44 MESSRS. NEWELL ARBER AND J, PARKIN ON 
In trying to arrive at some conclusion with regard to the primitive form of 
the various organs of the Angiospermous strobilus, we have found it helpful to 
endeavour to conceive a mental picture of a flower in which all the members 
were alike primitive. We, however, by no means wish to infer that such a 
flower ever existed, for, as we have pointed out above (p. 35), this would be 
contrary to the general trend of evolution, since corresponding stages in the 
differentiation of the various organs of a seed-plant, at any one point of time, are 
~ 
Fig. 1. 
An Angiospermous strobilus or flower in which the perianth, microsporophylls and mega- 
sporophylls, two of the latter being shown in longitudinal section, are represented as if 
in the primitive condition. This cone is entirely imaginary, and in all probability 
never existed. 
dissimilar. Such a strobilus (see fig. 1) would consist of a large, elongated, 
conical axis bearing megasporophylls above and microsporophylls below. 
At the base of the cone, a well marked perianth would be found, con- 
sisting of sterile, leaf-like members, affording protection to the cone as a 
whole, and playing some part in the mechanism for insuring cross-fertilisation 
by adding to its conspicuousness. All the organs of the cone would be of 
large size, numerous or indefinite in number, and spirally arranged. The 
cone would be solitary, borne either terminally or axillary. 
