This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
Growing in exposed areas, the arctic-alpine chomophytes and chasmophytes are not characterized by large or conspicuous or brilliant flowers. But in sheltered positions the alpine flora of Switzerland at much greater altitudes, as is well known, is characterized by the wealth and beauty of the flowers. It is true that in such sheltered habitats in Scotland, upon a small scale, the same thing is to be noticed, but the hills are not blue with the flowers of Gentiana acaulis (erroneously recorded for Britain), or yellow with alpine Wood Anemones, etc. Still, the arctic types of Pinks, Stitchworts, Saxifrages, Primulas, etc., reflect in a lesser degree the grandeur of the alpine flower garden.
As a whole the flowers of the plants here enumerated are not large or conspicuous. The bulk are cross-pollinated by insect agency, but, as is inevitable with small-flowered plants, many are equally adapted to self-pollination. Some, indeed, such as Vernal Whitlow Grass and Ivy-leaved Toad-flax are specially fitted for the latter, the stigma and anthers ripening together. In the case of Cheddar Pink, Rue-leaved Saxifrage, and Orpine the anthers mature before the stigma, and in the case of Pellitory-of-the-wall, Sand Fescue, etc., the stigma is developed and receptive beforehand.
Cleistogamy occurs in the case of Ivy-leaved Toadflax. Pollination by the assistance of the wind is exemplified by such Grasses as Silky Wind Grass, Silvery Hair Grass, Flat-stalked Poa, and Sand Fescue, and by the Pellitory-of-the-wall.