414 



HUTCHINSON'S POPULAR BOTANY 



FIG. 516. FLOWER or NETTLE 



(Urtica dioica). 

 The male or staminate flower. 



In the Pasque-flower (Anemone pulsatilla) 

 we have an instance of stamens metamorphosed 

 " lto nectar ^ es or ra ther f rudimentary sta- 

 mens, with shortened filaments, and glands 

 instead of anthers (fig. 486). In Papilionaceous 

 flowers, like the Pea and Bean, the cohering 

 fertile stamens secrete and store the nectar 

 (figs. 497-499). They form a tube around the 

 ovary, and the honey is poured into the base 

 of the tube. 



Very curious are the nectaries of the 

 well-known Petty Spurge (Euphorbia peplus), 

 so common as a garden weed throughout the kingdom (fig. 487). The 

 border of the cup-like involucre is studded with shining, crescent- 

 shaped glands, which are much resorted to by flies, beetles, and other 

 short-lipped insects, on account of the nectar with which the glands are 

 coated. They are, in fact, the nectaries ; and by their prominence and 

 accessibility they compensate for the inconspicuousness of the flowers. 

 There is a nearly allied plant to the Spurges, a species of Dalechampia, 

 which, according to Fritz Miiller, attraci-ts the insects which cross-pollinate 

 it by means of a colourless resin secreted in special glands. This resin 

 is collected by the insects (bees), and used in nest-building. In the Carrot 

 (Daucus\ Elder (Sambucus), and Ivy (Hedera) the nectary is also conspicuous, 

 lying almost on the surface of the flo.wer. 



Ovarian nectaries are found in Antirrhinum, Speedwell (Veronica}. 

 the Common Comfrey (Symphytum officinale), and other plants. In the 

 Spiked Speedwell (V. spicata, fig. 489) the fleshy base of the ovary secretes 

 the nectar, and the tube of the corolla holds it like a cup. A ring of 



long stiff hairs at the mouth of the tube 

 shelters the nectar from rain. This is also 

 the case with the Brooklime (V. becccibunga), 

 which is freely visited by insects, particularly 

 flies. The ovarian nectary of Comfrey (fig. 505) 

 is a white annular ridge, and in order to get 

 at it the insect (usually a humble-bee) has to 

 force apart the anthers, which form an inverted 

 cone near the mouth of the tubular corolla. 

 This releases the pollen, which falls upon the 

 insect, and in due course is transferred to 

 another flower. 



Other nectaries are sometimes found on 

 the foliar parts of plants, at a considerable 

 distance from the flowers. " It is always 

 pleasant," says a writer in Nature, 1893, " to 



FIG. 517. FLOWERS OF 



VALLISNERIA. 



(a) Female flower ; (t>) bud of male flower ; 

 (r) male flower open. 



