Jan., 1922] UPHOF PLANTS IN SOUTHEASTERN MISSOURI 
9 
Where limestone outcrops occur along considerable areas in the moun- 
tains, Juniperus virginiana L. usually covers large parts and forms pure 
stands. In Iron County these conifers sometimes are very common, grow- 
ing toward the summits of the mountains and along the edges of the cliffs. 
Lower down, Celtis occidentalis L., Acer Negundo L., Amelanchier canadensis 
(L.) Medic, Fraxinus quadrangulata Michx., Moms rubra L., Quercus 
marilandica Muench., Q. Muhlenbergii Engelm., Diospyros virginiana L., 
Carya alba (L.) Koch, and, under these, the shrubs Cornus asperifolia Michx., 
Viburnum rufidulum Raf., and Hydrangea arborescens L. are always present. 
On treeless portions of such rock outcrops the plant growth is very much 
exposed to extreme heat and drought ; therefore the flora is often xerophytic 
or semi-xerophytic, except near dripping ledges and little springs; here 
Selaginella rupestris (L.) Link, Woodsia obtusa (Spreng.) Torr., Cystopteris 
fragilis (L.) Bernh., Aquilegia canadensis L., Solidago Drummondii T. & G., 
and Heuchera hispida Pursh are predominating; in places less rich in soil 
Pellaea atropurpurea (L.) Link and Cheilanthes Feci Moore usually are the 
commonest species; on rock outcrops, somewhat shaded, in Ripley County, 
the writer found many plants of Asplenium viride Huds. and Pellaea dealhata 
Car. and a few individuals of the southwestern Pellaea mucronata DC; on 
the highest elevations of such cliffs and bare mountain summits, Draba 
cuneifolia Nutt., D. brachycarpa Nutt., and Androsace occidentalis Pursh 
are prevalent. On flat places Astragalus distortus T. & C, and Scutellaria 
parvula Michx. are very common. Where the situation is shadowed by 
some tree or by rocks and is somewhat moist, but nevertheless stony and 
covered with very little soil, a dense association of Camptosorus rhizophyllus 
(L.) Link, the well-known walking fern, covers several rocks, growing from 
one stone to the other and in this way sometimes covering considerable 
areas. Between rocks, Cystopteris bulbif era (L.) Bernh., Notholaena dealbata 
(Pursh) Kunze, Woodsia obtusa (Spreng.) Torr., Polystichum acrostichoides 
(Michx.) Schott, Asplenium platyneuron (L.) Oakes, A. Bradleyi DC. 
Eaton (rare), Erigeron philadelphicus L., Arabis dentata T. & C, and 
Opuntia Rafinesquii Engelm. occur almost everywhere. 
Where the rocky aspect gradually disappears and more soil accumulation 
is to be seen, such species occur as Desmanthus illinoensis (Michx.) MacM., 
Schrankia uncinata Willd., Cassia Medsgeri Shafer, C. nictitans L., Agave 
virginica L., Cooperia Drummondii Herb., Eryngium yuccifolium Michx., 
Verbascum Thapsus h., Desmodium paniculatum (L.) DC, D. marilandicum 
(L.) DC, Psoralea tenuiflora Pursh, and practically all composites which 
are to be found in the above-described hills of the oak facies. 
The prairie flora is not here well represented; although sometimes 
barren, treeless areas appear several square kilometers in extent. They 
occur in almost any of the counties in the Ozarks as far as they were studied. 
The principal vegetation is composed of grasses, especially Agropyron 
spicatum Scribn., Bouteloua oligostachya (Nutt.) Torr., B. curtipendula 
