Chap. XVIII. CONTABESCENCE. 149 



the Linum, in the proportion of narcotin to morphine in the poppy, 

 in gluten to starch in wheat, when these plants are cultivated on 

 the plains and on the mountains of India ; nevertheless, they all 

 remain fully fertile. 



Contabescence. — Gartner has designated by this term a peculiar 

 condition of the anthers in certain plants, in which they are shri- 

 velled, or become brown and tough, and contain no good pollen. 

 When in this state they exactly resemble the anthers of the most 

 sterile hybrids. Gartner, 88 in his discussion on this subject, has 

 shown that plants of many orders are occasionally thus affected; 

 but the Caryophyllacese and Liliaceae suffer most, and to these 

 orders, I think, the Ericaceae may be added. Contabescence varies 

 in degree, but on the same plant all the flowers are generally affected 

 to nearly the same extent. The anthers are affected at a very early 

 period in the flower-bud, and remain in the same state (with one 

 recorded exception) during the life of the plant. The affection 

 cannot be cured by any change of treatment, and is propagated by 

 layers, cuttings, &c, and perhaps even by seed. In contabescent 

 plants the female organs are seldom affected, or merely become 

 precocious in their development. The cause of this affection is 

 doubtful, and is different in different cases. Until I read Gartner's 

 discussion I attributed it, as apparently did Herbert, to the un- 

 natural treatment of the plants ; but its permanence under changed 

 conditions, and the female organs not being affected, seem incom- 

 patible with this view. The fact of several endemic plants be- 

 coming contabescent in our gardens seems, at first sight, equally 

 incompatible with this view; but Kolreuter believes that this is 

 the result of their transplantation. The contabescent plants of 

 Dianthus and Verbascum, found wild by Wiegmann, grew on a 

 dry and sterile bank. The fact that exotic plants are eminently 

 liable to this affection also seems to show that it is in some manner 

 caused by their unnatural treatment. In some instances, as with 

 Silene, Gartner's view seems the most probable, namely, that it is 

 caused by an inherent tendency in the species to become dioecious. 

 I can add another cause, namely, the illegitimate unions of hetero- 

 styled plants, for I have observed seedlings of three species of 

 Primula and of Lyihrum saUcaria, which had been raised from 

 plants illegitimately fertilised by their own-form pollen, with some 

 or all their anthers in a contabescent state. There is perhaps an 

 additional cause, namely, self-fertilisation ; for many plants of 

 Dianthus and Lobelia, which had been raised from self-fertilised 

 seeds, had their anthers in this state ; but these instances are not 

 conclusive, as both genera are liable from other causes to this 

 affection. 



Cases of an opposite nature likewise occur, namely, plants with 



88 ' Beitra^e zur Kenntniss,' &c, s. setzung,' s. 57. Herbert, ' Amarylli- 

 117 et se/. : Kolreuter, ' Zweite Fort- daceae,' p. 355. Wiegmann, ' Uebei 

 setzung,' s. 10, 121 ; ' iJritte Fort- die Bastarderzeugung,' s. 27. 



