[M. clava] (club-shaped); Bot. Mag. 4358.—In the size of its stem, and the large, brightly-coloured flowers it bears, this species may be compared with some of the Echinocactuses. The stem is from 1 ft. to 1½ ft. high, 4 in. wide at the base, narrowing slightly upwards; the tubercles are 1 in. long, and nearly as much through at the base, their shape that of little pyramids, and their tips bear each from eight to eleven stout, straight spines, pale brown, with a little wool at the base. The flowers are borne on the top of the stem, two or three of them together; the sepals are green and red, and the spreading petals are straw-coloured and glossy, their edges near the top being toothed. In the centre of the shallow cup formed by the petals, and which measures nearly 4 in. across, the orange-coloured stamens are clustered, in a kind of disk, through the middle of which the yellow stigma projects. It is a native of Mexico, at an altitude of 5000 ft. Introduced in 1848, when it flowered at Kew, in June, at which time it flowers almost every year now. A warm greenhouse affords the most suitable conditions for it; but, unless it is kept in full sunshine both summer and winter, and perfectly dry during the latter season, it will not produce any flowers. As a flowering plant, it ranks amongst the very best of the Mamillarias. It is easily propagated from seeds ripened on cultivated plants.
[M. dasyacantha] (thick-spined).—Stem 2 in. to 3 in. high, almost globular, and covered with spiral whorls of tiny tubercles, in the grooves of which is a little whitish wool, which falls away as the tubercles ripen. The spines upon the tubercles are arranged in little stars, with an erect central one. The flowers are small, and spring from the centre of the stem. This is one of the Thimble Cactuses, and is too small to have any great attractions, either in stem or flowers. It is, however, a pretty plant, especially when studded with its ruby-like flowers, which look like coloured Daisies growing upon a dense tuft of hairs. It is a native of Mexico, where it grows on high mountains among short grass and other herbage.
[M. discolor] (spines two-coloured).—Stem globose, about 4 in. in diameter; tubercles smooth, egg-shaped, their bases embedded in white wool, their tips crowned with stellate tufts of short, reddish spines. Flowers numerous, and borne from almost all parts of the stem, less than 1 in. wide, and composed of a single whorl of narrow, reflexed, rose-purple petals, surrounding a large, disk-like cluster of yellow stamens. The flowers are so short that they are half hidden by the tubercles. It is a native of Mexico, where it grows on rocks, in warm, sheltered places. Under cultivation it thrives when grown on a dry shelf in a warm house, and kept moist in summer, but perfectly dry in winter.
[M. dolichocentra] (long-spurred); Fig. 58.—Apparently this is a variable species; at all events, plants of widely different habit are found under this name, one of them represented in the Figure here, another in the Garden, Vol. XVII., whilst others are figured or described in other books. What is known at Kew as the true plant is that here figured. This has a stout stem, about 8 in. high and 3 in. wide, and covered with smooth cone-shaped mammae, with woolly bases and stellate tufts of spines on their tips. The flowers are produced about 1 in. from the top of the stem, and are less than 1 in. wide; they are, however, often very numerous, sometimes a closely-set ring of them surrounding the stem, like a daisy chain, their colour being pale purple. Below the flowers there is often a whorl of club-shaped fruits, ¾ in. long, and rose-coloured. These contain numerous little black seeds, which, when ripe, may be sown in pots of very sandy loam. The plant is a native of Mexico, and flowers in summer. It thrives in a tropical temperature, and enjoys a daily syringing overhead on bright days in summer, but in winter requires little or no water.
FIG. 58.—MAMILLARIA DOLICHOCENTRA
[M. echinata] (hedgehog-like).—A charming little plant, with very small stems, clustered together in a cushion-like tuft, each stem less than 1 in. wide; but a well-grown specimen is composed of dozens of these, packed almost one on top of the other. The tubercles are hidden by the star-like spine clusters which cap them, and look like a swarm of insects. Flowers very small, rose-coloured, and lasting only about a day. These are succeeded by numerous currant-like red berries, so numerous, in fact, that the plants look as if thickly studded all over with coral beads. The central stem is sometimes about 6 in. high, those surrounding it being shorter and shorter, till the outside ones rise only just above the soil. A well-grown plant of this is strikingly pretty, even when not in fruit. It is a native of Mexico, and requires the treatment of a warm house. A few pieces of broken brick should be placed upon the surface of the soil about the base of the plant, as the stems like to press against, or grow upon, anything in the nature of rocky ground.
[M. echinus] (hedgehog-like); Fig. 59.—A distinct and pretty little plant, the largest specimen having a stem about the size and shape of a small hen's-egg, completely hidden under the densely interwoven radial spines, which crown the thirteen spiral rows of tubercles, and are almost white when mature. The tubercles are ½ in. long, and, in addition to these white radiating spines, they also bear each a stout spike-like spine, growing from the centre of the others. This spine gives the plant an appearance quite distinct from all other cultivated Mamillarias. The flowers are produced two or three together, on the top of the stem, and they are nearly 2 in. long, cup-shaped, and coloured yellow; they usually appear about June. As yet this species is rare in cultivated collections. It comes from Mexico, where it is found growing on limestone hills, in hot and arid localities. Under cultivation it requires a warm greenhouse temperature, exposure to bright sunshine all the year round, with a moderate supply of water in summer, and none at all during winter. A few large pieces of broken brick or sandstone placed in the soil, just under the base of the stem, afford the roots conditions suitable to their healthy growth.
FIG. 59.—MAMILLARIA ECHINUS