“ The brilliant colour of the flowers, often occurring in large numbers (as in the alpine gentians) , the presence of honey-glands and the frequency of dimorphy and dichogamy, are adaptations for pollination by insect visitors. In the true gentians (Gentiana) the flowers of different species are adapted for widely differing types of insect visitors. Thus Gentiana lutea, with a rotate yellow corolla and freely exposed honey, is adapted to short-tongued insect visitors; G. Pneumonanthe, with a long-tubed, bright blue corolla, is visited by bumble bees ”

“ The corolla shows great variety in form; thus among the British genera it is rotate in Chlora, funnel-shaped in Erythraea, and cylindrical, bell-shaped, funnel-shaped or salver-shaped in Gentiana; the segments are generally twisted to the right in the bud; the throat is often fimbriate or bears scales. The stamens, as many as, and alternating with, the corolla-segments, are inserted at very different heights on the corolla-tube ”

“ The leaves are in decussating pairs (that is, each pair is in a plane at right angles to the previous or succeeding pair) , except in Menyanthes and a few allied aquatic or marsh genera, where they are alternate or radical. Several genera, chiefly American, are saprophytes, forming slender low-growing herbs, containing little or no chlorophyll and with leaves reduced to scales; such are Voyria and Leiphaimos, mainly tropical American. The inflorescence is generally cymose, often dichasial, recalling that of Caryophyllaceae, the lateral branches often becoming monochasial ”