Introduction

the importance of a hobby is increasing as people have more and more leisure time, and

hobbies connected with natural history are booming. The increase in the number of cacti

enthusiasts around the world is reflected by the number of societies which are now in existence

in almost every country from England, where this hobby started, to countries such as Russia

and Japan. Fortunately this growing interest has made people more aware of their native

flora and the need for conservation.

Another factor is that most cacti and other succulents originate in the type of environment

where the degree of atmospheric humidity is very low, so these plants are far more suited to

centrally heated homes than many of the house plants which have been grown in recent years.

Although the majority of cacti do not actually need a high minimum temperature in winter,

they will not die as a result of it, although it can adversely" affect their flowering qualities in the

following season. Ideally these plants will do best in a small greenhouse, a conservatory or a

sunroom; it is also possible to grow them very well in a cellar using artificial lighting, whilst a

variety of carefully chosen species can be grown in a raised rockery in the garden for twelve

months of the year, even though they will be subjected to snow and ice during the winter.

Many people may not realise that although cacti are only native to the Americas or the New

World a vast range of other succulent plants are to be found in almost every country in the

world including, believe it or not, such chilly parts of the world as Greenland, the alpine areas

of Switzerland and the Caucasus, and even in the Himalayas. It is true to say that by far the

majority of these succulent plants are to be found in Africa and the surrounding islands as well

as in the Americas, but there are also many species in India, Sri Lanka (Ceylon), Burma,

China, many of the islands in the Pacific Ocean and Australia.

This book illustrates one plant from each of one hundred different genera, with a page or

half page of text describing not only where the species in a certain genus occur in habitat, but

also the basic features of that genus. It should be possible to place a plant in its correct genus

(shown by the first name) with the aid of the non-technical text which accompanies each of

the illustrations.

The main problem has been the selection of the genera to be included, and we are quite

certain that someone will say, 'Why did you not include such and such a genus?' We have

included more true cacti than other succulents, but we have endeavoured to include flowering

plants, wherever this is really important for easy identification. We have also shown a selection

of genera of which certain members are suitable for use as house plants. A few genera such as

Sedums and Sempervivums, many of which can be grown outside rather like alpine plants, are

included as well as some species of hardy cacti.

The text and illustrations are arranged as far as possible in alphabetical sequence by the