PLANTS OF IOWA 189 



2444. E. untans, Lag. Upright Spurge. 

 A common weed. 



2445. E. corollata, L. Flowering Spurge. 

 Common in dry, open places. 



2446. E. marginata, Pursh. White-margined Spurge. 

 In dry soil, escaped from cultivation. 



2447. E. dentata, Michx. Toothed Spurge. 

 Common in sandy soil. 



2448. E. heterophylla, L. Various-leaved Spurge. 

 Common in sandy soil. 



2449. E. obtusata, Pursh. Blunt-leaved Spurge. 

 Infrequent, sandy soil. 



2450. E. missouriensis, (Norton) Small. Reticulate-seeded 



Spurge. 

 Not common. 



2451. E. peplus, L. Petty Spurge. 

 In waste places, from Europe. 



2452. E. commutata, Engelm. Tinted Spurge. 

 Not common. 



2453. E. cyparissias, L. Cypress Spurge. 

 From gardens, infrequent. 



CALLITEIFHACE.E. WATEE-STAEWORT FAMILY. 



CALLITRICHE, L. 



2454. C. paustris, L. Vernal Water-starwort. 

 Not common. 



ANACAE^ICE.ffi. SUMAC FAMILY. 



RHUS, L. 



2455. E. hirta, (L.) Sudw. Staghorn Sumac. 

 Common, on rocky slopes. 



2456. E. glabra, L. Smooth Sumac. 



Very common in thickets and along borders, chiefly in 

 dry places. 



2457. E. aromatica, Ait. Sweet-scented Sumac. 

 Frequent. 



2458. E. radicans, L. Poison Ivy. 



Common along borders, and in low grounds. 



