Evolution of the A ngio sperms. 501 
In Gnetum , the condition of affairs is very different. The strobili are 
borne on special branches, which at first sight have some resemblance to 
slender, solitary spikes or to a panicle of spikes. Each fertile branch, how- 
ever, bears numerous strobili arranged in whorls, subtended by pairs of 
bracts. On the female branches, 3-8 strobili are found in the whorl, while 
on the male, as many as 40 may occur. Numerous hair-like structures 
occur between the strobili. It would appear probable that the real 4 in- 
florescence \ or rather the aggregation of strobili in Gnetum , is of a com- 
pound nature and a complicated type, and at the same time much 
compressed. The whole may be not inaptly compared with the com- 
pressed cymes of certain Labiates, such as Lamium . 
It is not our object to consider these aggregates here in detail. 
It is significant, however, to note that the reduced fructifications are arranged 
in dense, and sometimes complicated, aggregates ; a combination of cir- 
cumstances also met with among some of the more highly modified 
Angiosperms, such as the Amentiferae. That such a comparison implies 
nothing more than a parallelism of development is apparent when we bear 
in mind that we are here contrasting pro-anthostrobili with eu-anthostrobili. 
We may also point out that as regards the strobili themselves, apart 
from their aggregates, the parallelism between the two groups is very close. 
Those of Ephedra and Welwitschia find their analogues in the Salicaceae. 
The female fructifications of Welwitschia correspond to those of Populus in 
that the strobili are aggregated into spikes, each strobilus being subtended 
by a bract. A gamophyllous perianth is also present (Text-fig. 2). They 
differ, however, in the absence of megasporophylls and in the fact that 
solitary ovules alone occur. Both the male and female strobili of Ephedra 
also correspond with the flowers of Populus , with the same differences, and 
with the additional exception that the microsporophylls are less numerous. 
While not wishing to press too closely a comparison between the two 
groups, which we think is founded merely on a parallelism of development, 
we may, however, point out the interesting fact that an almost exact 
homoeomorph of the male strobilus of Welwitschia has recently been dis- 
covered in the amphisporangiate flower of an Indian Poplar, Populus glauca , 
Haines. 1 The flower of this species corresponds very closely with the male 
pro-anthostrobilus of Welwitschia , except that the number of stamens is 
greater, and that the female organ is functional. 
The Microsporophylls and Microsporangia. 
We may. now turn our attention briefly to the male organs of the 
Gnetales, which, though differing unmistakably from the stereotyped form 
of the Angiospermous stamen, yet more closely resemble it than the 
1 Haines (’06) ; see also Arber and Parkin (’07), p. 41 . 
