AND CROSS-BREEDING. 151 



5th. In some cases it is a matter of some difficulty to pro- 

 cure, and when procured of no less importance to preserve, 

 pollen. In dioecious plants say the Aucuba a friend may 

 have the male, and you have, as we all have, the female in 

 abundance. You would like to store that pollen till your 

 female plant, generally later, comes into flower. Many hold 

 that pollen cannot be preserved in a vital condition for more 

 than one or two, or perhaps three weeks. In a recent publica- 

 tion which refers to this matter namely, Max Wichura's ' Ob- 

 servations on Hybridisation,' of which a very lucid abstract, 

 carefully digested and translated from the original German by 

 the Rev. M. J. Berkeley, is given in the January number of 

 the 'Journal of the Royal Horticultural Society' for 1866, 

 that eminent authority 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 was efficient, while vitality 

 was still further prolonged by steeping it in a solution of 

 honey " (of which I have doubts). " Pollen," he adds, " of 

 Salix silesiaca eight days old seemed almost as potent as 

 ever; in twenty-eight days the traces of vitality were very 

 slight, while that of the Salix cinerea had become weak in six- 

 teen days." Now I am not aware that there is less vitality in 

 the pollen of Willows than in that of any other family; and as 

 many experimentalists hold kindred views to those here enun- 

 ciated by Wichura, I deem it a matter of some importance to 

 give you one or two instances of my own experience. I have 

 carried in my pocket the pollen of Rhododendron again and 

 again from six weeks to two months and upwards, and still 

 found it potent. Of the Japanese forms of the genus Lilium 

 I have kept pollen effective in the same manner for equal 

 periods. In fact, generally speaking, I have found the pollen 

 of most plants to remain good for similar periods. Having 

 last year got the new and beautiful Clematis Jackmanii to 

 flower, and anxious to preserve its pollen as long as possible, I 

 collected and stored it in its anthers in a simple pill-box. On 

 the 4th of July 1866, I so gathered and put it into a drawer 

 of a cabinet in my own sitting-room, where it remained wholly 

 away from damp. On the 5th of June 1867, having first care- 

 fully emasculated a flower of Clematis Candida, I crossed it 

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

 I have this autumn gathered and sown eight well-developed 

 seeds. Now both parents are hybrids, with a large infusion of 

 alien blood in them, so that here the vitality was put to its 

 severest test. Subsequent experiments satisfy me that the 

 vitality of all pollen may not be so long preserved, for I have 



