Barbarea.] VI. CRUCIFER^]. 27 



very rarely all the lobes are narrow, or some of the leaves oblong and 

 undivided, but deeply toothed at the base. Flowers rather small, bright 

 yellow. Pods usually very numerous, erect or slightly spreading, and 

 crowded in a long dense raceme, each J to 3 inches long, terminated 

 by an erect, usually pointed style, varying from \ a line to 2 lines in 

 length. 



Hedges, or pastures and waste places, common all over Europe, in 

 Russian Asia and northern America. Frequent in Britain. Ft. spring 

 and swnmer. It varies much in the relative size of the lobes of the 

 leaves, in the size of the flowers, in the length and thickness of the 

 pod, in the length of the style, &c. A form with a very short and 

 thick style is often considered as a different species, under the names 

 of B. prcecox and B. intermedia, but it passes by every gradation into 

 those which have a pointed style of 2 lines, and which have again 

 been distinguished under the name of B. stricta. [Five forms or species 

 are recognised by botanists : — 



a. B. vulgaris proper. Flowers large, petals twice as long as the 

 sepals, pods in a dense raceme, erect, acute, three or more times as 

 long as their pedicels. Common. 



b. B. arcuata, Reichb. Flowers large, as in a. ; pods acute, large, 

 spreading on very long pedicels, style slender. Rare ; Armagh in 

 Ireland. 



c. B. stricta, Andrz. Flowers smaller, pods dense erect in a narrow 

 raceme, style slender. Uncommon. 



d. B. intermedia, Boreau. Leaves much cut, petals twice as long as 

 the sepals, pods acute erect in a dense raceme much longer than their 

 pedicels, style stouter. Cultivated fields. 



e. B. prcecox, Br. (American Cress). Leaves pinnatifid, segments 

 narrow, flowers large, pods long distant obtuse, pedicels short stout, 

 style very short and stout, seeds large. A garden escape ; an excellent 

 salad.] 



IV. NASTURTIUM. WATERCRESS. 



Glabrous perennials or annuals, with the leaves often pinnate, or 

 pinnately lobed, and small white or yellow flowers. Calyx rather 

 loose. Stigma capitate, nearly sessile. Pod linear or oblong, and 

 usually curved, or in some species short like a silicule, the valves 

 very convex, with the midrib scarcely visible. Seeds more or less 

 distinctly arranged in two rows in each cell, and not winged. Radicle 

 accumbent. 



A small genus, but widely spread over the whole area of the family. 

 It differs from Sisymbrium only in the position of the radicle in the 

 embryo ; and the white-flowered species are only to be distinguished 

 from Cardamine by the seeds forming two distinct rows in each cell of 

 the pod. 

 Pod usually \ an inch long or more. 



Flowers white 1. N. officinale. 



Flowers yellow . 2. N. sylvestre. 



Pod usually \ inch long or less. Flowers yellow. 



Pod oblong, curved. Petals scarcely longer than the calyx . 3. JV. pahistre. 



Pod ovoid, straight. Petals longer than the calyx . . .4. N. amphibium. 



1. N. officinale, Br. (fig. 52). Common W. — Stem much branched, 

 sometimes very short and creeping, or floating in shallow water ; 



