388 



ANOMALOUS MODES 



Chap. XI. 



4'' 



4> 



and organs. 87 The most remarkable fact about this tree is that in its inter- 

 mediate state, even when growing near both parent-species, it is quite 

 sterile ; but when the flowers become pure yellow or pure purple they yield 

 seed. I believe that the pods from the yellow flowers yield a full com- 

 plement of seed ; they certainly yield a large number. Two seedlings raised 

 by Mr. Herbert from such seed 88 exhibited a purple tinge on the stalks 

 of their flowers ; but several seedlings raised by myself resembled in every 

 character the common laburnum, with the exception that some of them had 

 remarkably long racemes : these seedlings were perfectly fertile. That such 

 purity of character and fertility should be suddenly reacquired from so 

 hybridized and sterile a form is an astonishing phenomenon. The branches 

 with purple flowers appear at first sight exactly to resemble those of 

 C. purpureus ; but on careful comparison I found that they differed from 

 the pure species in the shoots being thicker, the leaves a little broader, 

 and the flowers slightly shorter, with the corolla and calyx less brightly 

 purple : the basal part of the standard-petal also plainly showed a trace 

 of the yellow stain. So that the flowers, at least - in this instance, had not 

 perfectly recovered their true character ; and in accordance with this, they 

 were not perfectly fertile, for many of the pods contained no seed, some 

 produced one, and very few contained as many as two seeds ; whilst numerous 

 pods on a tree of the pure 0. purpureus in my garden contained three, 

 four, and five fine seeds. The pollen, moreover, was very imperfect, a 

 multitude of grains being small and shrivelled; and this is a singular 

 fact ; for, as we shall immediately see, the pollen-grains in the dingy-red 

 and sterile flowers on the parent-tree, were, in external appearance, in a 

 much better state, and included very few shrivelled grain. Although the 

 pollen of the reverted purple flowers was in so poor a condition, the ovules 

 were well-formed, and, when mature, germinated freely with me. Mr. 

 Herbert also raised plants from seeds of the reverted purple flowers, and 

 they differed very little from the usual state of 0. purpureus ; but this ex- 

 pression shows that they had not perfectly recovered their proper character. 

 Prof. Caspary has examined the ovules of the dingy-red and sterile 

 flowers in several plants of G. adami on the Continent, 89 and finds them 

 generally monstrous. In three plants examined by me in England, the 

 ovules were likewise monstrous, the nucleus varying much in shape, 

 and projecting irregularly beyond the proper coats. The pollen-gfains, 

 on the other hand, judging from their external appearance, were remark- 

 ably good, and readily protruded their tubes. By repeatedly counting, 

 under the microscope, the proportional number of bad grains, Prof. 

 Caspary ascertained that only 2*5 per cent, were bad, which is a less 

 proportion than in the pollen of three pure species of Cytisus in their 

 cultivated state, viz. C. purpureus, laburnum, and alpinus. Although the 

 pollen of C. adami is thus in appearance good, it does not follow, according 



87 For analogous facts, see Braun, 

 ' Eejuvenescence,' in ' Kay Soc. Bot. 

 Mem.,' 1853, p. 320 ; and ' Gard. Chron.,' 

 1842, p. 397. 



88 'Journal of Hort. Soc.,' vol. ii., 



1847, p. 100. 



89 See ' Transact, of Hort. Congress 

 of Amsterdam,' 1865 ; but I owe most of 

 the following information to Prof. Cas- 

 pary's letters. 



,r 



ember' 



