English
1973
ISBN: 0950050733
PDF
pages: 114
Of all the sub-families of the Cactaceae, the Opuntioideae have the greatest range in terms of latitude, the natural habitat stretching from Canada to Pata-gonia. They have escaped successfully after human introduction and established themselves wild in Southern Europe, Africa, India and Australasia. They survive in conditions quite remote from those gener-ally accepted as characteristic for the family as a whole. In a Russian newspaper in March 1969, a writer noted that some flowered and fruited after wintering under snow, with a minimum temperature down to minus 22 centigrade. Survival of intense heat and prolonged aridity is recorded from many coun-tries. Everybody knows the prickly pear, and the genus Opuntia is probably the most fully documented of all the genera of cacti, and not only from the botanic point of view. It appears, for example, in plate one of Hogarth’s Analysis of Beauty, 1753. Having been a decisive factor in at least one North American battle, having very nearly at one stage ruined the development of major tracts of Australia, the Opuntia has its place in history, quite apart from its own somewhat chequered career as an economic plant in the Canary Islands and elsewhere. Yet despite this, virtually nothing appears to have been written until well into the 19th century about a whole distinctive range of these plants stretching right down from the Western side of the Andes in Peru and across to the Eastern side and down as far as Patagonia, a matter of some 4,000 miles. The explanation is, first, that the high tablelands which they particularly favour were largely unexplored and, second, that, when they were, other and more spec-tacular phenomena seemed more worthy of attention. Even when plant hunters began to cover the vast and often difficult terrain in more detail, they concen-trated on other and more superficially interesting prizes. The splendid Flora Chilena (Vol. 3, 1847) has only ovata, longispina, glomerata, poeppigii, maihuen, ovallei, andicola, platyacantha and tuberosa of the plants that are within our field or stand near to it.
To this day, there are a number of likely areas not visited by any field botanists or others with sufficient xperience to identify possibly new plants which grow in low mounds generally, and very close to their rocky soil. So one can say with confidence that the tally of the Tephrocacti cannot yet be counted. This may also be true of the very small flat-padded Opuntiae (Airampoae) which exist over a significant part of the same range and are equally low growing. These are dwarf relatives of the big bushy prickly pears, and similarly the Tephrocacti may be envisaged loosely as among the miniature relatives of the tree-like or bushy cylindrical Opuntiae: but a statement of this crudity does no justice to the astonishing variability of the forms and sizes in which Opuntiae grow. It is also important to realize at an early stage that small races of Opuntia have evolved differently in widely separated regions. We are concerned in this book with a geographically linked range of plants and must turn away from the many fascinating, in-deed superbly spined species of North America such as clavata and schottii which differ so much in their organisation and spination and the consistently clavate rather than ovoid shape of their segments, growing generally in a step-like formation so as to form a looser mat rather than a compacted clump. They cannot (questions of geography apart) be treated as Tephrocacti without robbing the term of any meaningful status.
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