This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
This is one of the prettiest of the genera of Primulaceae, and a most interesting group of alpine plants. Several of the species are annual, others are biennial, but the greater number are perennial, and all are rather difficult to keep under ordinary conditions near the sea-level. They are all strictly alpine plants, and are Lardy enough to resist successfully the severest temperature we are liable to in this climate; but a moist stagnant atmosphere they cannot endure. Abundant moisture at the roots is delighted in by all the species, provided the drainage be good and the soil open and porous; but the foliage of all the densely hairy species at least should be kept dry in winter and protected from battering rains. The soil should be open fibrous peat and loara, in about equal parts, and should be well sharpened up with gritty sand; and in the case of two or three species a little pounded limestone will be found advantageous. These species are Androsace lactea, Androsace villosa, and Androsace cylindrica.
Androsace Chamcejasme from the Alps, generally grows about 4 or 5 inches high, with weakly trailing branches, bearing a few small lanceolate leaves at the extremities; leaves and branches alike covered with long spreading silky hairs. The flowers are white, with yellow - often red - eyes, and are produced in small dense umbels about June, and continue till August.
Androsace Villosa forms small cushion-like tufts 2 or 4 inches high; the leaves are small in dense rosettes, and are covered with long shaggy hairs. The flowers in small umbels are pure white, with yellow or red tubes, and are of considerable substance. They appear in June and July. Found on the loftier mountains of Europe generally.
Androsace Lactea from the Alps, is a pretty little tufted species, with deep green ciliate leaves, and rather large showy white umbels of flowers; appearing from June till August.
Androsace Lanuginosa is rather loose, trailing, and spreading in growth, with rosettes of oval lanceolate leaves at the extremities of the branches, covered densely with silky-white close-lying hairs. The flowers in small loose umbels are large individually, pink, with a yellow eye, and appear in June and July.
Androsace Camea is not one of the best, but is one of the earliest flowering of the family. The stems are tufted, and terminate in rosettes of almost awl-shaped leaves, from which spring the pretty umbels of pink or rose-coloured flowers with yellow tubes; flowers in May and June. From the Alps and Pyrenees.
Androsace Cylindrica from the Pyrenees, is closely tufted in habit, and the small lanceolate blunt leaves are closely imbricate. The flower-stalks are simple, and rather longer than most of this section of the genus. The flowers are pure white, and appear in July and August.
Androsace Ciliata is one of the most beautiful of the group. It is also very easy to distinguish from any of the foregoing by the inflorescence being simple instead of compound. It forms dense cushions of closely imbricated ciliate foliage. The flowers are numerous, variable in colour, being pink, rose, and sometimes purplish or pale violet, and appears in June and July. From the Pyrenees.
Androsace Helvetica is densely cushioned in form, and the leaves are lanceolate and closely imbricate. The flowers are almost stalkless, and, like those of the last species, are produced singly at the terminations of the branches; they are pure white, and appear in July and August.