SPECIES.

P. Houlletia.n.u.s (Houllet's); Fig. 56.--Stem robust, glaucous-green; ridges about eight, broad, prominent, obscurely tubercled; spines in bundles of nine, radiating, straight, less than 1 in. long, and pale yellow. Upon the growing part of the stem, the spines are intermingled with long, white, cottony hairs, often matted together like an unkempt head; these hairs fall off as the stem matures. Flowers funnel-shaped, resembling Canterbury Bells, borne in a cl.u.s.ter on the summit of the plant; ovary short and scaly; petals joined at the base, and coloured a rosy-purple, dashed with yellow; the stamens fill the whole of the flower-tube and are white; style a little longer than the flower-tube, and bearing a ray of about a dozen stigmas. Fruit globose, as large as a plum, and coloured cherry-red. The pulp is bright, crimson, and contains a few brownish seeds. In the engraving the fruit is shown on the left, and a flower-bud on the right. This species is often known in Continental collections as P. Fosterii.

[Ill.u.s.tration: FIG. 56. PILOCEREUS HOULLETIa.n.u.s.]

P. senilis (Old-Man).--Stem attaining a height of 25 ft., with a diameter of about 1 ft.; ridges from twenty-five to thirty on plants 4 ft. high; the furrows mere slits, whilst the tufts of thin, straight spines, 1 in.

long, which crown each of the many tubercles into which the ridges are divided, give young stems a brushy appearance. About the upper portion of the stem, and especially upon the extreme top, are numerous white, wiry hairs, 6 in. or more long, and gathered sometimes into locks. To this character, the plant owes it name Old-Man Cactus; but, by a curious inversion of what obtains in the human kind, old plants are less conspicuous by their white hairs than the younger ones. Some years ago, there were three fine stems of this Cactus among the cultivated plants at Kew, the highest of which measured 18 ft. There was also, however, a fine specimen in the Oxford Botanic Gardens, with a stem 16 ft. high; and it is stated that this plant has been in cultivation in England a hundred years at least. A plant twenty-five years old is very small, and, from its slowness of growth, as well as from the reports of the inhabitants of Mexico, where this species is found wild, there is reason to believe that a stem 20 ft. high would be several hundred years old.

The flowers of P. senilis are not known in English collections, the plant being grown only for its s.h.a.ggy hairiness.

Other species are: P. chrysomallus, which has a branching habit, P.

Brunnonii (Fig. 57), P. Celsia.n.u.s, P. columna, P. tilophorus, known only in a young state, and several others, all very remarkable plants, but not known in English collections, unless, perhaps at Kew.

[Ill.u.s.tration: FIG. 57. PILOCEREUS BRuNNONII.]

CHAPTER XI.

THE GENUS MAMILLARIA.

(From mamilla, a little teat; in allusion to the tubercles.)

Something over 300 different kinds of Mamillaria are known, but only a small proportion of these may be considered as garden plants. They are characterised generally by short, symmetrically-formed stems, sometimes aggregated together and forming a dense tuft, but, as a rule, each plant has only one stem. The generic name is descriptive of the chief feature in these stems, namely, the closely-set, spirally-arranged tubercles or mamillae, which vary considerably in the different kinds, but are always present in some form or other. Some kinds have stems only 1 in. high by 2/3 in. in diameter, and the tubercles hidden from view by the star-shaped cushions of reddish or white spines. In some, the spines are erect and hair-like, giving the plant the appearance of tiny sea-urchins; another group has the princ.i.p.al spines hooked at the tip, and the points in these so sharp that if the hand comes in contact with them they hook into it and stick like fish-hooks. The purpose of these hooked spines seems doubtful; certainly, they cannot serve as any protection to the plant itself, as they are so strong that the plant must be torn up by the roots before the hooks will give way.

The spines in M. macromeris are straight, and measure 2 in. in length; in M. multiceps they are in two series, the one fine, white, and short, the other yellow and stout. The most marked section of this genus, however, is that represented by M. fissurata (Fig. 61), in which the tubercles are large, spreading horizontally, and angular, resembling most closely the foliage and habit of some of the Haworthias. No one who had not read up the botany of Mamillarias would suspect that this plant belonged to them, or even to the Cactus order at all. There is a good specimen of it in the Kew collection. When in flower the family resemblance is easily seen; but as this species does not flower freely, it will be known by its remarkable foliage-like tubercles, rather than as a flowering Cactus. And the same remark applies to many of the Mamillarias; their stems thickly beset with tubercles and spines, always regular in arrangement, and neat and attractive in appearance.

The following remarks made by Dr. Lindley when describing M. tenuis, give a good idea of the singular, yet pretty, stems of some of these plants: "Gentle reader, hast thou never seen in a display of fireworks a crowd of wheels all in motion at once, crossing and intersecting each other in every direction; and canst thou fancy those wheels arrested in their motion by some magic power--their rays retained, but their fires extinguished and their brightness gone? Then mayst thou conceive the curious beauty of this little herb--a plant so unlike all others that we would fain believe it the reanimated spirit of a race that flourished in former ages, with those hideous monsters whose bones alone remain to tell the history of their existence." It is quite true that in the cultivated Mamillarias there is nothing unsightly, or rough, or unfinished. Without foliage, their stems globose, or short cylinders, or arranged in little cushion-like tufts, and enveloped in silky spines, like tiny red stars, always looking the same, except when in flower, and never looking in the least like ordinary plants. Characters such as these ought to find many admirers. In the Succulent House at Kew, there is a long shelf upon which a great many plants of this genus may be seen. But the flowers in some of the species of Mamillaria are quite as attractive as the stems. Those of M. macromeris are 3 in. long and wide, their colour a deep rose; M. Scheerii has equally large flowers, and coloured bright yellow, as also are the flowers of M. pectinata. This last is remarkable on account of the clock-like regularity with which its flowers expand. While fresh, they open every day between eleven and twelve o'clock, and close again about one, however strong the sunlight shining upon them may be. Some of the kinds (more especially the small-flowered ones) are often prettily studded over with bright red, coral-like berries, which are the little fruits, and contain, as a rule, matured seeds capable of reproducing the parent plant.

The headquarters of the genus Mamillaria is Mexico, and the countries immediately to the north, a few being scattered over the West Indies, Bolivia, Brazil, and Chili. Many of them grow on mountains where the temperature is moderate, but where the sunlight is always intense.

Others are found on limestone or gravelly hills, among short herbage, or on gra.s.sy prairies. A small silvery-spined kind has recently been found near the snow line in Chili. M. vivipara is quite hardy in New York, as also are several other kinds, whilst we learn that by planting them out in summer, and protecting them by means of a frame from heavy rain, dews, fogs, and sudden changes of weather, a good many species of both Mamillaria and Echinocactus are successfully managed in the neighbourhood of that town.

Cultivation.--Particulars with respect to cultivation are given along with the descriptions of most of the species, but a few general principles may here be noted. With only a few exceptions, all the cultivated Mamillarias may be grown in a warm, sunny greenhouse, or they may be placed in a frame with a south aspect, during our summer, removing them into artificially heated quarters for the winter. They do not like a large body of soil about their roots, but always thrive best when in comparatively small pots. If a sweet, new, fibry loam, mixed with broken bricks or cinders, be used to pot these plants in, they may then be left undisturbed at the root for several years. Much harm is often done to the more delicate kinds of Cactuses by repotting them annually; the best-managed collection I have seen had not been repotted for four years. This would not be safe if a poor and exhausted soil were used in the first instance. The pots should be well drained with crocks, and these covered with a layer of fibre sifted from loam. In summer, the soil should be kept moist, but never saturated; and after a bright warm day, the stems may be moistened over by syringing them with tepid water.

A point of much importance in connection with these, and indeed all tropical and extra-tropical plants, is, that the water used for watering or syringing them should be rain-water if possible, and never more than a degree or so colder than the plants themselves would be. Thus, a plant which had been standing in the full glare of a midsummer sun all day, would be much endangered by watering it with cold tap-water. Where proper arrangements for water are not made in a greenhouse or stove, it is a good plan to place the water wanted for the day's use in the sun along with the plants. A little bag filled with soot and tightly tied at the neck, and water, is a good method for rendering hard tap-water suitable for watering the roots of plants. In winter, Mamillarias may be kept quite dry at the roots, except in mild sunny weather, when a little water may be given.

A collection of the most distinct kinds may be successfully managed in a gla.s.s case in a room window, providing the sun shines through it for a few hours in the day.

Propagation.--This is usually effected by means of seeds, which may be procured from Continental seedsmen as well as from our own. The treatment required by the seeds is similar to what has been already advised for those of other Cactuses. The tufted kinds are easily multiplied by separating the stems, or even by cutting off the tops and planting them in small pots of sandy soil.

SPECIES. The following kinds are selected from those known to be in cultivation; of course, it is out of the question here to enumerate all the species known.

M. angularis (angular-tubercled).--A robust kind, with stems 4 in. to 8 in. high, and branching somewhat freely; tubercles prism-shaped, rather thick at the base, and slightly angular, in. long, their tops tufted with short white spines; at the base of the tubercles are little tufts of white wool. Flowers are only rarely produced by cultivated plants; they are small, tubular, rosy-purple, the stamens yellow. Introduced from Mexico in 1835; flowers in summer. When happily situated, it forms a specimen 1 ft. in diameter, owing to its freely produced arm-like branches, which spread out and curve upwards. It requires a warm greenhouse temperature during winter, and exposure to bright sunshine at all times.

M. applanata (flattened).--In this, the stem is broader than high, and has a squat appearance; tubercles in. long, cone-shaped, with stellate tufts of straight, hair-like spines, white when young, yellowish when aged. Flowers springing from the outside of the stem-top, white, tinged with red. It is a native of Mexico, and blossoms in summer. A specimen, 6 in. through at the base, may be seen at Kew, where it has been for many years, without altering perceptibly in size. All the larger-stemmed Mamillarias are exceedingly slow growers after they have reached a certain size, although, in the seedling stage, they grow freely. The treatment for this kind should resemble that advised for the last.

M. atrata (blackened).--Stem oval in shape, broad at the base, 4 in.

high, unbranched; tubercles swollen, in. long, deep green, cone-shaped, becoming flattened through pressure of growth. Spines set in a tuft of white hairs, falling off from the lowest mammae, as happens in many of the thick-stemmed kinds. Flowers numerous, and developed all round the outside of the stem, stalkless, nestling closely between the tubercles, and when expanded looking like starry b.u.t.tons of a rosy-pink colour.

Native of Chili, flowering in autumn. This species is rare in England, but is worth attention because of the prettiness of its flowers, the attractive form of its stem, and its reputed hardiness. It will thrive in a cold frame, and requires protection from excessive wet only, rather than from cold. Grown in a warm house, it becomes sickly, and is short-lived.

M. bicolor (two-coloured).--One of the commonest of the Cactuses grown in English gardens, and one of the most distinct, owing to its short, silvery hair-like spines, thickly crowded on the ends of the small tubercles, completely hiding the stem from view. The latter is from 6 in.

to 1 ft. high, 3 in. in diameter, cylindrical, often branching into several thick arms, when it has a quaint appearance. If kept free from dust, which may be done by covering the plant with a bell gla.s.s, there is much beauty in the stem; indeed, it is owing to this, rather than as a flowering Cactus, that this species finds favour as a garden plant.

The flowers are less than 1 in. in length and width, stellate, their colour deep purple; they are developed in June. Although a native of elevated regions in Mexico (4000-5000 ft.), this plant thrives best when grown in a warm house. There are several handsome and very old specimens of it in the tropical collection of succulents at Kew. It is one of the easiest to manage, and will thrive in a warm room-window if exposed to bright sunlight and kept dry in winter. M. nivea and M. n.o.bilis are both varieties of this species.

M. chlorantha (greenish-yellow).--A newly-introduced species with erect, cylinder-shaped stems, 6 in. high, clothed with numerous tubercles, which are tipped with cl.u.s.ters of long, silvery, interlacing, hair-like spines, and a few stouter blackish ones. The flowers are described as greenish-yellow, so that they are not likely to add much to the beauty of the plant, which is recommended because of the attractiveness of its stem and spines. It is a native of Mexico and Texas, whence it was introduced some two years ago. It requires cool-house treatment, and should be kept free from dust, which disfigures the white spines.

M. cirrhifera (twisted).--Like M. bicolor, this species owes its frequent occurrence in gardens to the symmetry and neatly-chiselled form of its stems, and not to any attraction possessed by its flowers. It will thrive anywhere where the sun can shine upon it, if sheltered from severe cold and wet. In a cottage window it may be grown, and kept for many years, without losing health or, on the other hand, increasing much in size. Its usual height is about 5 in., by 4 in. in diameter. The tubercles are angular at the base, and bear tufts of yellowish spines on their pointed apices. The flowers are small, and bright rose-coloured, but only rarely produced on cultivated plants. Introduced from Mexico in 1835.

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 1 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 cl.u.s.tered, in a kind of disk, through the middle of which the yellow stigma projects. It is a native of Mexico, at an alt.i.tude 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 gra.s.s 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 cl.u.s.ter 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, 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.

[Ill.u.s.tration: FIG. 58. MAMILLARIA DOLICHOCENTRA.]

M. echinata (hedgehog-like).--A charming little plant, with very small stems, cl.u.s.tered 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 cl.u.s.ters 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 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.

[Ill.u.s.tration: FIG. 59. MAMILLARIA ECHINUS.]

M. elegans (elegant).--A small species, grown only for the prettiness of its stem, flowers rarely, if ever, being borne by it under cultivation. The stem is 2 in. high and wide, globose, with small conical tubercles, which, when young, are woolly at the tips. Spines short and slender, about twenty, arranged in a star on each tubercle, with four central ones a little longer than those which surround them; the colour of the spines is whitish, with brown tips. Native country Mexico, on high exposed hills; in this country it requires greenhouse treatment.

Introduced about 1850.

M. elephantidens (elephant's-tooth); Fig. 60.--One of the largest and most remarkable of all garden Mamillarias. Stem globose, depressed, 6 in.

to 8 in. in diameter, and bright shining green. Tubercles smooth, round, 1 in. long, furrowed across the top, which is at first filled with wool, but when old is naked. At the base of the tubercles there is a dense tuft of white wool, and springing from the furrows are eight radiating recurved spines, and three short central ones, all strong, stiff, and ivory-white, tipped with brown. The flowers are 3 in. wide, and are composed of a circle of violet-coloured sepals, with white margins, and a second circle of petals which are bright rose, pale purple at the base, a line of the same colour extending all down the middle. The stamens are numerous, with long purple filaments and yellow anthers, and the pistil is stout, erect, projecting above the stamens, with a radiating stigma. Flowers in autumn; native country, Paraguay. Under cultivation, it grows quicker than is usual with plants of this genus, and it is also exceptional in the regular and abundant production of its flowers. It has been a rarity in European collections for many years, and, although easily grown, it is often killed through wrong treatment.

A cool greenhouse or sunny frame in summer, plenty of water whilst growth is active, and a light, well-drained soil, suit it best; whilst during winter it must be kept perfectly dry, and protected only from frost. In a tropical house, it is invariably sickly, and altogether unsatisfactory.

[Ill.u.s.tration: FIG. 60. MAMILLARIA ELIPHANTIDENS.]

M. elongata (elongated).--A small, cushion-like kind, with the stems in tufts, owing to their producing offsets freely from the base, the tallest of them being about as high and as thick as a man's thumb. The tubercles are short, crowded, and hidden under the star-cl.u.s.ters of reddish-yellow spines. There are no central spines in this kind. The flowers are produced in the axils of the tubercles from all parts of the stem, a large tuft of stems being thickly studded with circles of tawny yellow petals, which are only about in. long. The berries are bright coral-red, and about the size of a date stone. There are several varieties of this species, under the names of intertexta, rufescens, rutila, subcrocea, and supertexta. These differ only slightly either in the length or thickness of the stems or in the colour of the spines. All of them may be grown in a cold frame, or in a window where the sun can shine upon them; or they may be grown along with tropical kinds. For small cases in windows, these little Thimble Cactuses are amongst the most suitable. They are natives of high mountains in Mexico, and have been cultivated in Europe over forty years.

M. fissurata (fissured); Fig. 61.--In appearance, this rare species mimics some of the Gasterias, and is so different from all the kinds. .h.i.therto described, that very few people unacquainted with it would suspect that it belonged to the same genus as M. elongata or M.

dolichocentra. Indeed, some botanists have made a separate genus of this and several other plants of the same peculiar appearance, calling them Anhalonium. M. fissurata is like a whip-top in shape, the root being thick and woody, and the tubercles arranged in a thick layer, spreading from the centre, rosette-like. A living plant in the Kew collection is 2 in. high by 4 in. wide, the tubercles being triangular in shape, in.

thick, wrinkled, with an irregular furrow on the upper surface. The flowers grow from the middle of the stem, and are 1 in. wide, and rose-coloured. Native of Mexico, on hard gravel or limestone soils. We know of no plant in English collections, except that at Kew, which was introduced from Mexico in 1886. It flowers in September and October.

[Ill.u.s.tration: FIG. 61. MAMILLARIA FISSURATA.]

M. floribunda (free-flowering).--A French writer on Cactuses, M.

Labouret, calls this a species of Echinocactus, but it resembles so closely another species included by him in Mamillaria, viz., M. atrata, that we see no good reason for separating the two into different genera.

M. floribunda has an irregular conical stem, about 5 in. high by 4 in.

wide at the base, round nut-like tubercles the size of filberts, crowned with star-tufts of spines in. long, stiff, and brown, about ten spines being set with their bases in a small disc-like pad of dirty-white wool.

The flowers are very numerous, covering the whole of the stem-top, from which they stand erect, so as to form a dense bouquet of rose-coloured petals. Each flower is 2 in. long. Native of Chili; introduced about 1835. Flowers in summer. This handsome kind will thrive in a window, and, if well supplied with fresh air, sunshine, and sufficient water to keep the soil moist, it will flower almost every year. It must have no water in winter.