Order 13.— CETJOIPER.^. 227 



by a false partition, with parietal placeatse. Fruil a silique, or silicle, usually 2- 

 celled. Stigmas 2, sessile. Seeds 2-rowed in each cell, but often so intercalated 

 as to form but one row, Emhryo with the 2 cotyledons variously folded on th« 

 radicle. Alhumen 0, 



IllHSt. 25G, 312, 865, 44T, 443. 



Qenera'\^^, species 16dO. This is a very natural order, larger than any of the preceding. 

 The greater part of the spocies are found ia the temperate zones. Abo.it 100 are peculiar to 

 this continent. 



Properties. The Crncif^s as a class are of much importance to man. They furnish several 

 alimentary articles, which are very nutritious, as the Turnip, Cabbage, Cauliflower; several 

 others are used as condiments, as Mustard, Radish, Cochlearia, etc. They all possess a peculiar 

 acrid, volatile principle, dispersed through every part, often accompanied by an etherial oil 

 abounding in sulphur. Tiiey are also remarkablu lor containing more nitrogen than other vege- 

 tables, for which reason ammonia is generally evolved in their putrefaction. In medicine ther 

 are eminently stimulant and antiscorbutic. None are really poisonous, although very acrid. 

 The root of Isatis tinctoria alfords a blue coloriug matter. 



Ohs. The genera of this largf^ nrdfr wo-n nrrancpd into sub-orders by TiQ Candolle, according 

 to their various modes of folding the cotyleddu u|*on the latliclf, which luodes are as follows: 

 1. Cotyledons accuuibent, the radicle turned round and applied to the edges of the cotyledons, 

 represented thu8 0=. 2. Cotyledons incumbent, the radicle applied against the back of one of 

 the cotyledons, II . 3. Cotyledons conduplicate, radicle folded as in the last case, but the coty- 

 ledons bent 6o as partly to enfold it, 0J>>', as in the mustard. 



In the analysis of the Crucifers it is indispensable that the specimens be in fruit as well as 

 flower, and that the student bring to bear all his patience and resolution in the study of the 

 above and other forms of structure in the seed, however minute. In the following synopsis the 

 student may use in analysis either the artiflcial arrangement of tho Genera or the less obvious 

 but moro natural arrangement of the 



TRIBES. 



5 SILIQUOS^,— fruit a siliquo opening by valves. (Tribes.) 



Tribe 1. ArabidejE. Seeds flattened, often bordered ; cotyledons 0= Genera 1 — 10 



Tribe 2. Sisimuee^. Seeds oblong, not bordered ; cotyledons || Gon. 11 — 14 



Tribe 3. Brassicb^. Seeds globular, cotyledons 0», Flowers yellow Gen. 15, 16 



§§ BILICULOSJE,— fruit a silicle opening by valves when moro than 2-seeded. (Tribes.) 



Tribe 4. Alyssinb^. Dissepiment broad. Cotyledons 0= Gen. IT — 21 



Tribe 5. Cameline^. Dissepiment broad. Cotyledons II Gen. 22, 23 



Tribe 6. Tiilaspe^e. Dissepiment narrow. Cotyledons 0= Gen. 24 



Tribe 7. Lepidine^. Dissepiment narrow. Cotyledons || ....■ Gen. 25—27 



Tribe 8. IsATiDEiE. Dissepiment 0. Silicle 1-seeded, indehiscent Gen. 28 



S§§ LOMENTACEjE,^fruit a jointed silique, partitioned across. (Tribes.) 



Tribe 9. Cakaline^e. Cotyledons 0=, seeds compressed Gon. 29 



Tribe 10. Kaphahe^. Cotyledons 0», seeds globous. Gen. 30 



ARTIFICIAL KEY TO THE GENERA. 



§ Fruit a silique. Seeds in a double row General, 2 



Seeds in a single row. Flowers cyanic (a). 

 Flowers xanthic (b) 



a Flowers purple, single. Stigma capitate. Plant native Genera 8 



a Flowers purple (or white and double). Stigmas horned. Cultivated Gen. 4, 14 



a Flowers white or roseate. Siliques flattened,— raised on a filiform stipe Gen. IS 



—sessile, having no stipe Gen. 5, 6, T 



b Seeds globular, with cotyledons conduplicate (0») Gen. 15, 16 



b Seeds oblong or lens-shaped. Siliques terete or flattened, veinless Gen. 8, 9 



Siliques squarish, valves 1— 8-veined Gen. 10, 11, 12 



§§ Fruit a silicle. Silicle turgid or flattened, with a broad partition (c). 

 Silicle flattened contrary to the narrow partition (d). 



Silicle with no partition, 1-seeded. Flowers yellow Gen. 28 



C Ornamental exotics, variously colored. Gardens Gen. 17, IS 



e Native plants with— flowers cyanic, white Gen. 19,20, 25 



—flowers yellow. > Silicles ? oblong Gen. 1 



Silicles ovoid or globular Gen. 21, 23 



d Seeds several in each cell. Silicle triangular Gen. 25 



d Seeds only 2,— one in each cell. The two outer petals larger Gen. 24 



The petals all equal Gen. 26,27 



§§§ Fruit a loment, jointed and partitioned across ..Gen. 29,30 



