14 

 IX. CRUCIFER^E. The Cruciferous Tribe 



Crucifeb*. Juss. Gen. 237. (1789); Dec. Memoire sur les Cruciferes (no date) ; Syst.2. 139. 

 (1821) ; Prodr. 131, (1824) ; Lindl. Synops. 20. (1829.) 



Diagnosis. Polypetalous dicotyledons, with hypogynous tetradynamous 

 stamens. 



Anomalies. Schizopetalum has 4 cotyledons; sometimes the petals are 

 abortive. 



Essential Character. — Sepals 4, deciduous, cruciate. Petals 4, cruciate, alternate with 

 the sepals. Stamens 6, of which two are shorter, solitary, and opposite the lateral sepals, oc- 

 casionally toothed ; and four longer, in pairs, opposite the anterior and posterior sepals ; gene- 

 rally distinct, sometimes connate, or furnished with a tooth on the inside. Disk with various 

 green glands between the petals and the stamens and ovarium. Ovarium superior, unilocular, 

 with parietal placentje usually meeting in the middle, and forming a spurious dissepiment. 

 Stigmata two, opposite the placenta. Fruit a siliqua or silicula, 1 -celled, or spuriously 

 2-celled ; 1- or many-seeded ; dehiscing by two valves separating from the replum ; or inde- 

 hiscent. Seeds attached in a single row by a funiculus to each of the placentse, generally pen- 

 dulous. Albumen none. Embryo with the radicle folded upon the cotyledons. — Herbaceous 

 plants, annual, biennial, or perennial, very seldom suffruticose. Leaves alternate. Flowers 

 usually yellow or white, seldom purple. 



Affinities. This order is among the most natural that are known, and its 

 character of having what Linneean botanists call tetradynamous stamens is 

 scarcely subject to exception. It has a near relation to Capparideee, Papave- 

 raceee, and Fumariaceee. With Capparideee it agrees in the number of the 

 stamens of some species of that order, in the fruit having two placentse and a 

 similar mode of dehiscence, and in the quaternary number of the divisions of 

 the flower. To Papaveraceee, it approaches in the number of the petals, an 

 unusual number to prevail in dicotyledonous plants, and again in the structure 

 of the fruit of some genera of that order, such as Glaucium and Chelidonium. 

 With the siliquose-fruited Fumariacese it has much analogy, and even with 

 the whole of that order in the number of its petals, supposing the common 

 opinion of the nature of the floral envelopes of Fumariaceee to be correct, or 

 in the binary division of its flower, from which the quaternary is only a slight 

 deviation, upon the hypothesis I have suggested in speaking of that order. 



Cruciferee may be said to be characterized essentially by their deviation from 

 the ordinary symmetry observable in the relative arrangement of the parts of 

 fructification of other plants, — deviations which are of a very interesting na- 

 ture. Their stamens are arranged thus : two stand opposite each of the ante- 

 rior and posterior sepals, and one opposite each of the lateral sepals ; there 

 being 6 stamens to 4 sepals, instead of either 4 or 8, as would be normal. 

 Now in what way does this arise ? is the whorl of stamens to be considered 

 double, one of the series belonging to the sepals, and one to the petals, and, of 

 these, one imperfect 1 I am not aware of any such explanation having been 

 offered, nor do I know of any better one. It appears to me that the outer series 

 is incomplete, by the constant abortion of the stamens belonging to the anterior 

 and posterior sepals. But it is in their fruit that their great peculiarity consists. 

 I transcribe the following observations upon this subject from the Botanical 

 Register, fol. 1168, in which I have entered in some detail into the inquiry. 



" It is well known, that in regularly-formed fruits the style or stigma univer- 

 sally and necessarily alternates with the placenta, for reasons which it would 

 be superfluous to insist upon in this place. But in Cruciferae the stigmata are 

 opposite to the placenta?, terminating a sort of frame or replum, the two sides 

 of which are often connected by a membranous septum, on the outside of 

 which latter the ovula are arranged in a single row on each side ; so that in 



