CRUCIFERAE. 



"3 



Family 41. CRUCIFERAE, Mustard Family. 



Herbs, rarely somewhat woody, with watery sap; leaves alter- 

 nate; stipules none; flowers perfect, regular, in usually bractless 

 racemes, spikes or corymbs; sepals 4, usually oblong; petals 4, 

 rarely none, hypogynous, in the form of a cross, equal, generally 

 clawed, alternate with the sepals; stamens 6, rarely fewer, 

 hypognyous, of unequal length, the two shorter opposite the 

 sepals, the four longer opposite the petals; pistil 1, of two united 

 carpels; pod usually 2-celled, dehiscing by the separation of two 

 valves from the central partition, or rarely indehiscent, either 

 much longer than broad (a silique) or short (a silicle). 



Pods indehiscent. 



Fruit winged; pubescence of simple hairs. ISS. 



Fruit wingless; pubescence of branched hairs. 156. 

 Pods dehiscent, 2-valved, either elongate (siliques) 

 or short (silicles). 

 Pods elongate (siliques). 



Siliques compressed parallel to the broad 

 partition. 

 Valves nerveless; leaves all petioled. 

 Valves 1-nerved; cauline leaves sessile. 



Siliques lanceolate. 158. 



Siliques linear. 159. 



Siliques terete, not at all compressed. 

 Pods 4 cm. long or more. 



Flowers white or red ; stigmas entire ; 



pods erect. 

 Flowers yellow; stigmas 2-lobed; 

 pods spreading. 

 Flowers large; leaves nearly en- 

 tire. 161. 

 Flowers small; leaves pinnatifid. 164. 



Pods less than 4 cm. long. 



Siliques beaked; seeds globose. 

 Siliques beakless; seeds oblong. 

 Valves of the pods nerveless. 

 Valves of the pods nerved. 



Annuals; leaves pinnate or 



pinnatifid. 164. 



Perennials; leaves lyrate. 165. 

 Pods short (silicles). 



Silicles compressed parallel to the partition. 

 Flowers solitary on scapes, white; seeds 



winged. 

 Flowers racemose; seeds wingless. 



Silicles orbicular. 167. 



Silicles ovate or oblong. 168. 



Silicles either not compressed or compressed 

 contrary to the partition. 



Thysanocarpus, 114. 

 Athysanus, 114. 



157. Cardamine, 115. 



Phoenicaulis, lis. 

 Arabis, us. 



160. Thelypodium, 117. 



Erysimum, 117. 

 Sisymbrium, 119. 



162. Brassica, 118. 



163. Radicula, 118. 



Sisymbrium, 119. 

 Campe, 120. 



166. Platyspermum, 120. 



Alyssum, 120. 

 Draba, 121. 



