ROSALES.] 



FABACEiE. 



545 



regular-flowered genera with distinct stamens may be said to be Rosaceous in flower, and 

 Leguminous in fruit. Simple, therefore, as the diagnosis of this Order usually is. Brown 

 is perfectly con'ect in asserting that, until he indicated the diflference of the' position of 

 the odd lobe of the calyx in Leguminous plants and Roseworts, no positive character 

 had been discovered to distinguish the one Order from. the other. 



Very few double flowers are known in this Order ; those of Spartium junceum and 

 Ulex europaeus are the most remarkable ; the nature of the latter I have descriljed in 

 detail in the Trans, of the Uort. Soc. vol. 7. p. 237. Two ovaries are common in Wistaria 

 sinensis ; and the same phenomenon is to be seen, according to De Candolle, in Gle- 

 ditschia : it appears also to be normal in Diphaca and Caesalpinia dig}Tia. Aug. de St. 

 Hilaire is said {DC. Mini. 52) to have found a Mimosa in Brazil with 5 carpels. On 

 account of these and other circumstances, De Candolle assumes the carpel of Legumin- 

 ous plants to be solitary by abortion, and that a whorl of 5 is that which is necessary to 

 complete the sjTnmetry of the flowers. Of the accuracy of this view I am satisfied ; 

 and it might have been proved from analogy, without the aid of such instances.* 



In consequence of the highly irritable natiu'e of the leaves of many of the plants of 

 this Order, and of the tendency to ii^ritability discoverable in them all, some Botanists 

 have placed them at the extremity of their system, in contact with the limits of the 

 animal kingdom. See Agardh. Classes, p. 4, and MaHius IT. R. M. p. 176. For obser- 

 vations upon the natm'e of this irritability, see Dutrochet sur la Motilite, Paris, 1824, in 

 which the author endeavours to show that the motion is the effect of galvanic agency ; 

 and the same v^Titer's Nourelles Recherches sur VKcosmose, cC-c, in which he alters the 

 explanation of the manner in which galvanism produces the motion, adhering, however, 

 to his opmion of that sul)tle principle being the real agent. To me, however, it appears 

 more satisfactory to attribute the phenomenon to an inherent vital action, without search- 

 ing after first causes, which it is impossible, from the nature of things, to investigate. 



In many respects tliis Order is one of the most impoi*tant which the Botanist can 

 study ; more especially as it serves to show how httle real importance ought to be 

 attached to dehiscence of fruit in determinmg the hmits of Natm*al Orders. What may 

 be called the normal finiit of Leguminous plants is a legume, that is to say, a dry simple 

 carpel, %sith a suture running along both its margins, so that at maturity it separates 

 through the line of each sutui'e into two valves ; but every conceivable degree of 

 de%dation from this tj-pe occurs : Arachis and many more are indehiscent ; in Car- 

 michseUa the valves separate from the suture, which remains entu'e, Uke the replvun of 

 Crucifers ; in all lomentaceous genera, such as Omithopus, the valves are indehiscent 

 in the hne of the sutm^e, but separate transversely ; in Entada a combination of the 

 pecuUarities of Carmichselia and Lomentacese occm's ; in Hsematoxylon the valves 



* The plan of what must be regarded as the normal form of Leguminous structure, will be gathered 

 from the following diagrams, in which fig. 1 . represents the arrangement that occurs in Afifonsea ; 2. the 



^^^^ ^ ^ ^- ^^ ,^ ;^^ 



d / ^ ^ \ , 7 / \d 



theory of the ordinary papilionaceous condition; and 3. the actual state of such a flower I"^*^^:!-^"^ 

 2. 6 are the sepals; d the petals; b c stamens; a the abortive •^'^^P^^'' = •'', "^^, ^,^J^^*1?X ' 

 imaginary axis! In fig. 3. g is the ovary; h the tenth free stamen ;r c the tube pl.t abo^e and 

 co^isting of nine other stamens ; d d the two petals that form a canna ■ d <* .the t^jo wmgs . / the 

 vexiUum ; e e sepals. These are taken from a paper by Walpers, in Am. Kat. msx. v. ini. 



N N 



