MUSTARD FAMILY 279 



8. Rorippa Armoracia (L.) A. S. Hitchcock. Horseradish. Fig. 2029. 



Cochlearia Armoracia L. Sp. PI. 648. 1753. 



Nasturtium Armoracia Fries ex A. Gray, Man. ed. 2. 31. 1856. 



Rorippa Armoracia A. S. Hitchcock, Spring Fl. Manhattan 18. 1894. 



Radicula Armoracia Robinson, Rhodora 10: 32. 1908. 



Armoracia Armoracia Britt. in Britt. & Brown, 111. Fl. ed. 2. 2: 163. 1913. 



Stems erect, 6-10 dm. high, from deep thick roots. Basal leaves 15-30 cm. long oblong, 

 crenate or serrate or sometimes pinnatifid, rough but glabrous, on stout petioles ; stem leaves 

 sessile, smaller; racemes paniculate; pedicels very slender, 4-6 mm. long, ascending; flowers 

 white, showy, 4-8 mm. broad. 



Escaped from gardens in moist places, especially in Washington and Oregon, adventive from Europe. May- 

 July. 



Rorippa austriaca (Crantz) Spach, Hist. Veg. 6: 513. 1838. {Radicula austriaca Jepson, Fl. Calif. 

 2: 54. 1936.) Erect annual, 3-6 dm. high, puberulent. Leaves 3-6 cm. long, oblong-obovate, narrowed to 

 the auriculate base, unequally serrate, glabrous; racemes paniculate at the summit, 7-15 cm. long; petals yellow, 

 4 mm. long; fruiting pedicels spreading, 4-10 mm. long; pods 2-3 mm. long and nearly as broad. Reported 

 as a weed in cultivated fields in Modoc County, California (M. K. Bellue, Mo. Bull. Calif. Dept. Agr. 22: 385. 

 1933). Native of Austria. 



27. CARDAMINE [Tourn.] L. Sp. PI. 654. 1753. 



Annual or perennial herbs, with entire, lobed or divided leaves, and white or purple 

 flowers in racemes or corymbs. Stamens 6, rarely 4. Pod elongated, compressed parallel 

 with the partition; valves nerveless, elastically dehiscent. Seeds in 1 row in each cell, 

 wingless ; cotyledons accumbent. [Name Greek, meaning heart-strengthening, an ancient 

 name for some cress supposed to have that quality.] 



A genus of about 125 species, natives of the temperate regions. Type species, Cardamine pratensis L. 



Leaves all simple. 



Leaves ovate or elliptical, entire; dwarf plants. 1. C. bellidifolia. 



Leaves cordate or reniform, sinuate; stems 2-6 dm. high. 2. C. Lyallii. 



Leaves, at least those of the stem, compound. 



Basal leaves simple; stem leaves 3-5-foliolate. 3. C. Breweri. 



Basal leaves pinnate. 



Leaves 3-foliolate, rarely 5-foliolate; leaflets 3-lobed or 3-toothed; petals 8-12 mm. long. 



4. C. angulata. 

 Leaves 5-1 5-foliolate, or the basal sometimes 3-foliolate. 

 Perennials with rootstocks. 



Petals 5-6 mm. long. 5. C. Gambellii. 



Petals 2-4 mm. long. 



Racemes elongated. 6. C. occidentalis. 



Racemes subumbellate. 7. C. umbellata. 



Annuals. 



Petals 6 mm. long, rose-purple. 8. C. Pattersonii. 



Petals 2-3 mm. long, white. 



Pod 20-30-seeded; leaflets oblong or linear. 9. C. Pennsylvania. 



Pod 8-20-seeded; leaflets mostly rounded. 10. C. oligosperma. 



1. Cardamine bellidifolia L. Alpine Bitter-cress. Fig. 2030. 



Cardamine bellidifolia L. Sp. PI. 654. 1753. 



Cardamine bellidifolia var. pachyphylla Leiberg, Proc. Biol. Soc. Wash. 11: 170. 1897. 



Glabrous perennial, tufted from a branched caudex, the roots fibrous, the stems 3-10 cm. 

 high. Leaves long-petioled, ovate, 10-15 mm. long, entire or with 1 or 2 lateral teeth ; flowers 

 1-5 ; petals white, spatulate, 3-4 mm. long ; pods erect, linear, 2-4 cm. long, 2 mm. wide ; style 

 stout, about 1 mm. long. 



Arctic- Alpine species; Alaska south to Mount Adams, Washington, Crater Lake, Oregon, and Mount Shasta 

 and Mount Lassen, California, east to Greenland and the White Mountains, New Hampshire; also in Europe 

 and Asia. July. 



2. Cardamine Lyallii S. Wats. Lyall's Bitter-cress. Fig. 2031. 



Cardamine Lyallii S. Wats. Proc. Amer. Acad. 22: 466. 1887. 

 Cardamine Lyallii var. pilosa O. E. Schulz, Bot. Jahrb. 32: 438. 1903. 

 Cardamine cordifolia var. Lyallii A. Nels. & Macbr. Bot. Gaz. 61: 31. 1916. 



Plants glabrous or sparsely pilose, the stems erect from a running rootstock, 2-6 dm. high, 

 simple or branched. Leaves 4-8, petiolate, cordate to reniform, 2.5-7.5 cm. long, entire or shal- 

 lowly sinuate ; pedicels spreading ; petals white ; pods erect, 2-4 cm. long, shortly attenuate ; 

 style very short. 



Montane, Hudsonian and Canadian Zones; Cascade Mountains, southern British Columbia, to Placer 

 County, California, east to_ the Blue Mountains, Oregon, and northern Nevada. Type locality: "Banks of the 

 Ashtnola, Cascade Mountains." July-Aug. 



3. Cardamine Breweri S. Wats. Brewer's Bitter-cress. Fig. 2032. 



Cardamine Breweri S. Wats. Proc. Amer. Acad. 10: 339. 1875. 

 Cardamine orbicularis Greene, Pittonia 4: 202. 1901. 



Plants perennial from slender rootstocks, glabrous or slightly pubescent, the stems erect or 



