CEUCIFERJE. (mustard FAMILY.) 63 



or else incumbent, viz. the back of one cotyledon applied to the radicle, 

 thus 00. In these cases the cotyledons are plane ; but they may be 

 folded upon themselves and round the radicle, as in Mustard, where they 

 are conduplicate, thus eg). In Leavenworthia alone the whole embryo is 

 straight. — Leaves alternate, no stipules. Flowers in terminal racemes 

 or corymbs : pedicels rarely bracted. — A large and very natural family, 

 of pungent or acrid, but not poisonous plants. (Characters of genera 

 taken from the pods and seeds ; the flowers being nearly alike in all.) 



I. SILTQUOSiE. Pod long, a silique, opening by valves. 



Tribe I. ARABIDE.^. Pod eloDgatcd (except in Nasturtium). Seeds orbicular or 



oval, more or less flattened. Cotyledons accumbent, plane. 



* Seeds small and turgid, seldom half the breadth of the turgid pod. 



I. Nasturtium. Pod terete, linear, oblong or even globular. Flowers white or yellow. 



* • Seeds flat or flattish, scarcely narrower than the partition, except in some of No. 5. 

 2- lieaTenivortliia. Pod oblong, flat} the valves nerveless. Seeds winged: embryo 



straight ! Flowers white or purplish, with a yellowish base. Leaves all radical. 

 8. Dentarla. Pod flat, lanceolate } the valves nerveless, opening elastically from the base. 

 Seeds wingless, on broad seedstalks. Flowers white or purple. Stem naked below. 



4. Cardamliie. Pod flat, linear or lanceolate; the valves nerveless, opening elastically. 



Seeds wingless, on slender stalks. Flowers white or purple. Stem leafy, at least below. 



5. Arabia, Pod linear, elongated, flat or flattish, rarely almost terete 5 the valves commonly 



with a prominent midrib, or veiny, not opening elastically. Flowers white, whitish, or 

 purple. Stems leafy, at least below. 



6. Barbarea. Pod linear, more or less 4-sided, the rigid valves being keeled by a promi- 



nent midrib. Seeds wingless. Flowers yellow. 

 Tribe II. SISYMBRIG.^. Pod elongated. Seeds thickish, mostly oblong. Cotyle- 

 dons incuQ)bent, narrow, plane. 



7. Kryslmum. Pod sharply 4-angled, linear. Flowers yellow. 



8. Sisymbrium. Pods terete, 4 -6-angled, or flattish. Flowers white or yellow. 



Tribe III. BRASSICGJ^Q. Pod linear or oblong. Seeds globular. Cotyledons in- 

 cumbent and conduplicate, folded round the radicle. 



9. Brasslca (Including Sinapis). Pod beaked or pointed beyond the end of the valves, 



or tipped with a rigid style, nearly terete, or 4-8ided. Flowers yellow or whitish. 



II. SILICULOSiE. Pod short, a silicle or pouch, opening by valves. 



Tribe IV. ALYSSINB.^. Pod oval or oblong, flattened parallel to the broad parti- 

 tion, or globular. Cotyledons accumbent, plane. 

 1. Nasturtium. Pod terete or globular with many small seeds. 



10. Draba. Pod flat, oval, oblong, or even linear, many-seeded. 



II. Alyssnm. Pod fiat, orbicular, 2 -4-seeded. 



12. Veslcaria. Pod globular-inflated, 4 -several-seeded. 



Tribe V. GAMBLING.^. Pod turgid or somewhat flattened parallel with the broad 

 partition. Cotyledons incumbent, narrow. 



13. Camellna. Pod pear-shaped, many-seeded : style slender. Flowers yellow. 



14. Subularla. Pod globular, few-seeded : style none. Flowers white. 



Tribe VI. LGPIDINBi^ and THLASPIDE^. Pod short; the boat-shaped 

 valves conduplicate or much flattened contrary to the narrow partition. Flowers white. 



15. Capsella. Pod many-seeded, obcordate-triangular, wingless. Cotyledons incumbent. 



16. Thlaspi. Pod several-seeded, obovate or obcordate, winged. Cotyledons accumbent. 



17. liepidlum. Pod 2-seeded, flat, scale-shaped. Cotyledons incumbent or accumbent. 

 IS. Seiieblera. Pod 2-seeded, didymous ; the valves rugose, separating at maturity from 



the little partition as two closed one-seeded nutlets. Cotyledons incumbent, narrow. 



