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Show 332 DROSOPHYLLUM LUSITANICUM. CHAP. XV. CHAPTER XV. DnOSOPHYLLt:'M-HORIDULA-BYBLIS-GLANDULAR HAIRS OF OTHER PLANTS- CoNCLUDING REMARKS ON 'l'IJE DnosERACE.lE. Drosophyllum- Structure of leaves-Nature of the secretion -Manner of catching insects-Power of absorption -Digestion of animal substances- Summary on Drosophyllum- Rori<.lula- ByLlis _ Glandular hairs of other plants, their power of absorption_ Saxifraga- Primula- Pelargonium- Erica- Mimbilis - Nicotiaua -Summary on glandular hairs- Concluding remarks on tho Droseracere. DROSOPHYLLUM LUSITANICUM.-This rare plant has been found only in Portugal, and, as I hear from Dr. Hooker, in Morocco. I obtained living specimens through the great kindness of Mr. W. C. Tait, and afterwards from Mr. G. Maw and Dr. Moore. Mr. Tait informs me that it grows plentifully on the sides of dry hills n·ear Oporto, and that vast ntnnbers of flies adhere to the leaves. This latter fact is well known to the vill~gers, who call the plant the "fly-catcher," and h~ng It up in their cottages for this purpose. A plant In my hot-house caught so many insects during the early part of April, although tho weather was cold and insects scarce, that it must have been in some manner strongly attractive to the1n. On four leave~ of a young and small plant, 8, 10, 14, and 16 minute insects, chiefly Diptera, were found in the autumn adhering to them. I neglected to examine the roots, but I hear fro1n Dr. Hooker that they are v.ery small, as in the case of the previous! y mentioned members of the same family of the Droseracero. 'I' he leaves arise from an almost woody axis ; they CHAP. XV. STRUCTURE OF LEAVES. 333 are line.ar, much attenuated towards their tips, and several inches in length. The upper surface is concave, the lower convex, with a narrow channel down the middle. Both surfaces, with the exception of the channel, are covered with glands, supported on pedicels and arranged in irregular longitudinal rows. These organs I shall call tentacles, from their close resemblance to those of Drosera, though they have no power of movement. Those on the same leaf differ much in length. The glands also differ in size, and are of a bright pink or of a purple colour; their upper surfaces are convex, and the lower flat or even concave so that they resemble miniature mushrooms in appear-' ance. They are formed of two (as I believe) layers of delicate angular cells, enclosing eight or ten larger cells with thicker, zigzag walls. Within these larger cells there are others marked by spiral lines, and apparently connected with the spiral vessels which run up the green multicellular pedicels. The glands secrete large drops of viscid secretion. Other glands, having the same general appearance, are found on the flowerpeduncles and calyx. Besides the glands which are borne on longer or shorter pedicels, there are numerous ones, both on the upper and lower surfaces of the leaves, so small as to be scarcely visible to the Fw. 14. naked eye. They are colourless and (D1·osophyllum zusi-tanicum.) almost Sessile, either circular Or oval Part of leaf, enlarged i tl' th 1 seven times, show- n ou lne; e atter occurring chiefly ing lower surface. on the backs of the leaves (fig. 14). Internally they have exactly the same structure as the larger glands which are supported on pedicels |