We come now to a group of opuntias which are characterized by having rounded or oval stems as opposed to the flat-jointed ones discussed earlier. Here again considerable confusion exists between botanical and commercial names. Most growers, probably as a result of having long runs of printed labels in the past, sell the plants under the generic name Opuntia. Botanists seem to prefer to call them Cylaubvpunlia or, even worse, Austrocylindropuntia; thus for example Optmlia subulata is, in fact, probably the same plant as the one described in this book as Austrocylindropuntia

The name Austrocylindropuntia is given to a group of plants coming from South America, and is derived from the Latin

Austrocylindropuntia cylindrica is a slightly branched upright plant with cylindrical stems covered in wart-like tubercles from which the areoles emerge. As the trunk of the plant becomes older so these tubercles, disappear leaving it smooth. The joints are flattened at the apex, looking somewhat as though they had been hit rather too hard with a mallet, and long leaves are produced at the tips of the young shoots which fall off naturally the following winter, if not earlier. The areoles are set down quite deeply in the tubercles and are tilled with white wool, and have some long hairs hanging down from them. Although greenhouse-grown specimens are often spineless, the wild variety has two or three spines growing out of each areole. The flowers are very 106 small and inconspicuous and arc seldom seen on cultivated specimens. The plant grows at some considerable height in Ecuador and Peru, and will tolerate fairly low temperatures if the air can be kept very dry. It will not. however, tolerate a damp cold such as we normally get in Britain in the winter. This particular variety is also often sold in both cristate and monstrose forms, and the former can make a very handsome plant indeed.

Austrocylindropuntia salmiana is probably the most worthwhile of all the opuntias for the amateur. It is a delicate shrub and flowers can be induced on four-year-old specimens with no great difficulty. It comes from Brazil. Paraguay and Northern Argentina. The plants are all sterile and this means they cannot be raised from seed, but this is no great hardship as the cuttings root readily and grow quickly into fair-sized plants. Plants grown in a good soil with plenty of natural light should not need staking, but may be pruned regularly to ever, on a windowsill in a city the plant may become straggly and need staking if it is to retain its attractive appearance. The stems are normally purplish and this in itself does not indicate lack of water, but great care should be taken to prevent the plants drying out as the weak slender branches can desiccate very quickly in the summer and also in the winter if allowed to stay in too warm an environment. The flowers arc the main attraction of this species and are similar to those of a dog rose. The colour is very variable, most commonly yellow, but there is also a white variety, and some of the white ones are occasionally tinged pink.

Austrocylindropuntia subulata is another excellent species for the beginner but may be confusing since it can adopt one of two different habits. The more commonly seen type is the branching one, throwing up from the base a cluster of thick fleshy joints tipped with very long succulent leaves which, unlike other species, may persist for several years before finally falling off. The younger areoles are sometimes completely spineless but often have up to two slender weak straw-coloured spines. Later the older areoles on the trunk develop up to eight spines or more in a cluster. The branches start at right angles to the stem but as they grow they soon become upright giving the plant its traditional clump appearance. The young pads root easily. There is also a form with a simple erect stem, rather similar to A. cylindrica but lacking the long white hair. The flowers, which are very small, are orange or greenish yellow; they are rarely produced in cultivation and were for a long time unknown. The species was also for a long time thought to be a pereskia but was transferred to its correct genus in 1883 by Dr George Engelmann after whom Opuntia engelmannii. illustrated and described on page 102, was named.


Austrocylindropuntia vestita comes from Bolivia where it grows in the hills round La Paz. The roots are very fibrous and the plant is intolerant of overwatering or poor soil hygiene. The stems are very branched and weak and the plant forms small clumps in its native state. The joints of imported specimens may be quite short, but green-house-grown plants, with better soil and more fertilizer round their roots, tend to produce lusher, longer joints; however, even the greenhouse varieties retain the fragile nature of the originals and the cylindrical joints can be damaged very easily by careless handling. The areoles have short wool in them, spines, and some long hairs which give the plant a very decorative appearance. Very small leaves are also produced although these fall quite naturally once water is withdrawn in the winter. The flowers are small, produced only on well established plants, and are followed by bright red fruits. These persist for some time on the plant and subsequently produce up to five rather spiny joints each, after which they fall off and re-establish themselves as new plants on the ground. There is also a cristate form of this plant quite readily available and this makes an extremely decorative addition to a collection as well as being considerably less fragile than the true species.

Cylindropuntia leptocaulis is another species where great differences can occur in shape. As most commonly offered it is a bushy compact plant, but there are also some forms which have short, definite trunks up to 3} in (9 cm) in diameter. The stems or side branches, like those of the preceding species, are slender, but become a little thicker with age. They are easily detached from the main stem but if this happens they can be rooted with the same ease. The areoles have white wool set into them but no long hairs. The most conspicuous feature of the plant is the long, white, usually solitary spines up to 2 in (S cm) in length. These are covered in papery sheaths which can become detached as the spines mature on the plant. There is considerable diversity of appearance in the length of the spines and the character of the spine sheaths, but this may have something to do with the very wide area where the plant grows wild, ranging as it does from the Southern United States to Puebla in Mexico.

Cylindropuntia tunicata also has very conspicuous papery sheaths round its spines and like the preceding species is very variable in habit, coming from the Highlands of Mexico. Ecuador. Northern Chile and Peru. As most commonly seen in Britain it forms a prostrate much-branched clump, but forms are available in which it grows upright to some considerable size and develops numerous lateral branches. The joints are very brittle but they rarely attain their full size in cultivation: the spines, however, usually develop well. Although very ornamental the spines are vicious and great care should be taken in handling the plant. In view of its normally prostrate habit it is best grown in a seed tray or wide shallow pan as this delays the evil day on which it has to be repotted since this is not a job to be undertaken lightly. Other species with similar papery spines are C.imbricata. which differs in being far more upright in habit: C. bigelovii and C. ciribe, which are bushier plants, the former more densely armed with spines than the latter: and C.alcahes and C.fulgida, the latter with joints which are very readily detached and brownish spines, and the former having more persistent joints with white spines.

Generally this last group of plants is unsuitable for the amateur or for those with only limited space available, since although they are fairly tolerant of poor conditions the dense covering of vicious spines makes them difficult to handle, and the spreading nature of their growth makes it awkward to get at other plants in cramped conditions without hurting oneself.



The Cereanae



The Cereanae are a group of candelabra-type cacti falling within a very large subgroup of the cactus family known collectively as the Cereeae. Seventy-five per cent of all cactus species belong to the Cereeae and a great diversity of forms and flowers is mainly spine-bearing areoles. ribbed stems, and produce their flowers and spines from the same areoles. They produce several joints and are normally erect, bushy or arching, as opposed to the Hylocereanae which are more vine like and sprawl around producing aerial roots at intervals. Many of the typical branching .characteristics of the group do not appear until the plants are well established, a particularly good example being the national flower of Arizona, the saguaro. which when purchased is normally a small dumpy little plant that takes a long time to achieve any resemblance of its natural shape as it is very slow growing. As a group they flower only when they have reached a fair size; it is unusual, for example, for Cereus peruvianas to flower when less than 2 or 3 ft (60 cm or I m) tall. For potting compost use a sandy well drained loam and be sure to give them a cool dry environment in winter, generally a temperature of 6 to 8°C (43 to 46 F) is adequate, although some kinds, notably Lemaireocereus will appreciate another 3°C (5°F). As a group they are also fairly easily raised from seed, and cuttings taken by slicing off the tops of the stems root readily in most cases, as well as causing the parent plants to start branching.

Carnegiea giganlea is one of earliest recorded species of cactus and is so impressive in its natural habitat in Arizona. Southern California and Mexico that it has been adopted as the national emblem of Arizona. It is commonly known by the Indian name of saguaro but it is also sometimes referred to in the literature as pitahaya. Parts of the plant are used to make building materials and the fruit is made into a sort of broth by the Indians. It is extremely slow growing and very unlikely to flower in cultivation. Commercially available specimens have a somewhat globular appearance and the normal upright shape only begins to be apparent in plants of six years of age or eleven ribs carrying areoles about half an inch (I cm) apart supporting eleven or more radial spines and four or five central spines. All the spines are of a somewhat brownish colour but the central spines become paler as they grow older.

While Carnegiea giganlea can really only be recommended to the beginner on account of its national and historical associations. Cereus forbesii can be strongly recommended for its horticultural appeal. It is also known as C. vaiidus. is a native of Argentina and is easily raised from seed. Moreover it starts forming branches when quite young and even pot-grown plants have an attractive and typical appearance. The branches have a slight bluish sheen when young which fades quite naturally with age and each branch has four to six ribs somewhat compressed. The areoles are set in slight notches along the flattened edges of the ribs, fairly close together, and support up to five short radial spines and usually a solitary central spine (although occasionally even as many as three) which is much stouter than the radials and nearly 6}in (16cm) in length on mature specimens. It is distinguished from C.peruvianus by having fewer ribs (C. peruvianus has between six and nine in mature specimens) and from C.jamacaru by its closer areoles and red flowers. IC.jamacaru has green flowers and areoles nearly an inch (2-5 cm) apart.] Such extensive cross hybridization has occurred between all three species as plant to a particular species, especially when they arc very young, and the above guide lines are only very general. Few varieties are named correctly when bought, as the process of differentiating between them is almost impossible when the plants are young and before they have developed their full complement of ribs.

and most spectacular of all the upright cacti. Many plants offered for sale as C.peruvianas are. in fact, C.jamacuru and the difference between them is in the number of ribs. C.jamacuru has four to six ribs while C. peruvianus has six to nine, although the count should only be made on plants of three years of age or more. If you have young specimens it is probably best to label them merely as Cereus sp. until the plants are large enough to hazard an identification.

Cereus jamacaru is found native in Brazil, although it has been used extensively as a hedging plant throughout the West Indies. It is a very large plant in its native state often growing to 30 ft (9 m) in height or more and the name 'jamacaru' is supposed to be the Indian name of the plant. The trunk can be up to 2ft (60 cm) in diameter and is frequently used to make boxes and picture frames. The young shoots of the plant are also occasionally used during very dry periods to feed the cattle. The young shoots are normally quite blue although as they grow older this bloom fades naturally, just as in C.forbesii. The ribs are fairly pronounced when young and, like the preceding species, are wavy along the edges with areoles recessed into them. The spines vary greatly from plant to plant but "are yellowish in colour. The flowers are only produced on fairly large specimens and they are nocturnal and pollinated by moths.

Similar species are C.slenogonus and C. xamhocarpus. The former sometimes has glaucous-blue young shoots but the latter never does. For those who want to Uy cook ing the fruits there is quite an important distinction between the two. The fruits of C. xamhocarpus are quite tasty but those of C.slenogonus are rather unpleasant: they are yellow and reddish orange in colour respectively.

As has been already said C. peruvianus is not nearly as common in fact as the number of plants labelled as such would lead you to believe: the distinguishing feature is the greater number of ribs (up to nine and not less than six). There are two very attractive monstrose varieties of this plant known as C. p. monsirosus and C. p. monslrosus minor. The former is frequently seen in collections but is very slow growing indeed, nevertheless mature specimens make a splendid showpiece for a collection. As if to make the problem with the names more difficult C. peruvianus is not. in fact, a native of Peru at all but comes from South-eastern South America.

Cereus aeihiops and C. azureus are both similar when grown in pots. They differ from each other in the shape of their ribs, the latter having more wavy ribs than the former. They differ from C.peruvianus in their much lower habit, although they all have the magnificent bluish flock on the young growth, the latter, as its name suggests. being particularly attractive in this

EulychmaJloresii is probably more correctly called E. iquiquensis. The generic name is derived from the Greek word meaning a torch and the plant is a native of Chile. The spines of this species are particularly impressive on the young growth although they fall off as the plant ages leaving a virtually spineless trunk. They are used as lire logs in South America where they dominate the landscape in many parts. E.floresii is an upright columnar plant attaining a height of over 20 ft (6 m) in its native Chile, branches are formed near the base and the stems are dark green with ten to fifteen low broad ribs almost hidden behind the practically adjacent areoles. The areoles are full of tufts of whitish wool which hides the numerous short radial spines. The central spines are very variable but most cultivated specimens have a solitary central spine, of a rather handsome grey colour with a darker tip. up to 5 in (13 cm) or so in length on mature plants and normally over 2 in (5 cm) even on quite young plants.

Cactus Int Rieur
Building Your Own Greenhouse

Building Your Own Greenhouse

You Might Just End Up Spending More Time In Planning Your Greenhouse Than Your Home Don’t Blame Us If Your Wife Gets Mad. Don't Be A Conventional Greenhouse Dreamer! Come Out Of The Mould, Build Your Own And Let Your Greenhouse Give A Better Yield Than Any Other In Town! Discover How You Can Start Your Own Greenhouse With Healthier Plants… Anytime Of The Year!

Get My Free Ebook

Post a comment