other contains two female flowers ; for he adopted the view of 
Richard in considering the pericarp of each achenium as the 
indurated perigonium, end the enclosed seed with its tubillus as 
the ovary surmounted by its style. It is still a matter of doubt 
whether the two achenia generally associated in the apex of a 
spikelet are produced from one or two florets. I am inclined to 
think the latter, because it is more in analogy with the position 
of the male florets. Meyer describes four species from Southern 
Europe and Mauritania, where the fruit is constantly solitax’y in 
each spikelet : this, perhaps, is merely the result of the abortion 
of one of the florets. I have frequently met with the same 
occurrence in the South American species; but the abortive 
carpel, of small size, was invariably present. 
Careful observations on the progressive growth of the plants, 
made in their living state, are required to clear up these several 
doubts, and to complete the history of Ephedra. The following 
diagnosis of the genus is based wholly upon my own observations 
of the South- American species here described. 
Ephedra, Tournef. — Flores unisexuales ; ^ in a.xillis spicarum 
enati, mox decidui, ? semper terminales. — Flores S in spica 
amentiformi imbricato-involucrata plurimi; involucellum singu- 
lum bracteiformeimo cum opposite in vaginam brevem coalitum, 
VOL. II. 
Y 
