DICOTYLEDONES— THALAMIFLOE^ 



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stalked, generally pendulous ; embryo with the radicle variously 

 folded upon the cotyledons ; albume7i none, or very scanty. 



Diagnosis. — Generally ebracteate herbs. Inflorescence in- 

 definite ; racemose or corymbose. Sepals and petals 4, de- 

 ciduous, regular, the latter cruciate. Stamens tetradynamous. 

 Ovary with two parietal placentas ; stigmas 2. Fruit a siliqua 

 or silicula. Seeds stalked, with the radicle variously folded 

 upon the cotyledons. No other order is likely to be confounded 

 2vith this if ordinary care be taken, as tetradynamous stamens 

 only occur here, excejjt in a very feiv plants belonging to the 

 order Capparidacece. 



Division of the Order and Illustrative Genera. — This large 

 and truly ■ natural order has been divided into suborders 

 according to the nature of the fruit, and also as to the mode in 

 which the embryo is folded. The latter is the most natural 

 arrangement. 



The sub-orders founded on the nature of the fruit are as 

 follows : — 



Sub-order 1. Siliquosce. — Fruit a siliqua, opening by valves 



longitudinally. Illustrative Genera: — Cheiranthus, Linn.; 



Brassica, Linn. 

 Sub-order 2. Siliculosce latiseptce. — Fruit a silicula opening by 



valves; the replum in its broader diameter. Illustrative 



Genus : — Cochlearia, Linn. 

 Sub-order 3. Siliculosce angustiseptce. — Fruit a silicda opening 



by valves ; the replum in its narrower diameter. Illustrative 



Genera : — Capsella, Moencli ; Iberis, Linn. 

 Sub-order 4. NucumentacecB. — Fruit an indehiscent silicula ; 



often 1-celled, owing to the absence of the replum. Illustra- 

 tive Genus : — Isatis, Linn. 

 Sub-order 5. Sejntlatce. — The valves of the fruit opening lon- 



gitudinall}' and bearing transverse septa in their interior. 



There are no examples among British plants. 

 Sub-order 6. Lomentacece. — Fruit a siliqua or silicula, dividing 



transversely into 1-seeded portions, the true siliqua sometimes 



barren ; the beak placed above it containing one or two seeds. 



Illustrative Genera : — Cakile, Gaert.; Kaphanus, Linn. 



The arrangement of Bentham and Hooker is essentially the 

 same as the above. 



The sub-orders founded on the mode in which the embryo is 

 folded are as follows : — 



T 



