. Handbook of flower pollination : based upon Hermann Mu?ller's work 'The fertilisation of flowers by insects' . Fertilization of plants. CUCURBITACEAE 455 as pollinators; in the case of Benincasa cerifera, a humble-bee was also observed. Lagenaria appears to be visited by crepuscular insects (presumably hawk-moths). The nectaries consist of a layer of secretory tissue about i mm. thick, and are provided with water-stomata. The nectar results from the conversion of starch into sugar (glucose) by means of the protoplasm or a special ferment (SoUa, Justs bot. jahresber., Leipzig, xxi (189-5), 18
. Handbook of flower pollination : based upon Hermann Mu?ller's work 'The fertilisation of flowers by insects' . Fertilization of plants. CUCURBITACEAE 455 as pollinators; in the case of Benincasa cerifera, a humble-bee was also observed. Lagenaria appears to be visited by crepuscular insects (presumably hawk-moths). The nectaries consist of a layer of secretory tissue about i mm. thick, and are provided with water-stomata. The nectar results from the conversion of starch into sugar (glucose) by means of the protoplasm or a special ferment (SoUa, Justs bot. jahresber., Leipzig, xxi (189-5), 1896, p. 335). ^^Q 312. Bryonia L. Flowers monoecious or dioecious, greenish-yellow in colour; with concealed nectar, secreted as above described. Two pairs of filaments are fused, the fifth is free. 1079. B. dioica Jacq. (Herm. Miiller, ' Fertilisation,' pp. 268-70, ' Weit. Beob.,' II, p. 210; Ludwig, Verh. bot. Ver., Berlin, , 1885, p. 21 ; Schmiede- knecht, ' Apidae europ.,' I, p. 665 ; Knuth, ' Bloemenbiol. Bijdragen.')—The female flowers of this species are only half as large as the male ones. In the latter, according to Hermann Miiller, the filaments spring from the edge of the cup formed by the fusion of the bases of calyx and corolla, and they incline together so as completely to cover the cup. Three narrow lateral passages covered by long hairs lead between the filaments to this nectary, and there is a fourth access from above, running down between the upper ends of the filaments. The anthers dehisce by long narrow clefts, curved in such a way that for most of their length they are turned towards the lateral passages, while their uppermost parts face directly upwards. An insect probing for nectar will therefore be dusted with pollen either on the lower side of its body, or on both sides of its head, and in subsequent visits to female flowers will eff"ect poUination. The female flowers are only half the size of the male ones, and are therefore usually visited
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