Pitchered Insectivorous Plants. 
259 
leaflets showing dorsal fusion in their upper region ; second, 
the midrib is prolonged as a tendriliform structure ; third, the 
midrib opens out to receive a dorsal involution of itself from 
above, and carries on its sides two wing-like leaflets showing 
dorsal fusion distally ; fourth, above the involution the midrib 
carries two leaflets which by an exaggerated dorsal fusion 
form the lid ; fifth, the midrib now reduced to a filiform pro- 
cess may next give off two very small lateral leaflets ; sixth, it 
may produce a dorsal median process which probably repre- 
sents two lateral leaflets with dorsal fusion. The midrib then 
runs out into a fine point. 
The mode of formation of the corrugated margin is easily 
explained. It results from flattening out of the orifice rim 
externally and internally and curving over of each upon itself. 
The remarkable species N. Loivii (for pitchers of which I am 
indebted to the kindness of Mr. Burbidge, of Trinity College 
Gardens, Dublin, and Mr. Veitch of Chelsea) retains, as I will 
point out more in detail afterwards, the primitive condition of 
a simple rim, and the marginal glands of Dickson are disposed 
round it with exposed orifices, the whole being beautifully 
illustrated in Hooker’s figure of the species 1 . 
HELIAMPHORA. 
This is a genus of low growing plants and includes only 
one species, H. nutans , which forms rosettes of leaves close 
to the ground. These having no need of supporting tendrils 
may be said in some respects to remain permanently in the 
condition of seedling Nepenthes leaves. If a young leaf one 
or two inches in length be examined it will be seen that in 
it, as in Nepenthes , there is a basal portion consisting of a solid 
midrib with lateral laminae ; in both the midrib vascular tissue 
then spreads out to form the framework of the pitcher cavity ; 
here also the front of the pitcher has two continuations upward 
of the basal lamina which project as two dorsal wings. Most 
of the vascular tissue also which has opened out curves round 
1 Trans. Linn. Soc., Vol. XXII (1859). 
