60 
IOWA ACADEMY OF SCIENCE 
BRASSICA (Tourn) L. 
439. Brassica arvensis (L) Ktze. Charlock. Not uncommon in waste 
places. 
440. Brassica nigra (L) Koch. Black Mustard. A common weed. 
441. Brassica alba (L) Boiss. White Mustard. Rare; along railway, 
Iowa City. 
442. Brassica juncea (L) Cc-ss. Indian Mustard. Not uncommon as 
a roadside weed. 
SISYMBRIUM (Tourn) L. 
443. Sisymbrium officinale (L) Scop. Hedge Mustard. A common 
weed of waste places. 
444. Sisymbrium altissimum L. Tumbling Mustard. Common in 
roadsides and waste places. 
445. Sisymbrium canescens Nutt. Tansy Mustard. Common in sandy 
soils. 
446. Sisymbrium canescens Var. incisum Engelm. Tansy Mustard. 
With the above. 
HESPERIS (Tourn) L. 
447. Hesperis matron alis L. Dame’s Violet. Occasional. 
ERYSIMUM (Tourn) L. 
448. Erysimum ckeirantlioides L. Worm-Seed Mustard. Not uncom- 
mon in thickets. 
RADICULA (Dill) Hill. 
449. Badicula nasiurtium-aquaticum (L) Britt. & Rendle. True Water 
Cress. Common in springs, hogs. 
450. Radicida sessiliflora (Nutt) Gr. Sessile-flowered Cress. Not un- 
common along streams. 
451. Badicula obtusa (Nutt) Gr. Blunt-leaved Yellow Cress. With 
the above. 
452. Radicida obtusa Var. sphaerocarpa (Gray) Rob. Scarce in simi- 
lar places.. 
453. Radicida palustris (L) Moench. Marsh or Yellow Cress. Com- 
mon in moist soils. 
454. Radicida palustris Var. hispida (Desv) Bob. With the above 
but scarce. 
