HYBRIDISING AND CROSS-BREEDING. 113 



simple enough in most cases, and consists in transferring the 

 dusty, wax-like, fibrous, or flour-like pollen from the anthers of 

 the male parent to the stigma or stigmatic surface of the 

 female organs. It matters not how the pollen is applied ; 

 powdery pollen may be applied with a fine-pointed camel's- 

 hair . pencil, or the tip of a feather : and here great care 

 is necessary to cleanse it thoroughly before operating on 

 another plant, as some pollen - grains may linger unseen 

 among the hairs, and become applied unwittingly to another 

 plant. In the case of such Orchids and Asclepiads as have 

 wax-like pollen masses, the point of a quill, toothpick, or 

 other little implement of similar form, may be used to transfer 

 the pollen from the anther - cases to the stigmatic cavity. 

 As a general 'rule, the stigma is borne at the end of a 

 column, or style, which is fleshy and three-lobed as in Tulip 

 or Lily, slender and fringed -at the apex as in many Cacti 

 and in Crocus, forked and set with hairs as in Asters, Mari- 

 golds, Sunflowers, and other Composites, or feather-like as 

 in corn -plants and grasses. For all practical purposes of 

 artificial fertilisation the size, shape, or position of the style 

 and the anthers is perfectly immaterial, the point being to 

 place the pollen carefully, and in sufficient quantity, on the 

 stigma just at the time when the pollen is perfectly ripe, 

 i.e., when it is naturally shed from the anthers, and when the 

 surface of the stigma is receptive that is, fully developed and 

 covered with a gummy or viscid secretion, the use of which 

 appears to be to retain the pollen when applied, and to favour 

 or promote the emission of the pollen-tubes, by which the 

 quickening connection is established and effected between the 

 pollen-grains, as applied to the viscid or hairy stigma, and the 

 ovules or young seeds. In the January number of ' Micro- 

 scopical Science,' 1866, is an interesting account of the 

 fecundation of Tigridia by Dr P. Martin Duncan and Dr 



DESCRIPTION OF ILLUSTRATION ON PRECEDING PAGE. 



A, Section of Narcissus flower enlarged, the tube purposely omitted, a, 4 pollen- 

 gratis -on tlie stigma, b, Style the black lines represent the course of the pollen-tubes 

 down the tissues of the style to the ovules or young seeds, c, Pollen-grain and pollen-tube 

 of Narcissus enlarged, d, Ovule enlarged ', showing the enlarged end of the pollen- 

 tube, which has entered the mouth of the seed in its embryo state so as to discharge 

 its vivifying contents and so fertilise or quicken the germinal vesicle shown in the 

 embryo sac at e. 



B, Ovule enlarged in section, i. Pollen-tube containing protoplasm or quickening 

 fluid. 2 and 3 represent cells', the upper, 2, forming a suspending body ', while the 



lower, 3, becomes the baby plant the incipient bodies a a, or one of them, becoming the 

 growing-point after fertilisation is effected. 4. Starch-grains. 



C, Pollen-grains of Dahlia emitting their tubes, which are shown passing down the 

 cellular tissues of tfie style. 



D, Pollen-grain of Grevillea emitting pollen-tube. 



H 



