SELECT SPECIES, 19 



rature is needed during the spring and early summer when growth is 

 advancing. A free exposure to light and sun is requisite at all times. 

 The soil should consist of two-thirds sandy loam and one-third finely 

 broken bricks and lime rubbish. The pots must be well drained, and 

 water should always be carefully supplied, but much injury is often 

 done by keeping the plants too dry. They should be examined at least 

 once a week, even in the winter, and if the temperature is above 50° 

 and the weather bright they may be safely watered i£ they require it. 

 In colder quarters little wiU be needed during December and January. 

 These plants may be advantageously grown in a glass case, as this 

 protection keeps the dust from their beautiful spines. 



Propagation. — The majority of the tufted and branching species can 

 be readily increased, either by the offsets from the base, or by removing 

 the side branchlets. The former only need potting like ordinary plants, 

 keeping them rather dry until growth commences. The branchlets can 

 be laid upon dry soil until some roots show at the base, and they can 

 then be treated similarly. The more delicate sorts, or those that 

 produce few offsets, can be grafted on any Cereus, to which they 

 readily unite ; and this has a double advantage, for while the plants 

 often grow more strongly, they are also less liable to decay, as such 

 forms will do unless very great care is exercised in supplying water. 

 Cereus tortuosus and others of slender habit may be chosen for the 

 small-growing species. 



SELECT SPECIES. 



M. AKGULARis, Hort. Berol. — One of the more robust forms. The freely 

 branching habit gives it a very distinct appearance, and when well grown it 

 has a fine appearance. The largest specimen I have seen is in Mr. Peacock's 

 collection, and is over a foot in diameter ; in excellent health. DecandoIIe's 

 M. triacantha and M. cirrifera of some gardens (not of Martins) have been 

 regarded as varieties of this species, the last named corresponding to Salm'a 

 M. angularis var. fulvesoena. It can be readily increased by offsets. Intro- 

 duced in 1835. Strong-growing ; stem freely branched, 4 to 8 inches high, 

 2 inches in diameter ; tubercles conical, thick, a quarter of an inch long, having 

 a tuft of white down at the top, and four or five white spines of irregular 

 length ; flowers rosy purple. 



M. BICOLOK, Lehmann. — The whole surface of this plant appears as if 

 covered with a fine cobweb, owing to the numerous closely-set white hairs 

 which form the outer series of spines ; and if grown under a, case or in a 

 position where the dust can be excluded it is one of the most striking of the 

 genus. Some crested forms of this are grown, but they possess little beauty, 

 and are usually simply deformities. The species was introduced in 1835. 



