Chamaecereus

Echinocereus

One of the most frequently grown cacti in this country is Chamaecereus silveslrii-, yet it is also one of those most frequently grown badly. This is a great pity since when grown well the plant flowers freely and is extremely tolerant of neglect, doing well on a bright south-facing windowsill. It is a native of Western Argentina and forms a dense matted clump of short stumpy peanut-shaped branches up to half an inch (I cm) thick and 3 or 4 in (8 or 10 cm) long. They detach extremely easily but root readily and it is a good idea to keep some plants tendency for the centre of the clump to die off sometimes. The branches have fairly prominent low ribs, usually eight in number, and the spines are produced along the edges of these from the closely set areoles. which also have a few short hairs. The close setting of the areoles gives the plant the appearance of being well covered with the bristly spines.

It is essential to treat the plant as described in the introduction to this section if it is to reward one with flowers during May and June. These are produced from the sides of the stems, generally from the longer more pendulous stems rather than the short stumpy almost upright ones in the centre of the plant. Water given in too great a quantity or too soon before the flowers are developed will merely cause the production of more vegetative growth. There is also a curious form with yellow bodies known as C.s.luleus which has to be grown as a grafted specimen.

Echinocereus enneucanlhus is still frequently sold as Cereus enneacanihus. It is a shy llowerer in cultivation and for this reason is not recommended for those who want a showy display. It is a native of Texas and Southern Mexico and makes a more or less upright plant which quickly forms clumps round its base. For this reason it is as well to grow it in a shallow pan similar to that recommended for stapelias (page 186). The stems are quite thick, frequently up to 2 in (Sent) in diameter, and are a pale rather chlorotic-looking green. These are surrounded by seven to ten quite prominent ribs, on which the areoles are set on slightly raised wart-like protuberances which are rounded at the edges. The spines are straw like and yellowish at first, becoming white later. The Greek specific name literally means nine spines, but most cultivated specimens have anything between seven and nine radial spines and at least one. and occasionally two, central spines. As mentioned earlier it is a shy llowerer but when flowers are produced they are large and a sort of strawberry jam from the fruits which is said to be very fine.

Echinocereus filchii is one of the best flowering cacti available. The stems are very variable in habit and colour but generally branch from the base of older plants. They are surrounded by between twelve and twenty-three ribs and completely covered by a network of bristly radial spines. The flowers are very spectacular, frequently 2 in (5 cm) or more across and a vivid fluorescent pink with the green stigma in the centre that is characteristic of this genus. As good drainage is essential this species generally requires a rather more sandy soil than most other cacti. I find it is very difficult to grow a plant to any size as it is susceptible to any sort of fungal attack that is going. However, this need not be a problem if seed is saved as the plants grow very readily in this way and flowers can be produced on plants of three years of age or more with little difficulty. If using a standard cactus compost it is probably as well to add a third as much sand by volume to the original mix, or alternatively granulated polystyrene may be used if this is available. Like all cacti which make rather slight root systems it is important not to overpot as this will result in almost immediate death if the plant becomes waterlogged.

Echinocereus rigidissimus is frequently confused with E.peciinalus and to make the confusion doubly confounded the E.peciinalus of horticulture is frequently more correctly botanically referred to E. rigidissimus. It is similar to E.Jilchii, described on the opposite page, but is generally very much smaller. The stems are usually solitary and tend to be rather low. although in the native habitat they may attain a height of nearly a fool (30cm). They are mid-green in colour and have about twenty low obtuse ribs. The radial spines are produced in great profusion, up to twenty or more at each areole. and because they spread widely they appear to cover the stems of the plant completely, giving the plant its rather geometric appearance by being practically joined together at the tips which are adjacent to one another. It is not as free flowering as E.Jilchii but the flowers when they are produced are similar.

It is probable that many of the forms of E.Jilchii offered for sale are. in fact, hybrids with E. rigidissimus as it is not uncommon to find plants described as the former with the extra "ridge' formed by the touching ribs of the latter. Similarly, as mentioned above, many forms of E. peciinalus are referable to the illustrated species. The true E. peciinalus has two or three central spines, whereas the true E. rigidissimus has none.

Although E.enneacanthus is sometimes referred to as the strawberry cactus, it is more usual to hear E. saim-dyckianus called by this common name. It is not easy to get hold of plants of this species but it is worth trying hard to do so as they make excellent pot plants The stems branch readily from the base and the branches can be rooted easily: they are light green in colour and have seven fairly prominent ribs arranged at regular intervals around them. The young areoles. which are closely set together on the sides of the ribs, produce yellow felt when young but this later turns brown. The spines are a dull greyish yellow and comprise nine radials and up to three centrals. The main attraction is the orange flower: this is difficult to obtain on younger plants but since they are fast growing one does not have to wait long until the plants are large enough to flower readily. When it is produced it contrasts well with the pale

This species, because of its clump-form-ing habit and shallow rooting system, really does best in a three-quarter pot or pan. as this allows it to spread around to the maximum and enables the air to circulate round the centre of the clump encouraging the ripening of the stems to assist flowering.

ing far less freely is E. sirammeus. This has slightly thicker stems up to 2} in (6-5 cm) in diameter and is a more erect plant than the preceding species. The stems, like those of E. salm-dyckianus. are pale green in colour but with many more ribs, normally between nine and thirteen in number, surmounted by the same rounded warts which characterized E.enneacanilius. The spines, as the name suggests, arc weak, rather bristly and straw like in appearance, at first brownish in coloui but becoming white with age. The central spines are very promi nent and up to 3Jin (9 cm) long in wild specimens although seldom attaining quite this size in cultivation, and the radials number between seven and len. Cultivated specimens generally have while radial spines from the start. The flowers, which are a spectacular purple, are seldom produced on cultivated specimens unless these are quite old.

Echinocereus midiflo,

Echinopsis tubiflora

Echinocereus midiflo,

Echinopsis tubiflora

Echinocereus <continued)

Echinopsis

Echinocereus <continued)

Echinopsis

Echinocereus viridiflorus is an extremely variable species in cultivation although it is probable that much of the variation is due to hybridization rather than natural mutation, but it is, as its name suggests, characterized by its curious green flowers. In habit it is dwarf, more or less erect, and branches freely from the base to form a good clump. The stems are green and the ribs, which arc usually twelve in number, are arranged spirally round the stems. This is a distinguishing feature from the other Echinocerei described in the book. The young spines are red at first, turning yellow as they age. They number about fifteen and are very small. Wild plants have a central spine but this is only occasionally found in cultivated specimens and seldom, if ever, on grafted plants.

It is usually fairly easy to spot the young flower buds on Echinocerei as large quantities of wool are produced from the flowering areoles before the flowers actually emerge. Any unusual growths from the upper part of the stem are likely to be buds and if possible it is a good idea to withhold water until this woolliness is apparent. If no wool has materialized by the end of April, however, it is better to water the plant as prolonged drought will cause it to shrivel up

Echinopsis. Echinocactus and Echinocereus all derive their names from the Greek word echinos. meaning a hedgehog. While it is true that very many cacti give the appearance and the feel of hedgehogs 1 think the name is most appropriately ascribed to the genus Echinopsis. which not only seldom produces flowers, but when it does do so. produces them in the evening. Most species of Echinopsis will benefit from being left outside during the summer although they should not be exposed to full sunlight; the north-facing slope of a rock garden, if available, is ideal. They also require a maximum temperature of TC (45°F) during the winter if they are to flower the following summer as too much warmth or too much water will merely encourage the production of large numbers of offsets but little in the way of flowering growth. Given the correct treatment echinopsis should flower within their fourth year from seed but they are not the easiest of cacti in which to induce flowering. Echinopsis eyriesii as a true species is somewhat rare in cultivation and most of the varieties described as this are either E. multiplex or hybrids of this with E. eyriesii. The true species has eleven to twelve pronounced ribs and very small reddish-brown spines which become a darker brown with age; the areoles are tightly filled with greyish wool. It is very fast growing because of its tendency to produce vegetative rather than floriferous sideshoots. and these may easily be rooted if broken olf. The flowers, which are difficult to obtain unless the instructions above are followed, are white and fragrant.

Echinopsis tubiflora has much more prominent spines than the preceding species and these are borne on white woolly areoles on the edges of the twelve conspicuous ribs. The spines are black and can grow up to half an inch (1 cm) in length. Like E. eyriesii this has been extensively hybridized and these crossed varieties arc distinguished by the absence of the black spines, whose dark coloration has been restricted to the tips of the young spines. This species flowers fairly readily for an echinopsis and as the name suggests the flowers are more funnel shaped, hardly seeming to open properly.

Another spiny species, seemingly somewhere between E. eyriesii and E. tubiflora. is E.oxygona. which has pale rose-pink flowers. One of the most fragrant of all the Echinopsis species is E. turbinata. which has white flowers.

Ecliinopsis multiplex is an extremely prolific plant producing very numerous offsets that make its chances of flowering extremely remote. Really harsh treatment and an extended period of drought and low temperatures are required in order to induce flowering. It is one of the most commonly seen plants on cottage windowsills and tolerates total neglect and bright sunlight without demur. I have known plants go for several months in summer in full sunlight without water and without showing any ill effects.

Grown properly and induced to flower it makes a very ornamental addition to any collection since the blooms, like those of E. turbinata. mentioned on the opposite page, are strongly scented. The spherical habit of the plant is often hidden under the numerous ofl'sets which, if they are produced too copiously, will cause the main plant body to become more club shaped. It normally attains a height of 6in (15cm) but can spread to a foot (30 cm) or more in diameter by means of the numerous offsets. The stems are very pale green, giving it the permanent appearance of being hungry, but it should not be fed as it will only respond by producing more and more offsets rather than flowers. It is distinguished from most of the species so far described by having many more ribs, between twelve and fourteen on the true species. The areoles are armed with ten radial spines, yellowish in colour but tipped with a dark point, and about four much darker central spines which are bent slightly over. The flowers, when they are produced, are white.

fragrant, and borne at the end of long tubes.

Echinopsis rliodolriclta might not at first be thought to be a member of this genus as it looks far trtore like a cereus in its young stages. It is extremely variable in habit, partly as the result of hybridization, and is very reluctant to flower even on older plants. The similarity to a cereus is further accentuated by its normally unbranched habit, although older plants will develop branches from the base. It is taller than any of the previously described species, often attaining a height of more than 2 ft (6Ucm) in time, and the dark or occasionally mid-green stems are surrounded by up to thirteen straight ribs. The radial spines are curved and vary between lour and seven in number: their colour loo is extremely variable, all shades between brown and white being found. Similarly with the central spines it is hard to lay down the rule, sometimes there are none at all and sometimes they are quite long.

Lobivia is an excellent group of plants for collectors and the name is an anagram of Bolivia, their native country. Like other members of this group of cacti the flowers are produced from the sides of the plant about two-thirds of the way up the stem, and the first indication of their presence is the appearance of woolly buds in the base of the areoles. Ideally, water should only be given when these appear and have been withheld after the end of April. If no woolly buds are apparent by then it may be necessary to abandon all hope of obtaining flowers that summer.

Lobivia haageana is one of the prettiest of all lobivia species. The plant bodies are upright and cylindrical and can attain a height of 12 in (30 cm) where it grows on the frontiers between Bolivia and the Argentine. The ribs are numerous, between twenty and twenty-two in number, and are arranged spirally up the sides of the stems. The areoles have some grey wool in them and about fourteen radial spines, but the most prominent feature consists of the four long black (when young) central spines that protrude from each areole. The flowers are produced fairly freely on three-year-old plants and are pale yellow in colour, and in shape similar to an inverted bell on the end of a short tube.

Lobivia densispina is probably more correctly known as L.famalimensis densispina: however, it is so commonly sold under the former name that I have decided to include it as such. The true L.famalimensis is illustrated beside it for reference.

As its name implies it is easily recognized by the very dense covering of spines that almost completely obscures the glossy dark green plant bodies. It seldom attains any great height, even in its native habitat in Southern Bolivia. In cultivation mature specimens are normally about 4 in (10cm) tall by 2 in (S cm) in diameter and for this reason it is sensible not to overpot it as this can cause a lot of water to collect round the part of the stem which meets the soil. The cultivated specimens are very variable in their more specific characteristics such as the number of ribs and spines, and this is due to the almost inevitable hybridization that occurs between the variety and the true species.

The variety illustrated is much more lloriferous than the true species and the large yellow (lowers are produced freely on plants of only two years of age. The flowers have a satin sheen about them that gives them an almost fluorescent appearance.

Lobivia famalimensis is also sometimes referred to as L.peciinifera and differs in having many more ribs, normally twenty or more, and purplish plant bodies, rather than the darker green ones of the preceding species. As mentioned earlier, horticultural varieties provide a great diversity of form partly due to hybridization and partly due to the naturally occurring mutations of the species. It is far less densely covered in spines than the variety densispina, and the cultivated forms exhibit a very wide variety of flower colour ranging through the spectrum from red to orange and yellow to

Although there is a very rare white-flowered variety of L.famalimensis called, appropriately enough, L.f.albifiora. most of the white-flowered specimens are the result of hybridization rather than naturally occurring mutation. There are also lobivias with greenish flowers, a not unusual colour for cacti, notably L. Morogona.

Lobivia f. leucomalla resembles L.f. densispina in having a dense covering of greyish spines, but differs in its almost miniature flowers which are more like those of Pseudoiobivia aurea described on the opposite page.

Lobivia jajoiana is typical of a group of lobivias characterized by hooked spines. It is rather less floriferous than the species so far described but when it does flower the unusual colouring of the throat, which is almost black, more than makes up for this. The plant bodies are almost spherical in shape and are surrounded by about fourteen very prominent ribs. The sides of the ribs are marked with slight furrows and these raise up the areoles giving the plants a slightly luberculate appearance. The areoles themselves are filled with greyish wool and have short, unremarkable radial spines and up to three central spines, the longest of which can grow to 2 in (5 cm) in length and has a conspicuous and somewhat vicious hook at the end. On the true species the flowers are a bright crimson, but some forms occur with more wine-coloured flowers; however, they all have the magnificent dark throat referred to earlier. Yellow-flowered varieties of this species are referable to L.j.nigrosioma and there is also a variety with more rounded petals called L.j.fleischeriana.

Another species with hooked spines is L. wrighliana. This has very much more rounded ribs and is generally smaller than the species illustrated. The sj

:r the st nearly the same extent as they do in L.jajoiana : the hooked spines also tend to rise more vertically than they do in the latter species, even on the sides of the stems.

Pseudolobivia

Rebutía

Pseudolobivia

Rebutía

Pseudolobivias are very close relatives of the Lobivia genus and many of the species are frequently sold under either name. Pseudolobivia aurea is by far the most common of the varieties sold and flowers readily given the right conditions. The plant bodies are almost spherical at first but as the plant matures they tend to elongate, ultimately giving the stems a more club-shaped appearance. It is a native of Argentina where it can attain a height of 5 in (13cm) or so and the pale green stems are surrounded by up to fifteen prominent and sharply angled ribs. The radial spines vary in number between six and ten and are grey or occasionally purplish with a darker tip. Up to four central spines are produced from the areoles and on mature plants these can attain a length of an inch (25 cm), although younger plants tend to have much shorter central spines. The yellow flowers are the most rewarding feature of the plant and are plentifully produced during the early summer. A great deal of variation from the illustrated species will be observed in cultivated plants sold under this name due to the extensive hybridization that has occurred between this species and Lobivia

The pseudolobivias are botanically somewhere between Echinopsis and Lobivia; whereas the preceding species was more closely related to Lobivia the next species is more closely related to Echinopsis, and is often sold under that name.

globular or at first hemispherical plant up to 4 in (10 cm) in height with pale stems sur rounded by fifteen or more narrow ribs. The radial spines, like those of echinopsis, are weak and number ten. One or two much more stout central spines are produced and these can attain a length of I in (2-5 cm). The flowers are white and are produced at the end of very long tubular stems which sprout from the side of the plant. They open in the evening and are occasionally lightly suffused with pink.

Rebutias are without doubt the most rewarding of all cacti to grow. They are undemanding plants which flower readily, by and large, even when very young. They are very closely related to the aylosteras described earlier and may be easily raised from seed. Because of their popularity they have been extensively hybridized with one another so 'as to make practical identification of cultivated material almost impossible. I propose to divide them into two groups; the quite clearly distinguishable ones, which because they are more shy flowerers lend not to be so extensively hybridized: and the very free-flowering varieties such as Rebulia minuscula, R. marsoneri and R. vioiaciflora which have been so extensively crossed with one another as to make it very difficult to obtain the true species any longer.

Rebulia haagei has in the past been known by a great many names and is still commonly referred to by nurserymen as Medio-lobivia pygmaea, which is also extensively used as a synonym for R. pygmaea described overleaf. The confusion is made even worse by the former naming of R. pygmaea as Pseudolobivia haagei.

Rebulia haagei itself is a small species forming clumps with a thick fleshy root. The plant bodies are roughly oval in shape and the spines, which are almost transparent in colour, are rather longer than those of R. pygmaea being generally over a tenth of an inch (2-5 mm) in length. The flowers are somewhat more salmon coloured than those of R. pygmaea.

Rebutia violaciflora

Rebutía (continued)

Rebutía pygmaea is, as its name suggests, a very dwarf-growing species which is sometimes offered for sale as Mediolobivia pygmaea. The plant bodies are single when young but later form small clumps rising up from a prominent thick fleshy root. It is a native of Northern Argentina and even there it seldom exceeds 14 in (4 cm) in height with stems less than an inch (2-5 cm) in diameter. Like all Rebutía species the dark green stems do not have ribs but instead there is a succession of tubercles arranged round them in spiral rows. The spines are very small indeed in cultivated specimens, normally less than a tenth of an inch (2-5 mm) in length. They are white and number about ten and are bent close back on to the stem; there are no central spines.

flowering, as is R. kupperianu. another miniature rebutía, and the flowers are a splendid carmine-red with rounded petals.

Somewhat similar but slightly taller and with more pointed petals of a rich golden hue is R. schmiedeana. The rows of tubercles here are more prominent and the stems grow to a height of 3 in (8 cm).

Rebutía senilis is easy to distinguish on bristles which almost completely cover the plant, R. senilis is a great producer of offsets and consequently tends to be a shy flowerer. It is important for this reason to withhold water until the reddish buds appear at the base of the plant or at the bases of the branches and offsets that form round it. The plant bodies of R. senilis, although 128 globular at firsl. will become more cylin drical with age. especially as the offsets form round the base and tend to force the growth in an upwards direction. The true species has pale red flowers but such extensive inter-hybridization has occurred that it is possible to find plants with all the outward appearances of J?, senilis and orange, yellow or even white flowers. Some of these varieties have been given names but in so far as commercial use is concerned most of the different coloured forms are more probably the result of crossing with other Rebutia species. R. s. dasyplirissa has very much more enlarged tubercles.

Forms of R. senilis with seemingly yellow spines and bristles are probably hybrids with R. chrysacantha. It is fairly simple to check whether a yellow-flowered form is this latter species or merely the hybrid by saving the seed - R. chrysacantha is one of the very few forms of cacti which is self-fertile. That is to say no additional plants arc required for pollination and for viable seed to be produced.

Rebutia violaciflora. R. minuscula and R. marsoneri as has already been stated are difficult to find as true species. Most of the flowering rebutias offered for sale in the shops are the result of extensive hybridization between these three distinct species. R. marsoneri itself is the only one with yellow flowers and small greenish plant bodies. Plants lacking the silky hairs of R. senilis but producing yellow flowers are probably more closely affiliated to R. mar-

Rebutia violaciflora, as its name suggests, has curious deep purple flowers and rather

Rebutia violaciflora low plant bodies similar to those of R. marsoneri. It differs from R. minuscula in having twenty-five or more rows of spirally arranged tubercles, whereas the latter species has only about twenty. Of course there is every possible range of hybrids between them, and this range of variations extends to the number of spines. The true R. violaciflora has three to five central spines and the true R. minuscula has one. although even in the true species the spine coloration is variable. R. minuscula is probably the most free-flowering species of all and individual plants can have as many as twenty flowers open at the same time, the bright red of their petals forming a sort of circular ring of fire round the mid-green plant bodies.

Rebutias have been found growing at very high altitudes and although they may be exposed to considerable cold in the wild they are always dry. For this reason they respond better than any other cactus to a period of drought. Generally speaking the longer the period of drought to which rebutias are subjected during the cool winter months the greater the profusion of flowers. As mentioned in the introduction to this section they act as a sort of watering should not be applied to any of them until the red buds are visible round the base of the plant bodies. Early watering or warm winter temperatures will merely result in the production of large non-flowering clumps.

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