PLANT STUDIES IN LYON COUNTY 
399 
much dissected, in strong contrast to related species growing in 
sheltered localities ( Viola pedatifida, Petalostemum candidum, 
Petalostemum purpureum and Anemone patens var. Wolfgangi- 
ana), or they have very well developed root systems ( Petaloste- 
mum candidum, Petalostemum purpurcum, Aster sericeus, 
Kuhnia eupatorioides var. corymbulosa, and Andropogon sco- 
parius) . Gummy secretions protect some, as in Grindellia 
squamosa and Helianthus scaberrimus , while others protect 
themselves by very narrow and convolute leaves ( Bouteloua cur- 
tipendula, Bouteloua hirsute, Andropogon scoparius and Andro- 
pogan fur cat us) . 
Of the plants found at Station IV, the high prairie, 19 per 
cent are found at Station I, the river flat. Thirty-two ‘per cent 
of the plants of the dry prairie, Station IV, extend down the 
upper north face of the bluff to Station III, and, 12 per cent 
get to Station II, the lower forest level on the north bluff face. 
Some of these are strays, as in the case of Cirsium iowense, and 
Oxalis stricta, whose home is on the high prairie, but a few speci- 
mens of which occur, perhaps accidentally introduced; others, 
as Melilotus alba, are naturalized plants found at all stations, 
though growing much more vigorously in the damp river-bottom 
soil than in the dry soil of the high prairie, while there are 
hardy natives, as Euphorbia marginata, which can endure the 
dry upland, but also flourish more luxuriantly on the river flat. 
Rudbeckia laciniata, found at all stations, we would expect at the 
protected stations, and look upon it as a stray on the high dry 
prairies. This plant, is unusual in Northwest Iowa. 
Fift}^ per cent of the flora of Station I is not found at any 
other station, and 83 per cent of it does not appear at Station IV, 
which is its greatest extreme as respects conditions in this local- 
ity. Seventy-six per cent of the plants found at Station I (river 
flat) do not appear at Station II (lower timbered bluff face), 
and seventy per cent of them at Station III (upper timbered bluff 
face). The difference between II and III in favor of III is to be 
accounted for by carriage of seeds by birds in the case of such 
plants as Vitis vulpina, Symphoricarpos occidentals, Sambucus 
canadensis, and Ribes Cynosbati, and to other accidents of local 
distribution in the case of Agastache nepet aides , Chenopodium 
hybridum, Euporbia marginata, Laportea canadensis, Polanasia 
trachysperma, TJlmus americana, and Vernon' a fasciculata. In the 
