File:Plants of New Zealand (1906) (14784162725).jpg

Identifier: plantsofnewzeala1906lain (find matches)
Title: Plants of New Zealand
Year: 1906 (1900s)
Authors: Laing, R. M. (Robert Malcolm), b. 1865 Blackwell, E. W. (Ellen W.)
Subjects: Plants
Publisher: Christchurch : Whitcombe and Tombs, Ltd.
Contributing Library: The LuEsther T Mertz Library, the New York Botanical Garden
Digitizing Sponsor: The LuEsther T Mertz Library, the New York Botanical Garden

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st overpoweringly sweetperfume. The labellum is 3-lobed, and stands nearly erect infront of the column. There is no nectary, but the tissue at thebase of the labellum is easily punctured, and exudes beads ofmoisture. The column is short and erect, the stigmaticsurface very concave, with the viscid rostellum projectingprominently forward above it. The anther is terminal anddeciduous, and encloses four pollinia attached in pairs to ashort stem, and resting on the rostellum. From the positionof the parts it appears to be impossible that self-pollinationcould take place. The pollinia are very coherent, and lieclosely ensconced in the anther case. For pollination byinsects, however, the parts are very simply fitted. An insect,visiting the flower, would insert its head or proboscis into thesmall square aperture between the labellum and the column,and in withdrawing it would inevitably touch the viscid surfaceof the rostellum, and bring away the pollinia. AVere these to THE ORCHID FAMILY 117
Text Appearing After Image:
Fig. 31. Eaiina suaveolens (nat. size) 118 PLANTS OF NEW ZEALAND be withdrawn just as they he on the summit of the cohimn,they would liardly be in a position to strike the stigmaticsurface of another flower in the hollow below the rostellum,but in being withdrawn, the cap of the anther pulls themslightly downward and depresses them considerably, so thatthey are easily placed on the stigma of a second flower. Pollination in the genus Pterostylis has been well describedby Mr. T. F. Cheeseman. The lip is sensitive, and, whentouched, closes up against the column. An insect landing uponit is thus entrapped, and the only means by which it can escapeis by the narrow channel left between the column and the lip.In passing along this channel, it must strike first the viscidstigma below the rostellum, and afterwards the anthers abovethe rostellum. The back of the insect will now besticky, so that it will carry off with it the pollinia, or portionsof them, to the next flower which it visits, and

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