This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Erect or creeping herbs with leafy stems and yellow or white, rarely purple flowers. Leaves simple, alternate, opposite or whorled. Flowers solitary, racemose or paniculate, axillary or terminal. Corolla rotate; lobes spreading or erect. Stamens 5 or 6, included or exserted. Capsule 5 or 10-valved. There are about forty species, spread over the north temperate zone, less frequent in the southern hemisphere, and at great elevations in the tropics. The name is from a release from, and uaxn, strife.
1. L. vulgaris. Yellow Loosestrife. - This is an indigenous species of erect habit, about 3 feet high, usually found in damp places and on river-banks. Leaves opposite or whorled, ovate or lanceolate, acute, furnished with black glandular dots. Flowers deep yellow, in terminal panicled cymes, appearing in Summer.
2. L. Nummulario;. Creeping Jenny, Moneywort. - A prostrate creeping species with opposite rotundate cordate obtuse glabrous leaves and large solitary axillary yellow flowers having broad sepals, ciliate petals, and glandular connate filaments. This is a handsome plant, abundant in some parts of England, and often transferred to the garden. L. nemorum, the Yellow Pimpernel, is another native trailing species with ovate acute leaves, narrow acute sepals, and free glandless filaments.
3. L. thyrsiflora, syn. Naumbergia thyrsiflora. - An erect species from 1 to 3 feet high with sessile lanceolate leaves and dense axillary racemes of yellow flowers, produced in Summer. This plant has been separated from the other species on account of the presence of small scales in the throat of the corolla and the exserted stamens. It is a widely dispersed plant, occurring sparingly in various parts of Great Britain.
4. L. Ephemerum. - An erect species with linear-lanceolate glaucous leaves and terminal erect racemes of rather small white flowers with a dark eye and exserted stamens. It is a native of the South of Europe, and, like the others, Summer-flowering.
5. L. latifolia. - This is an erect species with solitary axillary yellow flowers on slender drooping peduncles. Leaves glabrous, linear or oblong-lanceolate. Petals slightly toothed. There are two forms : L. hybrida with broader foliage, and L. angus-tifdlia of more branching habit and narrow leaves. A native of North America.
Trientalis Europaea is a rare mountain plant in the North of England and in Scotland. It grows about 4 to 6 inches high, with one whorl of 5 or 6 shining obovate-lanceolate leaves, from which spring a few white flowers about 8 lines in diameter, on slender erect naked peduncles.
Coris Monspeliensis, the only species of its genus, is a dwarf branching plant having alternate linear coriaceous leaves and dense terminal spikes of lilac-blue flowers with yellow anthers. The calyx is double, and the corolla bilabiate.