538 Gibbs . — On the Development of the 
leaves unusually delicate in texture and dark in colour, with silvery under- 
sides. It is general in forests throughout the country, up to 2,000 ft., accord- 
ing to Cheeseman ( 14 , p. 651), who describes the wood as hard and durable. 
The flowering shoots, both cd and $ , are exceedingly numerous, but 
both in the Ohakune and Nelson material the ovules were mostly attacked 
by some insect grub, aborted and abnormally swollen. 
Miyake, in Abies balscimea ( 33 , p. 134), describes more than half the 
ovules examined as being infested by insect larvae ; in early stages they 
were impossible to distinguish from those not infested. In the present 
instance P. vitiensis ( 1 . c., p. 536) was found to be similarly infected. In 
a purely endemic species limited to a small country, where even in its 
native habitat it is only of local occurrence, such infection, spread over a 
series of years, would very soon work out its extinction. This is the 
case in California with Pinus radiata , now practically limited to the 
Monterey Peninsula, and to more or less isolated groups through the coast 
country, where it is subject to specialized insect attack. In accounting for 
the dominance or recession of species this very evident but passive factor, as 
far as the plant is concerned, is as a rule neglected, and most emphasis is laid 
on the possible active participation of the plants themselves in the struggle 
for existence, the survival of the fittest being attributed to superior organiza- 
tion and response to ontogenic requirements or to natural selection. 
The flowering shoot consists of an elongated axis, borne in the axils 
of the foliage leaves of the young wood (PL L, Fig. 19, strob .). The shoots 
show the protective bud scales at the base ; these are succeeded by apparently 
opposite and decussate modified leaves, an arrangement subsequently lost 
with the elongation of the axis. The laminae of these modified leaves are 
suppressed, the bases being adpressed to the stem axis (P'ig. 20, /.). 
That these are modified leaves is shown in Fig. 21, where the laminae have 
grown out as ordinary foliage leaves. These leaves, as a rule reduced to 
their bases, are followed by the fertile bracts, exactly similar in structure, 
with the bases fused with the axis and laminae more or less suppressed. 
Above the bracts is an apical bud (Fig. 20, ap. bud) always pressed to one 
side by the development of the last fertile bract. 
Pilger ( 40 , pp. 13, 14) describes the ? flower in this species as a spike, 
consisting of a short limited branch, with a thin axis, bearing spirally 
arranged scale leaves at equal distance on it, which run down the axis, 
and at their base bear each an ovular rudiment. He describes the 
branch as bearing only ‘carpels’, but this ‘ Verhalten ’ is often modified 
so that the lowest leaves may be sterile. In the present instance the sterile 
leaves were invariably found to be present, as described above (Figs. 19, 
20, 21, /.). The fertile bracts are given by Pilger as about 8, whereas 
Cheeseman ( 14 , p. 650) gives them as 2-8. 
In the present investigation, one axis was found with one fertile bract 
