. Text-book of botany, morphological and physiological. Botany. INFLUENCE OF THE ORIGIN OF THE CELLS ON FERTILISATION. 913 collects below and behind the stigma among the hairs of the channel. An insect which has already brought pollen on its proboscis from another flower inserts its pro- boscis beneath the stigma through the channel into the nectary. The foreign pollen, which is attached to the proboscis, is thus rubbed off on to the lip of the stigma, it is de- tained by the viscid secretion which fills up the hollow of the latter, and subsequently emits its pollen-tubes through the canal of
. Text-book of botany, morphological and physiological. Botany. INFLUENCE OF THE ORIGIN OF THE CELLS ON FERTILISATION. 913 collects below and behind the stigma among the hairs of the channel. An insect which has already brought pollen on its proboscis from another flower inserts its pro- boscis beneath the stigma through the channel into the nectary. The foreign pollen, which is attached to the proboscis, is thus rubbed off on to the lip of the stigma, it is de- tained by the viscid secretion which fills up the hollow of the latter, and subsequently emits its pollen-tubes through the canal of the style. While the insect is sucking the nectar in the spur, the pollen of this flower, which lies in the channel behind the stigma, becomes attached to the proboscis; when the proboscis is again drawn out, this pollen does not come into contact with the viscid stigma, the lip being drawn forward by the motion of the proboscis, and the orifice of the stigma protected. The pollen that is removed from this flower is now carried, in the manner described, to the stigma of another flower. If the insect were to insert its proboscis again into the nectary of the same flower, the pollen would be detached into the cavity of its own. FIG. 492.—Epipactis latifolia: A longitudinal section through a flower-bud; B open flower after removal of the perianth with the exception of the labellum I; C the reproductive organs after removal of the perianth seen from below and in front; D as B, the point of a lead-pencil b inserted after the manner of the proboscis of an insect; E and F the lead-pencil with the pollinia attached; fKovary, / labellum, its bag-like depression serving as a nectary, n the broad stigma, en the connective of the single fertile anther, p pollinia, h the rostellum, xx the two lateral gland-like staminodes, * place where the labellum has been cut off, s the gynostemium. stigma; but, as Hildebrand has remarked, insects do not usually do this, but suck up the nectar only onc
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1882
