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Show 390 PINGUICULA GRANDIFLORA. CHAP. XVI. ainount of pollen must be blown from ~he many wind-fertilised carices, grasses, &c., growing where Pinguicula lives, on to the leaves thickly covered with viscid glands and forming ~arge rosettes. Even ~ few grains of pollen on a single gland causes It to secrete copiouslv. We have also seen how frequently the sm~ll leaves of Erica tetralix and of other plants, as well as various kinds of seeds and fruits, especially of Carex, adhere to the leaves. ?ne leaf of the Pinguicula had caught ten of the httle leaves of the Erica ; and three leaves on the same plant had each caught ~ seed. Seec~s subj~cted to the action of the secretion are sometimes killed, or the seedlings injured. We may, therefore, conclude that Pinguicula vulgaris, with its small roots, is not only supported to a large extent by the extraordinary number of insects which .it habitually captures, but likewise draws some nourishment from the pollen, leaves, and seeds of other plants which often adhere to its leaves. It is therefore partly a vegetable as well as an animal feeder. PINGUICULA GRANDIFLORA. This species is so closely allied to the last that it is ranked by Dr. Hooker as a sub-species. It differs chiefly in the larger size of its leaves, and in. t~e glandular hairs near the basal. part . of the. m1~nb being longer. But it likewise differs ~n constitutiOn; I hear from Mr. Ralfs, who was so kind as to send Ine plants from Cornwall, that it grows in rath:r different sites; and Dr. Moore, of the Glasnevm Botanic Gardens, informs me that it is much more manageable under culture, growing freel~ and flowering annually ; whilst Pinguicula vulgar~s has to be renewed every year. Mr. Ralfs found numerous CHAP. XVI. PINGUICULA LUSITANICA. 391 insects and fragments of insects adhering to almost all the leaves. These consisted chiefly of Dipt ra, with some Hymenoptera, Homoptera, Coleoptera, and a moth. On one leaf there were nine dead insects, besides a few still alive. He also observed a f w fruits of Oarex pulicaris, as well as the seeds of this sanw Pinguicula, adhering to the leaves. I tried only two experiments with this species; firstly, a fly was plac <l near the margin of a leaf, and after 16 hrs. this ·wa · found well inflected. Secondly, several small flies were placed in a row along one margin of another leaf, an<l by the next morning this whole margin was curlo(l inwards, exactly as in the case of Pinguicala vulgaris. PINGUICULA LUSITANICA. This species, of which living specimens were sent m by Mr. Ralfs from Corn wall, is very distinct from the two foregoing ones. The leaves are rather sn1aller, much more transparent, and are marked with purple branching veins. The margins of the leaves are much more involuted; those of the older ones extending over a third of the space between the midrib and the outside. As in the two other species, the glandular hairs consist of longer and shorter ones, and have the same structure; but the glands differ in being purple, and in often containing granular matter before they have been excited. In the lower part of the leaf, aln1ost half the space on each side between the midrib and margin is destitute of glands; these being replaced Ly long, rather stiff, multicellular h~irs, which intercross over the midrib. These hairs perhaps serve to prevent insects .fron1 settling on this part of the leaf, where there are no viscid glands by which they could be caught; but it is hardly probable that they were developed for this purpose. The spiral vessels pro- |
