. The natural history of plants, their forms, growth, reproduction, and distribution;. Botany. 534 ALTERATION OF FORM BY GALL-PRODUCING INSECTS. external appearance of these galls is very varied. One of the simplest forms occurs on the leaves of the Ash (Fraxinus excelsior, see fig. 362^), where it is produced by the gall-gnat Biplosis botularia. The insect having laid its eggs in the chan- nelled depressions above the leaf-veins, fleshy cushions arise on either side of the groove which meet above and roof them over. The cushions of tissue forming the roof do not fuse; their succulent edges me
. The natural history of plants, their forms, growth, reproduction, and distribution;. Botany. 534 ALTERATION OF FORM BY GALL-PRODUCING INSECTS. external appearance of these galls is very varied. One of the simplest forms occurs on the leaves of the Ash (Fraxinus excelsior, see fig. 362^), where it is produced by the gall-gnat Biplosis botularia. The insect having laid its eggs in the chan- nelled depressions above the leaf-veins, fleshy cushions arise on either side of the groove which meet above and roof them over. The cushions of tissue forming the roof do not fuse; their succulent edges merely meet, and when the time comes for the gall-gnats to leave their temporary abode the tissue dries up and shrivels,. Galls. .eoTion of one galls. V c!ZrJn'onTellortZlt^eiZm n' '''°''^'" **™'^- ' ^""^''^Imal s one Of these galls out through with the optr ulut t^^^ C«<*""»^*« «-*• away; x 3. The remaining figures natural size. attached, and the same with the operculum falling leaving a gaping slit as shown in fig. 362 \ The same thing happens on the leaves or rather leaf-vems of the Stinging-nettle {Urtica dioica) and of the Alder (Alnus gluUnosa), where the galls are produced by gall-gnats {Gecidomyi^ vHic<^, alni), and on the mxdnb of Elm leaves (Ulmus canupestris; see fig. 361«), where the galls are produced by a leaf-louse {Tetraneura alba). The so-called turpentine gall-apples (Carobe di Giude; see fig. 362*), which. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Kerner von Marilaun, Anton, 1831-1898; Oliver, F. W. (Francis Wall), 1864-1951; Busk, Marian (Balfour) Lady, 1861-1941; Macdonald, Mary Frances (Ewart); Kerner von Marilaun, Anton, 1831-1898. Pflanzenleben. English. New York, H. Holt and Company
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbotany, bookyear1895
