432 
Nanthoxylum americanum Mill. Prick- 
ly ash was seen in Balk prairie, where it 
was growing in loess. The woodlands ad- 
joining many other prairies contained this 
species ; only at Balk had it strayed into the 
prairie. 
POLYGALACEAE 
Polygala incarnata L. This milkwort 
was found in loess on the crest of the 
ridge at Northeast Meredosia. 
Polygala verticillata L. This species, 
easily overlooked in its location between 
tufts of grass, was observed in nine prai- 
ries from Fountain Bluff northward. 
EUPHORBIACEAE 
Acalypha gracilens Gray. This three- 
seeded mercury grew on the rocky prairie 
slopes and sandstone ledges at Fountain 
Bluff. 
Chamaesyce glyptosperma (Engelm.) 
Small. [Euphorbia glyptosperma En- 
gelm.] This plant was found in rock 
prairie at Devil’s Backbone. 
Chamaesyce maculata (L.) Small. 
[Euphorbia maculata L.| Nodding spurge 
was seen in 14 hill prairies; in none of 
them was it abundant. 
Chamaesyce supina (Raf.) Moldenke. 
[Euphorbia supina Raf.] Milk-purslane 
was found between the bunches of grass 
in six hill prairies. It was observed also 
in crevices of ledges. 
Croton capitatus Michx. Hogwort was 
found only at Principia and Edgemont. 
Croton glandulosus var. septentrionalis 
Muell. Arg. Sand croton was found only 
at Bluff Springs and Block House. 
Croton monanthogynus Michx. Prai- 
rie-tea, a frequently encountered plant in 
hill prairie, was observed at 19 sites in 
central and southern [llinois. 
Euphorbia corollata L. Flowering 
spurge, a common plant in prairies, glades, 
and rocky ground, was found in 36 hill 
prairies, where it grew in loess and rocky 
soil. It was found also in some adjacent 
woodlands. 
*Euphorbia cyparissias L.  Cypress- 
spurge, or cemetery cypress, was found 
in the Seehorn-Payson prairie as an escape 
from a nearby cemetery. 
Euphorbia obtusata Pursh. 
cies was collected at Fults. 
This spe- 
Ittinors NaturRAL History SurvEY BULLETIN 
Vol. 26, Art. 5 
Poinsettia dentata (Michx.) Small. 
[Euphorbia dentata Michx.] This weedy 
species was found in 15 hill prairies. 
ANACARDIACEAE 
Rhus aromatica Ait. Fragrant sumac 
was seen in 15 hill prairies, either in loess 
or rocky soil. It was encountered also in — 
some wooded coves as well as in bluff-top_ 
woods. 
Rhus aromatica var. arenaria (Greene) _ 
Fern. This variety of the fragrant sumac 
was found in sandy loess at Bald Bluff, 
Balk, Bielema, and South Palisades. 
Rhus copallina L. Shining or dwarf 
sumac was found in loess at Southwest 
Edgemont, Chalfin Bridge, Fults, and 
Phegley. i 
Rhus glabra L. Smooth sumac was a ~ 
very frequent plant in the hill prairies — 
studied. It was observed on 33 rock and~ 
loess prairie slopes. It grew in coves and _ 
extended out on the spurs, or it grew in the ~ 
borders of the bluff-top woods and out in 
the prairies as isolated individuals. In 
some places it was very dense and formed 
a thicket. In a few other places most of 
the individuals in open groups were dead 
or dying, a result possibly of fire, or of 
competition by grasses, competition in- 
tensified by summer drought. 
Rhus radicans L. Poison ivy, erro- 
neously called poison oak, was very abun- 
dant in woodlands adjacent to most of the 
hill prairies. It was found at Principia 
in loess and rock prairie. . 
AQUIFOLIACEAE 
Ilex decidua Walt. Possumhaw or 
swamp holly, normally found in bottom- 
land woods or on basal slopes of bluffs 
infrequently on shaded cliffs, was ob- 
served in a cove at Phegley, 200 feet 
above the adjacent bottomland. 
CCELASTRACEAE 
Celastrus scandens L. Bittersweet oc- 
curred in eight hill prairies that adjoined 
woods. It occurred also in wooded cove 
near prairie. 
RHAMNACEAE 
Ceanothus americanus L. New Jerse} 
tea, a plant of rocky woods, forest bor 
ders, and glades, was observed in 12 loes 
