Primulasamily: N.O. Primulaceae
The leaves of some species produce irritation to face and hands resulting sometimes in a form of eczema. This is caused by a secretion in the glandular hairs and is termed primula dermatitis. The roots of Primula grandiflora give a crystalline polyatomic alcohol, 'primulite,' said to be identical with hepatomic alcohol 'volemite.' Two glucosides, Primverin and Primulaverin, and an enzyme, primverase, have also been isolated in it.
The Primrose family is remarkable for the number of hybrids it produces. The garden 'Polyanthus of unnumbered dyes,' as the poet Thomson calls it in 'The Seasons,' is only another form (probably of the Cowslip or Oxlip) produced by cultivation, and is one of the most favourite plants in cottage gardens, of endless variety and easy cultivation. The Oxlip is distinguished from the Primrose by its flowers being stalked umbels and of a deeper shade of yellow and by its leaves becoming suddenly broader above the middle. It varies from the Cowslip by its tubular, not bell-shaped calyx and flat, not concave corolla.
All the hardy varieties of Primula, whether Primrose, Cowslip, Polyanthus or Auricula, may be easily propagated by dividing the roots of old plants in autumn. New varieties are raised from seed, which should be sown as soon as ripe, in leaf-mould, and pricked out into beds when large enough.
Among the many splendid flowers that are grown in our greenhouses none shows more improvement under the fostering hand of the British florist than the Chinese Prirnula, which originally had small, inconspicuous flowers, but now bears trusses of magnificent blooms ranging from the purest white to the richest scarlet and crimson. The Star Primulas which have attained an even greater popularity in late years are considered perhaps even more elegant, being looser in growth and carrying their plentiful blossoms in more graceful, if not more beautiful trusses. Both varieties are among the most beautiful of our winter-flowering plants, the toothed and lobed, somewhat heartshaped leaves being extremely handsome with their crimson tints.
Seeds of these greenhouse Primulas should be sown in the spring in gentle heat, the soil used being very fine and pleasantly moist. The seedlings must be pricked off and potted on as necessary, with a view to ensuring sturdy, healthy growth.
P. obconica is a slightly varying type of these greenhouse Primulas, the leaves approaching more the shape of those of the common Primrose; the plants are exceedingly floriferous and graceful, the full trusses of delicate lilac flowers are borne on tall slender stems and care must be used in the handling of it, as the leaves sometimes cause an eruption like eczema. Homoeopaths make a tincture from this species.
The broad, thick leaves of the Auricula (P. auricula), a frequent garden plant in this country, though not native to Great Britain, are used in the Alps as a remedy for coughs.