Insectivorous Plants ( Part II). 407 
abundance ; and ( 3 ) those with the mouth closed by the lid, 
into which rain can hardly, if at all, find ingress. But while 
in some respects this is a convenient physiological classifica- 
tion, I think it may be considered that the species now living 
group themselves round some extinct form most nearly 
related to 5. variolaris. This view is favoured, alike from 
the standpoint of seedling pitcher-structure, as pointed out 
by Professor W. P. Wilson 1 , from the structure of adult 
pitchers, and also from coloration and relative complexity 
of the floral parts. It will be seen, as we describe the minute 
anatomy, that 5. variolaris is the most generalized form now 
known to us, and that from some simpler type one advancing 
line branches off to S.Jlava , X. Drummondii , and 5. rubra ; 
another leads to 5. purpurea , and still another to 5. psittacina . 
By viewing them thus we can, I think, bring into harmony 
their resemblances and differences in leaf-form, minute 
anatomy, and floral development, and they will accordingly 
be examined in the order just given. 
But before treating of the species separately I may point 
out that the protective winter bud-leaves show many honey- 
glands, particularly over their outer surface. The question 
naturally suggests itself, Why should these be provided 
with an alluring surface ? I think the answer is found if we 
view them as the earliest formed of the annual rosette of 
pitchered leaves which for protective purposes have become 
reduced in size and have failed to pitcher. They would 
represent, in fact, such a leaf as I have figured in Plate XVII, 
Fig. 8, of the Annals of Botany, Vol. Ill, but in a greatly more 
reduced state 2 . There it is compared with a pitchered leaf. 
vS\ variolaris . The external pitcher-surface in this species 
is covered with short, stout, blunt hairs, each formed by 
the bulging out of an epidermal cell. These are directed 
outwards or obliquely upwards, are shortest and most scat- 
tered towards the base, and increase in size and regularity 
1 Proc. Philadelphia Acad. Nat. Science, 1888. 
2 Goebel adopts this view also, and his interesting observations on the relation 
of scale-leaves and foliage-leaves (Bot. Zeitung, 1880) may be said to establish it. 
