DICOTYLEDONES— THALAMIFLOE^ 275 



stalked, generally pendulous ; embryo with the radicle vaTiously 

 folded upon the cotyledons ; albumen 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 lihely to be confounded 

 with this if ordinary care be taken, as tetradynamous stamens 

 only occur here, except in a very fexu plants belonging to the 

 order Capparidacece. 



Division of the Order and Illustrative Gemera. — This large 

 and truly natural order has been divided into sub orders 

 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 vahcs 

 longitudinally. Illustrative Oenera : — Cheiranthus, Linn.; 

 Brassica, Linn. 



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

 valves; the replum in its broader diameter. lUusirative 

 Genus .-^Cochlearia, Linn. 



Sub-order 3. Siliculoscc angvsiiscpta. — Fruit a silicvJa opening 

 by valves ; the replum in its narrower diameter. Illustrative 

 Genera : — Capsella, Moench ; Iberis, Linn. 



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

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

 tive Genus : — Isatis, Linn. 



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

 gitudinally 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, Oaerf. ; Eaphanus, 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 ; — 



