Jan., 1922] UPHOF — PLANTS IN SOUTHEASTERN MISSOURI 
5 
although they occur also in other parts. In the southwestern part of Butler 
County and in the neighborhood of Poplar Bluff in the same county, several 
individuals were found of Vaccinium arboreum Marsh., of which the highest 
plant attained a height of 3^/2 rneters; the highest ones I met in this region 
grew in a scattered wood especially where Quercus marilandica, Q. macro- 
carpa, and Carya ovata were predominating trees in a sandy loam. 
In spring the woods are covered with several early flowering plants, 
being to a large extent bulb- or rootstock-bearing species ; whole areas form 
a dense association of Podophyllum peltatum L. where hardly anything else 
is able to find a place. Along other parts of such woods there are, either 
scattered or in small patches, Anemonella thalictroides (L.) Spach, Viola 
pedata L., Oxalis violacea L., and Hypoxis hirsuta (L.) Coville. These species 
are common where trees are less dense or in open parts of the woods, places 
which are very exposed to drought; but the rootstocks and bulbs of these 
species are well protected. The thick roots of Anemonella, containing 
reserve food, are surrounded by a tissue of cork; whereas the bulbs of Oxalis 
and Hypoxis are protected by a fibrous mass consisting of the remains of 
scales. Where the soil contains more moisture and humus, interesting 
growths of Claytonia virginica L., Delphinium tricorne Michx., and Viola 
palmata L. are to be noticed. The undergrowth of these woods and thickets 
is later, in the early summer, succeeded in the first place by large areas of 
Potentilla canadensis L. which are especially a feature of situations having 
a rather sandy subsoil. Where this species is not present the surface is prac- 
tically everywhere covered by Houstonia coerulea L. which flowers until 
midsummer. Elsewhere, however, plenty of space is given to other species, 
where all those mentioned with the exception of few Podophyllums and 
Potentilla are growing; to which may be further added Krigia Dandelion 
(L.) Nutt., Fragaria virginiana Duchesne, Geum canadense Jacq., and 
Erigeron vernus (L.) T. & G. With the exception of Fragaria these species 
practically never cover considerable areas, and therefore one cannot speak 
of a certain association. When woods are becoming somewhat exposed, 
such species as Monarda Bradburiana Beck, Silene virginica L., Sisyrinchium 
campestre Bicknell, and considerable areas of Antennaria plantaginifolia 
(L.) Rich, abound. 
Later in the year the early flowering species gradually disappear. Hous- 
tonia is to a large extent replaced by Stylo santhes biflora (L.) B.S.P., in 
other sections by Lechea minor L. or Cunila Mariana L. Pure stands of 
each of the latter may cover one hill after the other. At this time of the 
year (from July to September) long rainless intervals often have much 
influence on the vegetation of these hills, for which the above named species 
are well adapted. On very exposed slopes only very drought-resistant 
species are to be noticed, among which Euphorbia maculata L., Agave virginica 
L., Croton capitatus Michx., and C. monanthogynus Michx. are commonest. 
Where plant growth is to a certain extent protected by the shade of only a 
