. Handbook of flower pollination : based upon Hermann Mu?ller's work 'The fertilisation of flowers by insects' . Fertilization of plants. 76 ANGIOSPERMAE—DICOTYLEDONES when present. The. latter may be double, simple, or appear merely in the form of transverse ridges. (Bunias, Ochthodium, Myagrum, Isatis, Peltaria, Neslea, Camelina.) IV. Brassiceae. Both lower and upper nectaries are present, and are never united. The lower arc prismatic, flat at the top, and inserted at the posterior side of the short stamens. The upper are always simple, either angular and columnar, or irregularly three- side
. Handbook of flower pollination : based upon Hermann Mu?ller's work 'The fertilisation of flowers by insects' . Fertilization of plants. 76 ANGIOSPERMAE—DICOTYLEDONES when present. The. latter may be double, simple, or appear merely in the form of transverse ridges. (Bunias, Ochthodium, Myagrum, Isatis, Peltaria, Neslea, Camelina.) IV. Brassiceae. Both lower and upper nectaries are present, and are never united. The lower arc prismatic, flat at the top, and inserted at the posterior side of the short stamens. The upper are always simple, either angular and columnar, or irregularly three- sided, and never in the form of a transverse ridge. (Succowia, Erucastrum, Eruca, Diplotaxis, Brassica, Melanosinapis, Sinapis, Moricandia, Rapistrum, Raphanus, Crambe.) (Cf. the abstracts given by Polak in the Bot. Centralbl., Cassel, xii, 1882, pp. 264-6, and xix, 1884, pp. 9-11.) The position of the nectaries relatively to the anthers is such that insects probing for nectar must come into contact with all or at least some of the latter with one side of their body, and touch the sUgma with the other side. The more unfavourable the position of stamens and pistil for this purpose, the more is automatic self-pollination furthered. As regards concealment of nectar, most Cruciferae belong. Fig. 26. Nectaries of some Cruciferae (after Prantl). Seen rom the side, after removal of sepals, petals, and stamens. A. Hesperis Matronalis L, B. Selenia aurea Nutt. C. Sisymbrium strictis- simum L. Brassica Napus L. to the flower class EC, a few with vertical sepals (Sinapis, Erucastrum) to E, and others, especially those with violet, red, or blue flowers (species of Matthiola, Cakile, Cardamine) to C. The last are visited by decidedly more numerous and more highly specialized insects, adapted to effect pollination, than is the case with the white or yellow flowers of Cruciferae belonging to the class EC. While these are visited chiefly by flies (especially Syrphidae), by the less specialized b
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