GRUCIFEEJS. 



183 



Notoceras 

 hispanicum. 



Fig. 206. 

 Fruit. 



is closely folded on the cotyledons. It is applied to their edges and 

 therefore termed accumbent. 



Cheirantkus comprises herbs and imdershrubs with fine bifurcated 

 or more rarely stellate hairs scattered over their organs. 

 Their leaves are alternate, simple, elongated, entire or 

 dentate. Their flowers form terminal racemes, in which 

 the alternate pedicels are not axillary to bracts. In some 

 species 1 with all the other characters of the genus the 

 radicle is incumbent, that is applied not to the edges of the 

 cotyledons, but across the side of one of them. The genus 

 comprises a dozen species, 2 natives of the temperate regions 

 of Europe, "West and Central Asia, North Africa, and North 

 America. 



The Rock-cresses {Arabis ; Fr., Arabette), closely allied to 

 the Wallflowers, especially in fruit, are only distinguished 

 therefrom by characters that would be held of slight value in other 

 genera, but which here rise greatly of necessity, when we have to divide 

 so close and natural an order into genera. The 

 lateral sepals are sometimes like the other two. 

 The siliqua is thin linear compressed sessile, 

 and its valves are plane or carinate (figs. 206- 

 208). The seeds are arranged in one row, 

 more rarely in two, on either side of the false 

 septum, and may be marginate or even winged, 

 or else wingless. Arabis has given its name 

 to the first subseries in this group, the Arabi- 

 dinete, usually 3 characterized by the accumbent 

 radicle. Therein are included twenty genera : 

 Cheirantkus, Atelanthera, Nasturtium,* Barbarea, 

 Arabis, Streptanthus, Cardamine (figs. 204, 205), 

 Dryopetalum, Macropodlum, Leavenworthia, 



Parolinia ornata. 



Fig. 207. 



Fig. 208. 



Gynajceuin (^). Long. sect, of 

 gynseceum. 



1 Especially in C. Menziesii {Hesperis 

 Menziesii Hook., in Beech. Toy., Bot., t. 75), 

 type of the genus Phcenicaulis (NlTTT., ex Tobe. 

 & Gb., Fl. N. Amer., i. 89). The same thing 

 occurs at tunes in C. Cheiri and the allied species 

 of our gardens. 



2 Reichb., Ic. Fl. Germ., t. 45. — Boiss., Fl. 

 Or., i. 185. — Geen. & Godb., Fl. de Fr., i. 



86. — Walp., Rep., i. 121; ii. 755; Ann., iv. 

 192 ; vii. 98. 



3 Here, as in Cheirantkus and generally in the 

 memhers of this order, this character is, as we 

 shall see, though convenient in practice, far from 

 absolute, and many exceptions to it have been 

 cited. (See Adansonia, x. 48.) 



4 According to A. Geay, we should regard 



