This section is from the book "Wayside And Woodland Blossoms", by Edward Step. Also available from Amazon: Wayside And Woodland Blossoms: A Guide To British Wild-Flowers.
With the appearance of the delicately fragrant Bindweed in our fields the season for summer flowers may be said to have fairly set in. Its grace of form and colour makes it a general favourite, but it resents being plucked, and closes its pink cups almost immediately. It has a perennial rootstock, which creeps and branches underground, taking possession of much soil, and sending up many slender twining stems clothed with spear-shaped leaves. The sepals are five in number, but the petals are entirely united to form a funnel-shaped corolla; though the five folds and lobes indicate the origin of the funnel. The flowers are honeyed, and are much frequented by long-tongued insects, which have to push against the anthers in order to reach the honey, carrying away pollen with which to fertilize another flower. Like a careful, thrifty plant the Bindweed closes in wet weather, and at night, that its honey may not be reduced in quality. It flowers from June to September.
- Convolvulaceae. The Hooded Bindweed (C sepium) is one of the most distinguished of our wild flowers, and it is almost impossible to see its large, pure white flowers ornamenting the hedge without desiring to acquire them. In general form it is like C. arvensis, but very much larger. Instead of being content to twine among low-growing herbs as that species, it climbs up the thickets to a height of 6 or 7 feet. In addition to the calyx this species has an enveloping pair of large inflated heart-shaped bracts - the "hood" of its popular name. The rootstock is thick and tuberous. Though it possesses honey it is not odorous, and appears to be, in consequence, but little visited by insects; it is, therefore, careless of the quality of its honey, and does not close its flowers in the rain, nor on moonlight nights, though it does so on dark nights. Sometimes the flowers are tinged or streaked with pink. Flowers June to August.
There is a third native species, the Seaside Convolvulus (C. soldanella), which does not twine, or but rarely. It has a long creeping rhizome, slender stems, and fleshy, kidney-shaped leaves. Its large rosy flowers are not numerous. There are two bracts, as in C. septum, but they are smaller than the unequal sepals, It may frequently be found on sandy shores, and flowers from June to August.