Influence of the Adult Plant upon the Seedling. 323 
The number of seed-leaves in these plants varies ; Fletcher, in 
the case of Persoonia lanceolata, found the range to be between 
three and five. Although we have not had the opportunity of 
examining Persoonia pinifolia, P. lanceolata being the only species 
available for our investigation, some figures relating to the variation 
in the number of the cotyledons of the former plant may be quoted, 
since we have used it as a basis for comparison (Table p. 322). 
It will be observed that the range is somewhat wider in P. 
pinifolia than in P. lanceolata, but not quite so wide as in Pinus 
sylvestris. 
In the paper referred to, Fletcher gives further examples of a 
similar kind. It is thus seen that the Proteaceae in their poly- 
cotyledony closely resemble many Gymnosperms, more especially 
those with acicular leaves; and this suggests that marked poly- 
cotyledony may possibly be connected with this particular coniferous 
form of xerophily. 
Structure of the Cotyledons. 
The resemblance to certain Gymnosperms is, perhaps, even 
more striking when the internal structure is examined. The fleshy 
cotyledons are covered with a well-defined cuticle, the epidermis is 
quite normal, but the stomata, which are flush with the general 
level of the surface, are characterised by the presence of two sub¬ 
sidiary cells, one on each side of and parallel with the guard-cells. 
This is a feature which we have not observed in any Gymnosperm. 
The mesophyll of Persoonia does not shew much differentiation ; 
in young cotyledons and in the more apical parts of older ones the 
mesophyll consists of undifferentiated parenchyma; but in the 
middle and basal regions, the peripheral cells may shew a certain 
amount of radial elongation so that the chlorenchyma may be more 
or less clearly differentiated into palisade and spongy parenchyma. 
This, possibly, may be more strongly marked in old seed-leaves. 
The chlorophyll-containing cells of the cotyledons, as also in 
Gymnosperms, have not the internal flanges characteristic of the 
adult foliage of many Coniferae and also some Proteaceae, e.g., 
Persoonia juniperina ; nor are resin ducts present, a feature, it will 
be remembered, not at all general in the cotyledons of Gymno¬ 
sperms at large. 
Each seed-leaf of Persoonia lanceolata is traversed by a single 
vascular strand, a point of resemblance to many Cupressineae and 
• Abietineae; it must, however, be remarked that in some cases the 
bundles of the cotyledons of Persoonia do shew a tendency to 
