142 
CONTRIBUTIONS TO BOTANY. 
which it is attached; its exserted summit is flattened, fan- 
shaped, and of a greenish colour, and bears on the teeth of its 
margin about six or eight erect crowded anthers, which are ses- 
sile or borne upon very short threads ; these anthers are sub- 
globular, of a bright-yellow colour, formed of two connate cells 
separated by a partition without any connective, and opening 
by two small pores in the apex, which sometimes run into a 
transverse fissure. The pollen is spindle-shaped, and longitudi- 
nally 8-grooved. I know nothing of the structure of the ovary, 
not having seen a unisexual female spikelet in the flowering state ; 
no one has yet described it, nor do we meet with it in herbarium 
specimens until the fruit has attained its full size ; the spikelet 
has then the same number of decussating leaflets as the male 
flowers, all the lower series being empty. At the time I saw the 
living plants, I was impressed with the idea that the inflorescence 
in Ephedra is monoecious, that the fruit-bearing spikelets are 
the same as those bearing male flowers, where the persistent 
involucels have increased in size and many of them grown thicker, 
and from which the male florets have fallen away, leaving the soli- 
tary terminal male flower finally developed into two ripe carpels. 
I cannot now be certain of this fact, nor will I attempt to con- 
tradict the statement of botanists who consider the flowers to be 
dioecious ; but appearances seem to favour my earlier conviction 
that the flowers are monoecious in the same spikelets, the terminal 
flower being developed at a much later period, as often occurs 
in Euphorbiaceee. In support of this idea, it may be remarked 
that the flowers in the male involucels are developed successively 
upwards at different periods; so that before the aestivation of the 
upper florets the lower ones have fallen away, and their bract's 
have grown to two or three times their former size, thus resem- 
bling the empty imbricated involucels always found supporting 
the terminal pair of achenia in what are considered female spike- 
lets ; this fact may be seen in all herbarium specimens. The 
male flowers are constantly laterally attached, while the solitary 
female flower always forms the termination of the axis of the 
spike. The achenia are ellipsoid, sometimes much acuminated 
at the summit, flat on their contiguous sides, convex externally; 
each is terminated by a slender tubular style-like process, of 
about half its length, which has protruded through a small 
aperture in the summit of the pericarp, left by the permeable 
sessile stigma of the ovary. The pericarp is somewhat thick, 
coriaceous, and of a dark-brown colour, the mesocarpal portion 
consisting of numerous longitudinal ligneous fibres, closely com- 
pacted by scalariform tissue and fleshy matter ; it is indehiscent, 
and contains an erect seed, similar in form to, but considerably 
shorter than its cell. The seed is covered by two integuments. 
