102 
IOWA ACADEMY OP SCIENCES. 
S. sericea Marsh, X cordata Muhl. Low ground, apparently 
frequent. S. sericea with serrate leaves. Not before reported 
in Iowa. 
S. cordata Muhl. Low ground, rare. 
S. cor data yivilal., X. sericea Low ground. Not before 
reported in Iowa. Mr. Bebb wrote that S. myricoides Muhl. is 
a synonym. Leaves nearly entire and a different plant from 
the second above. 
Populus tremuloides Michx. Woods, common. 
P. grardidentata Michx. Woods, common. 
P. monilifera Ait. Frequently coming up from seeds of 
planted trees. Dr. C. C. Parker feels sure that it occurs along 
our streams. If so, I have failed to notice it. 
CER ATOPH YLL ACE^ . 
Geratophyllum demersum L. Ponds infrequent. 
CONIFERS. 
Pinus strobus L. Woods, occasionally seen about Wadena. 
Juniperus communis L. Wooded hills along streams, common. 
J. virginiana L. At top of wooded bluffs, frequent. 
Taxus canadensis Willd. At the base of wooded bluffs, fre- 
quent. 
HYDROCHARIDACE^. 
Elodea canadensis Michx. Ponds, infrequent. 
Vallisneria spiralis L. In Volga river, rare. 
ORCHIDACEtE. 
Aplectrum hiemale Nutt. Woods, frequent. 
Spiranthes cernua Richard. Prairies, rare. Mr. J. R. 
Gardner, coll. 
Galopogon pulchellus R. Br. Prairies at Wadena, rare. 
Pogonia pendula Lindl. Rich woods, rooting in decayed 
wood and bloomirg in August or September, rare. 
Orchis spectahilis L. Woods, frequent. 
Habenaria tridentata 'Kook.. Prairies at Wadena, rare. First 
reported for Iowa by the writer. Proc. Iowa Acad. Sci., 1: 103, 
1893. 
H. bracteata R. Br. Woods, rare. 
H. liookeri Torr. Woods, rare. 
H. hookeriToTT.j var. oblongifoliaKdAne. Woods, rare. First 
reported for Iowa by the writer. Proc. Iowa Acad. Sci. , 1 : 103, 
1893. 
