DENFARIA.] CRUCIFERJE. 29 



nearly nerveless, elastic ; septum membranous. /SMsl-ser'ate, compressed, 

 not margined, funicle dilated ; radical accumbent, stalked. DLSTRIB 

 N. temp, regions ; species about 20. ETYM. dens, from the scaly root-stock. 

 Differs from Cardamine chiefly in habit, and the funicles. 



1. D. bulbif'era, L. ; lower leaves pinnate, upper simple entire. 

 Woods arid copses, rare ; Stafford to Kent and S-issex; a doubtful native of 

 Scotland ; fl. April-June. Rootstock annual or biennial, white. Stem 1-2 

 ft., simple, leafless below. Leaflets 1-2 in., in few pairs, oMong, entire, 

 or serrate ciliate ; uppermost confluent at the base ; upper bulbiferous. 

 Flowers |-| in. diam., white or lilac; pedi -el slender. Pods erect, rarely 

 ripening. DISTRTB. Throughout Europe, rare in W. Asia. 



7. SISYM'BRIUM, L. HEDGE-MUSTARD. 



Annual or biennial herbs ; hairs simple. Radical leaves spreading ; 

 cauline alternate, often auricled. Flowers loosely racemed, usually yellow, 

 often bracteate. Sepals short or long. Petals often narrow and long- 

 clawed. Pods narrow-linear, terete or 4-6-angled or compressed ; valves 

 flat or convex, often 3-nerved ; septum membranous, nerveless or 2-nerved; 

 stigma simple 2-lobed or cup-shaped. Seeds many, 1-seriate, not mar- 

 gined ; radicle usually incumbent. DISTEIB. N. temp, and cold regions ; 

 rare in Southern ; species 80. ETYM. doubtful. Differs from Brassica 

 only in the flat ^cotyledons, and united to Arabis by S. Thaliana. Pods 

 of 4 types : 1. S. Thaliana, Irio, and Sophia ; 2. S. officinale ; 8. 8. 

 polyceratium ; 4. S. Alliaria. 



1. S. Thalia'na, Hook.-, leaves toothed pubescent, flowers white, pods 

 spreading or ascending obscurely 4-angIed. Thale-cress. 



Dry soils, from Orkney southd., ascends to 1,500 ft. in Yorks. ; Ireland ; 

 Channel Isld.s. ; fl. May-S^pt.- Annual. Stem 6-10 in., slender, nearly leaf- 

 less. Radical leaves rosulate, oblong, petioled ; cauHne narrow, sessile, all 

 entire or toothed. Flowers ^ in. diam. ; pedicel slender. Pods ^-f in., 

 slender, curved ; seeds minute ; radicle rarely accumbent. DISTKIB. 

 Europe (Arctic), to the Himalaya, N. Africa ; introd. in N". America. 



2. S. Ir'io, L. ; leaves runcinate-toothed or pinnatifid glabrous, flowers 

 yellow, pods terete slender suberect, London Rocket. 



A\ 7 'aste places, Berwick, Dublin ; Channel Islds.; sporadic elsewhere ; (a denizen, 

 Wats.) ; fl. July-Aug. Annual or biennial. Stem 1-2 ft., branched. Radi- 

 cal leaves petioled ; lobes irregularly toothed, terminal large often hastate. 

 Flowers^ in. diam. Pods Ij in., very many, glabrous, erect, strict; valves 

 bea led, 3-nerved ; style ; seeds oblong. DisfniB. Central and S. Euroj e, 

 N. Africa, W. Asia to the Himalaya. Called " London Rocket " because it 

 sprang up after the Fire of 1666. 



3. S. Sophi'a, L. ; leaves 2-3-pinnatifid glabrous or downy, segments 

 narrowly linear, flowers yellow, pods slender terete ascending curved, 

 p3dicels very slender. Flixweed, 



Waste places from Caithness southd., rarer in S-otlaud and Ireland; a 

 colonist? fl. June-Aug. Annual. Stem 1-3 ft,, branched above ; branches 



