INCREASED NUMBER OF PARTS. 201 



is even more true of greatly multiplied stamens and pistils, as 

 in Magnolia and Liriodendron, most Anonaceae, Ranunculus, 

 Anemone, and the like. But in Aquilegia, where the number five 

 is fixed in the perianth, the cyclic arrangement with alternation 

 of whorls prevails throughout 



369. The definite augmentation of calyx and corolla b} r the 

 production of one additional whorl of each, and the seeming 

 anteposition which comes of it when the androecium remains 

 simply diplostemonous (in the manner of the Berberidaeeae, 

 Menispermaceae, &c., 359) has already been explained. 



370. Similar increase to two whorls affecting the corolla only 

 characterizes Anonaceae, Magnoliaceae, Papaveracese, and Fuma- 

 riaceae. In all but the last order, this is accompanied by indefi- 

 nitely multiplied stamens, and mostly by an increased number of 

 carpels. In Fumariaceae, which has dimerous flowers, there is a 

 diminution by the suppression in most cases of half the normal 

 andro2cium, and also an augmentation of the other half by 

 chorisis. (372.) 



371. Parapetalous Multiplication. Under this head may be 

 described an anomalous arrangement of augmented stamens 

 which prevails in the order Rosaceae, but is not peculiar to it. 1 

 The simplest case, but a rare one, is seen in the 10-stamened vari- 

 ety of some Hawthorns, as occasionally in Crataegus coccinea and 

 Crus-galli. The ten are in one circle and in pairs, the pairs 

 alternate with the petals. Some would say the pairs are before 

 the petals ; but the space between two stamens before each petal 

 is mostly rather wider than in the pair taken the other way. 

 The next case in order, as in 15-stamened Hawthorns, and 

 constantly in Nuttallia, adds to the above a simple interior circle 

 of five stamens, one directly before the middle of each petal. 

 Next, as in most Pomeae and many Potentilleae, there are twenty 

 stamens, thus placed, but with an additional circle of five alter- 

 nating with the preceding one. Next there are 25 in three 

 circles, the second circle as well as the first having ten stamens ; 

 and finally there are from 30 to 50, all probably in circles of ten 

 each. There is little doubt that the circles develop in centri- 

 petal order ; the inner successively the later. 2 



1 It was first clearly described by Dr. A. Dickson, in Trans. Bot. Soc. 

 Edinb. viii. 468, and Seemann's Jour. Bot. iv. 473 (1866). He introduced the 

 term, parapetalous, which is characteristic of it in its elementary form (254, 

 note) : it is particularly illustrated by Eiehler, in Bluthendiagramme, ii. 

 495-510. The former interprets it by chorisis, both median and collateral : 

 the latter presents the facts and possible views, but declines to adopt either 

 of them. 



2 Accordingly, the whole is probably to be explained by some modifica- 



