Dentaria.] CRUCIFFRJEJ. 29 



nearly nerveless, elastic ; septum membranous. Seeds 1-ser' ate, compressed, 

 not margined, funicle dilated ; radical accumbent, stalked. — Distrib 

 N. temp, regions ; species about 20. — Etym. dens, from the scaly rootstock. 

 — Differs from Cardamine chiefly in habit, and the funicles. 



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

 Woods and 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, oblong, entire, 

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

 Flowers §-§ in. diam., white or lilac; pedicel slender. Pods erect, rarely 

 ripening. — Distrib. Throughout Europe, rare iu W. Asia. 



7. SISYMBRIUM, 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.— Distrib. N. temp, and cold regions ; 

 rare in Southern ; species 80. — Etym. doubtful. — Differs from Brassica 

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

 of 4 types : — 1. S. Thaliana, Irio, and Sophia; 2. S. officinale; 3. S. 

 polyceratium ; 4. S. Alliaria. 



1. S. Thalia'na, HooTc.; leaves toothed pubescent, flowers white, pods 

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



Dry soils, from Orkney southd., ascends to 1,509 ft. in Yorks. ; Ireland ; 

 Channel Islds. ; fl. May-Sept. — Annual. Stem 6-10 in., slender, nearly leaf- 

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

 entire or toothed. Floivers % in. diam. ; pedicel slender. Pods *>-§ in., 

 slender, curved; seeds minute; radicle rarely accumbent. -Distrib. 

 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. 



Waste 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 1| in., very manv, glabrous, erect, strict; valves 

 healed, 3-nerved ; style ; seeds oblong. — Distrib. Central and S. Europe, 

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

 sprang up after the Fire of 1666. 



3. S. Sophia, L. ; leaves 2-3-pinnatifid glabrous or downy, segments 

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

 pjdicels very slender. Flixwecdi 



Waste places from Caithness southd., rarer in & -otland and Ireland ; a 

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



