238 IOWA ACADEMY OF SCIENCES. 



GENTIANACE^. 



Gentiana L. Gentian. 

 411). G. detousa Rottb. Collected but once in low 

 ground near Armstrong. 



420. G. qiiuH/Hcfolia (K-cidentalis (A. Gray) Hitchcock. 



Rare in woods near Estherville. 



421. G. puhendd Michx. Frequent on rather high prai- 



ries. 



422. G. andrewsii Griseb. Low ground; our common- 



est species. 



MENYANTHACE.^. 



Menyanthes L. Buck Bean. 



423. M. trifoliafa L. Frequent in bogs. 



APOCYNACE^. 



Apocynum L. Dogbane. 



424. A. aHdros(vmifolium L. Common in woods; 



branches widely spreading. 



425. A. cannahinum L. Common in woods and on low 



prairies. 



ASCLEPIADACE^. 

 ASCLEPIAS L. 



426. A. tuherosa L. Pleurisy-root. Common on dry 



prairies. 



427. A. hicarmda L. Swamp Milkweed. Common in 



low ground. 



428. A. sulliraniii Engelm. Frequent on low prairies. 



429. ^4. syriaca L. (.4. cormdi L.) Common Milkweed 



or Silkweed. Common near woods. 



430. A. speciosa Torr. Showy Milkweed. Common on 



prairies, where it takes the place of the preced- 

 ing species which has much smaller flowers. 



431. A. ovalifolia Decaisne. Dry woods and prairies; 



frequent. 



