File:Plant-life, with 74 full-page illus., 24 being from photos, by the author and 50 in colour from drawings (1915) (14778683731).jpg

Identifier: cu31924000414908 (find matches)
Title: Plant-life, with 74 full-page illus., 24 being from photos, by the author and 50 in colour from drawings
Year: 1915 (1910s)
Authors: Hall, Charles Albert, 1872-
Subjects: Botany
Publisher: London, A. & C. Black
Contributing Library: Cornell University Library
Digitizing Sponsor: MSN

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Text Appearing Before Image:
pollination of the Common Ling, or Heather(Calluna vulgaris, Plate LXIIL), is worthy of remark.When its flowers first open they are freely visited byinsects, which in sipping honey become dusted withpollen; this they carry to the stigmas of other flowers.At this period there is no possibility of other than insectpollination. But later, when nectar is exhausted, theinsects are not attracted. Then the filaments of thestamens elongate, pushing the anthers outwards fromthe corolla, so that they may be exposed to the wind.The wind is now used as a pollinating agent, carrying thepollen to the stigmas of younger flowers. Thus, theHeather makes assurance doubly sure; it supplementsentomophilly with anemophilly. The Toothwort(Plate LIII.) adopts a similar practice. The subject of the fertilization of Orchids has beenrendered classic by the work of Charles Darwin, to whosevolume in relation thereto the reader is referred for afull discussion. An indication of the highly specialized Plate LXIII.
Text Appearing After Image:
A. CROSS-LEAVED HEATH (Erica tctralix). B. FIME-LKAVED HEATH (Erica .lucna).C LING (Cailuna vulgaris). 1. Un<ler-:.i:ic leaf 5. Flower, in section 2. Sepal G. Flown, showing four bracts 3. Flower 7. Section, Rower 4. Stamen INSECT POLLINATION 321 nature of these flowers will be found in the study of theEarly Purple Orchis (Orchis mascula, Plate LXIV.) • Theflowers are arranged in a spike, each one being attachedto the stalk by the base of its twisted ovary, and havinga long spur in which honey is secreted. One petal,which is three-lobed, forms a landing-stage for insects,while the remaining two petals form a hood protectinga pair of pollen-sacs, which do not appear conspicuouslylike ordinary stamens. At the point of attachment ofthe perianth to the ovary there is a stigmatic surface.If we push a pencil-point foremost into the mouth of aflower which has not already been visited by an insect,the pencil will come into contact with an adhesive discat the base of the pollen-sacs, and

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