Polytechnic Association Proceedings. 967 



aud where the anthers are few, as in the diandna, triandria, &c., 

 small pincers may be employed, or a bit of wire so twisted to form 

 that implement, to carry in the pocket, is by far the handiest. 



5. In some cases it is difficult to procure and preserve pollen. 

 In dioecious plants, like the aucuba, it may be essential to store 

 the pollen until the female plant, which is generally eaten, comes 

 to flower. Many hold that pollen cannot be preserved in a vital 

 condition for more than one or two, or perhaps three weeks. Wichura 

 of Germany, in his recent work on Hybridization, holds it as "a 

 fact of great importance that the pollen of willows retains its 

 potency for some time. In some cases pollen ten days old w^as 

 efficient, while vitality was still further prolonged by steeping it in 

 a solution of honey. Pollen of salix-salesiaca (willowworts) eight 

 days old seemed almost as potent as ever; in twenty-eight days the 

 traces of vitality wery very slight, while that of salix-cinerea had 

 become weak in sixteen days." On the other hand, he (Mr. Henry), 

 had carried in his pocket the pollen of rhododendron^ and of the 

 Japanese forms of the genus Ulium, again and again from six weeks 

 to two months and upward, and still found it potent. Having, in 

 1866, got the new and beautiful clematis-jackmanii to flower, on 

 the 4th of July he gathered its anthers, and stored them in a simple 

 pill-box placed in a cabinet di"awer, and on the 5th of Jime, 1867, 

 having carefully emasculated a flower of dematis-candtda, he crossed 

 it with the pollen then eleven months old, and from this cross he 

 had gathered and sown, last autumn, eight well developed seeds. 

 Both parents were hybrids, with a large infusion of alien blood in 

 them, so that in this case the vitality'' was put to the severest test. 

 The result is noticed here to suggest the propriety of storing, and, 

 if needful, of importing pollen, which, if wrapped up in silk paper, 

 or even inclosed in a letter, might reach Scotland still potent, by 

 the overland route from India, or, after two or three months' voyage, 

 from all parts of North and South America. Let friends and col- 

 lectors in distant countries be instructed as to this, and we may 

 soon have an improved progeny of the rarest things, even before 

 such novelties from which they are derived have been obtained 

 from theu' own seeds. 



6. Another matter of much consequence in crossing distant 

 species is the times and seasons for efiecting.the cross; yet not one 

 most experienced in the art, from Darwin downward, have touched 

 upon this point. Such times occur, often few and far between, 

 when there is less of sun than of that form of latent heat which is 



