616 



THE GARDENER'S ASSISTANT. 



successful grower of these plants, however, is 

 he who affords them every attention, never 

 allowing them to shrivel or to be checked in 

 growth for want of water, or to suffer in other 

 ways. In a wild state the conditions during 

 the short period when they can make new 

 growth, and lay in a fresh store of moisture 

 to enable them to withstand drought, are very 

 different from anything we can provide. The 

 rains are accompanied by extreme warmth and 

 very bright sunshine. Their leaf and stem 

 structure is modified to enable them to bear 

 these extreme conditions, and to make the 

 most of them. The conditions we can supply 

 artificially are less extreme, and the growth 

 made by the plants is correspondingly slower. 

 Generally it is best to keep them growing 

 throughout the summer by supplying conditions 

 favourable to growth, and to rest them more 

 or less for a few weeks in winter. Further 

 directions for their cultivation are given with 

 each genus. 



Cacti. — These form a natural order of 

 thirteen genera and something like a thousand 

 species, all, with one or two exceptions, natives 

 of the New World, though some are now na- 

 turalized in some parts of the Old. They are 

 most abundant in Mexico and in some parts of 

 South America. They present considerable 

 variety of form and stature, some forming 

 columns 50 feet high, whilst others are small 

 cushion-like tufts. Many of them are attractive 

 on account of the strange fantastic shape of 

 their stems, their spines, and more especially 

 their generally large handsome flowers, often 

 richly coloured and deliriously flagrant. Those 

 species which expand their large flowers only 

 at night are particularly interesting. As a 

 rule they are easily kept in health, an ordinary 

 greenhouse affording conditions suitable for 

 many of them, if the light and air are good. 

 In damp, dull weather they are apt to lose their 

 roots and even the base of the stem, but they 

 strike root again readily if all the decayed 

 portions are removed and the healthy remainder 

 be placed on dry soil until it has callused and 

 started to root, when water may be given. 

 They grow well when planted in a shallow bed 

 of light loamy soil in a sunny frame or low 

 house. The best position for them would be a 

 rockery under glass facing south, and with 

 sufficient hot-water pipes to ensure a tempera- 

 ture of 50° during cold weather. 



Some species are sufficiently hardy to live 

 permanently out-of-doors in the warmer parts 

 of the British Isles. They require a sunny 



sheltered position, and should be planted in a 

 mixture of brick -rubble and loam on a well- 

 drained subsoil. A rockery against a south 

 wall is an ideal position for them, and if a few 

 lights can be fixed over them, to keep off ex- 

 cessive moisture in winter, they are much safer. 



Fig. 744.— Group of Mexican Cacti. 



The collection of hardy Cacti at Kew is 

 planted in the recesses formed by the buttresses 

 of the Palm-house, where large groups of the 

 following are grown on the south-west side of 

 the house. The border is raised by means of 

 loam and pieces of sandstone, over which the 

 plants in most cases have formed a thick inter- 

 lacing growth, having been planted there now 

 over four years. In severe weather a garden 

 mat is thrown over them. So far as tempera- 

 ture is concerned, it is never so cold in any 

 part of England as in the haunts of these 

 plants in the Rocky Mountains of Colorado, 

 &c, where 40° to 50° of frost are not unusual, 

 and at a time when the plants are bare of snow. 

 Probably the alternations of cold and wet, frosty 

 and muggy weather experienced in our climate 

 prove fatal to these plants. A sunny unheated 

 frame, with detachable lights, would be the best 

 of all situations for them. 



The following are hardy : — Cereus Engelmanni, 

 C. Fendleri, C. gonacantlms, C. Phoeniceus, C. viridi- 

 florus, Echinocatius glaucus, E. Pentlandi, E. Simp- 

 soni, Mamillaria missouriensis, M. Nuttallii, M. 

 Purpusi, M. Spcethiana, M. vivipara, Opuntia hi- 



