334 LEAVES FROM MY NOTE-BOOK. 



laburnum, and the bud lay dormant, as often happens, for a year. 

 The shield then produced many buds and shoots, one of which 

 grew more upright and vigorous, with larger leaves than shoots of 

 C. purpureus^ and was consequently propagated. Now, it deserves 

 especial notice that these plants were sold by Mr. Adam as a 

 variety of C. purpureus before they had flowered, and the account 

 was published by Poiteau after the plants had flowered, but before 

 they had exhibited their remarkable tendency to revert into the 

 two parent species, so that there was no conceivable motive for 

 falsification. ... If we admit Mr. Adam's account as true, 

 we must admit the extraordinary fact that two distinct species can 

 unite by their cellular tissue and subsequently produce a plant, . 

 . . resembling in every important respect a hybrid formed in 

 the ordinary way by seminal reproduction" (p. 417). 



Throughout Europe, in different soils and under different 

 climates, branches of the Cytisus Adanii have repeatedly and sud- 

 denly reverted to the two parent species in their flowers and leaves. 

 To see mingled on the same tree tufts of dingy red, bright yellow, 

 and purple flowers, borne on branches having widely different 

 leaves and manner of growth, is a surprising sight. " I have seen 

 a single flower," says Darwin, " divided into halves, one side being 

 bright yellow and the other purple, so that one half of the stan- 

 dard petal was yellow and of larger size and the other half purple 

 and smaller." The most remarkable fact about this tree is that in 

 its intermediate state, even when growing near the parent species, 

 it is quite sterile ; but when the flowers become pure yellow or 

 pure purple, they yield seed. . . . Two seedlings reared by 

 Mr. Herbert from the seed of yellow flowers exhibited a purple 

 tinge in the stalks of their flowers ; but several seedlings raised by 

 Darwin resembled in every character the common laburnum, with 

 the exception that some of the stems had extremely long racemes. 

 These seedlings were perfectly fertile. That such purity of 

 character and fertility should be suddenly recognised in so sterile 

 a form is an astonishing phenomenon. Darwin proceeds to enter 

 into minute details as to the condition of the ovules and pollen in 

 the sterile forms. 



The famous bizzaria orange offers a strictly parallel case to 

 that of Cytisus Adavii. The gardener who in 1644 in Florence . 



