202 THE FLOWER. 



372. Chorisis or Deduplication. Both these terms, and the 

 ideas which they denote, originated with Dunal, but were first 

 expounded b}* Moquin-Tandon. 1 The first word is Greek for a 

 separating or separation. The second is a translation of Dunal's 

 French word dedoublement (literally undoubling) , the ambiguity 

 of which, and of the original presentation of the case, long 

 retarded the right apprehension of the subject. Diremption has 

 been suggested (by St. Hilaire) as a proper term. The mean- 

 ing simply is, the division of that which is morphologically 

 one organ into two or more (a division which is of course 

 congenital) , so that two or more organs occup}* the position of 

 one. As thus used, chorisis is restricted, or nearly so, to the 

 homologues of leaves in the flower, and mainly to stamens and 

 carpels ; the division or splitting up of a petal or a sepal, when it 

 occurs, being expressed in the phrases which are applied to leaves. 

 Yet a compound leaf, especially one of the palmate type, is 

 a good type of chorisis, the several blades of a compound leaf 

 answering to the single blade of a simple leaf. It has been ob- 

 jected against the terms chorisis and deduplication that they 

 assume the division of that which has never been united ; but 

 so equally does the established terminology of foliage. A di- 

 vided leaf has never been entire. 



373. Chorisis is complete when the parts concerned are dis- 

 tinct or separate to the very insertion, as in the stamen-clusters of 

 Hypericum. The foliar form of this would be represented by 



tion of the augmentation of circles. Dickson's hypothesis, that the two, 

 three, or five stamens which are more or less in face of each petal are all 

 deduplications of that petal, would come to be noticed under the next head, 

 but it may be dismissed at once. Yet that the pairs in the outer circle 

 represent each an antisepalous stamen, divided by chorisis (sometimes 

 incompletely) and much separated, is not improbable. The other tenable 

 explanation (which may be harmonized with the last) is that the outer 

 circle of stamens here rightly consists of ten members, respectively alternat- 

 ing with the sepals and petals taken as a whole. This makes them para- 

 petalous, and at the same time brings them under Hofmeister's general law 

 that new organs originate over intervals of those preceding, in this case over 

 the ten perianth-intervals directly. It also accords with Hartog's elucidation 

 of the accessory parts in the flower of Sapotaceae (in Trimen's Jour. Bot. 1878). 

 The inner circles are there sometimes 5-merous after the primitive type, 

 sometimes 10-merous in regular alternation to the preceding circles. 



1 Moquin-Tandon, Essai des Dedoublemens, &c., Montpellier, 1826; Con- 

 siderations sur les Irre'gularite's de la Corolle, &c., in Ann. Sci. Nat. xxvii. 

 237, 1832; Teratologie Ve'ge'tale, 337. Dunal, Essai sur les Vaccinie'es, 

 1819, cited by Moquin (some pages printed, but never published) ; Conside- 

 rations sur la Nature et les Rapports de quelques-uns des Organes de la 

 Fleur, 1829. The next botanist to develop it was St. Hilaire, Morphologie 

 Vegetale, 1841. 



