330 



CASSELL'S POPULAE GARDENING. 



greatest freedom under domestication, and the re- 

 sulting progeny is perfectly fertile. 



The method of procedure is simple. First of all, 

 carefully remove the stamens of the plant to he 

 operated upon, procure pollen from an older flower 

 of the intended male parent, and having applied it 

 to the pistil of the flower to he operated on, with a 

 camel's-hair pencil, cover the flower with fine net- 

 ting to prevent any further access of pollen. 



The genus Sosa includes ahout thirty good spe- 

 cies, hut so variahle are they, even in a state of 

 nature, that authors entertain extreme opinions as 

 to the number that ought to he admitted as species. 

 Ahout two hundred and fifty are enumerated, and 

 many would find no difficulty in augmenting the 

 list to douhle that number. Du Hamel says that 

 "nature appears scarcely to have placed any dif- 

 ference between the different species of Eose ; and if 

 it is already very difficult to define the wild species, 

 which have not yet been modified by culture, it 

 is almost impossible to refer to their original type 

 the numerous varieties which culture has made in 

 the flowers of species already so nearly resembUng 

 each other." If we comprehend the full meaning of 

 this extract, there will be little difficulty in under- 

 standing why the numerous forms offer such facili- 

 ties for the almost indiscriminate intercrossing 

 known to exist under cultivation. The stamens are 

 exceedingly numerous in many series, aiid come to 

 maturity at the same time as the pistil. The styles 

 are also numerous and collected in a bundle just 

 protruding from the throat of the calyx, or projecting 

 beyond it some distance in a single column, as in 

 R. Brunonii, and our native R. arvensis : most favour- 

 able conditions for the success of the hybridist. 



When about to hybridise two species, select the 

 earliest and best flowers, and carefuUy protect them 

 from insect or other intruders, even for some time 

 previous to their expansion. As soon as this hap- 

 pens, remove the stamens immediately from the in- 

 tended seed-bearer, and apply the pollen of the male 

 parent, when the stigmas are in a receptive condition. 

 Protect as before until aU danger of fereign pollen 

 taking effect is over. 



Notwithstanding the fact that about one hundred 

 and seventy species of Pelargonium are known, the 

 cultivated varieties at present grown are the descen- 

 dants of four or five original species. This is the 

 more remarkable, considering the varied and endless 

 diversity of habit and foliage to be found in the 

 genus. The bedding or zonal section have been ob- 

 tained from the numerous interbred progeny of 

 P. zonule and P. inquinans ; the Ivy-leaved section 

 from P. peltatum, and the show and fancy varieties 

 from P. cttcullatiim. The flowers of the genus are 

 proterandroua, that is, the anthers are ripe before 



the stigma, each containing ten stamens, of which 

 seven are fertile, rarely fewer. "When the anthers 

 are mature and about to shed their pollen, they 

 occupy a central position, whUe the pistil is scarcely 

 at all visible. One by one the anthers shed their 

 pollen and drop away. The pistil now develops, 

 and when the five radiating stigmas have f uUy ex- 

 panded, a velvety-looking, or pubescent line, along 

 the upper or inner face of each, proclaims that they 

 are ready for fertilisation. The operator will now 

 see that the flowers to be pollenised must be of 

 different ages, that is, the pollen to fertilise any 

 given flower must be obtained from a younger, or 

 one just expanded. There are exceptions to this 

 rule, however, in some of the pale-flowered mongrels 

 of P. zonale and inquinans, where the pistil tends to 

 early maturity, and being short, is fertilised by its 

 own pollen. This is very evident in the variety 

 Christine, which persistently sets itself freely, 

 especially when planted out of doors. The careful 

 hybridist, however, will take measures in advance of 

 this, and remove the anthers as well as protect the 

 flowers at an early date. He will also carefully 

 tabulate or label the flowers operated upon, for 

 future reference. 



The vast order of Orchids, containing some four 

 or five thousand well-marked species, is becoming 

 yearly of more engrossing importance, not only from 

 a popular, but a scientific point of view. The hy- 

 bridisation of Orchids is only in its infancy, hut 

 unfortunately there is little prospect of its ever 

 becoming so universally practised in gardens as 

 on many popular florists' flowers, not merely on ac- 

 count of their value, but their slow rate of increase, 

 and the difficulty of rearing them in our compara- 

 tively sunless winter seasons. The art is by no 

 means so difficult to learn as would at first sight 

 appear, although the natural process is often very 

 complicated indeed, and sometimes almost inexplic- 

 able. 



The extraordinary construction of an Orchid 

 presents the most serious difficulty. The segments 

 of the perianth, known as sepals, petals, and 

 labellum, six in number, present endless modifica- 

 tions in shape, direction, and colour ; hut the column, 

 consisting of the amalgamated style and six stamens, 

 is even more disguised in its homologies with the 

 same parts in other flowers. 



The ways and means by which the members of 

 these different groups are fertilised in a state of 

 nature are extremely numerous and often com- 

 plicated. In effecting artificial hybridisation, how- 

 ever, all that is necessary is to remove the pollinia 

 from the anther-cells, and transfer them to the 

 viscid stigma of the intended female parent. The 

 chief difficulty attending the operation is the incon- 



