1921] PALMER, THE FOREST FLORA OF THE OZARK REGION 227 



habit, flowering in spring and ripening tlie fruit the same autumn. The 

 leaves are sometimes glaucous. It is common along small rocky streams 

 throughout most of the Ozark region, often growing in the dry shingle or 

 gravelly beds and spreading by root-shoots. 



Viburnum affine Bush. A low, slender shrub related to F. scabrellum 

 Chapm., found sparingly along rocky bluffs. 



Aescvlus glabra var. leucodermis Sarg. This variety of Buckeye is 

 common along many of the small streams of the Ozark region, where it is 

 often a slender shrub, becoming in richer, alluvial bottoms a small or 

 medium sized tree. It has been reported from southern Arkansas and 

 eastern Texas, beyond the limits of the Ozark uplift, but it is most abund- 

 ant in our area, where it probably originated, and from whence it has 



been disseminated. 



Crataegus. Of this prolific genus quite a number of species have been 

 described from the Ozark region; some of them are well marked and 

 pecuHar, but as so little is known at present of their range beyond the 

 type localities they will not be taken up here, but perhaps may be dis- 

 cussed in a subsequent paper. 



A list of the other hgneous plants of the Ozark region, not commonly 

 found in the coastal plain, is given below: 

 Salix cordata Muhh Hydrangea arborescens L. 



Salix longipes var. Wardii Hydrangea cinerea Small 



Schneid, Physocarpus intermedins Schneid. 



Juglans cinerea L. Gymnocladus dioica K. Koch 



Corylus americana L. Robinia Pseudoacacia L. 



Corylus rostrata Ait. Acacia angustissima var. hirta Robins. 



Quercus borealis var. maxima Cladrastis lutea K. Koch 



Ashe. Magnolia acuminata L. 



Celtis laevigata var. texana Sarg. Cotinus americanus Nutt. 



Celtis pumila var. georgiana Ilex laevigata A. Gray 



Sarg. Staphylea trifoliata L. 



Aristolochia tomentosa Sims Fraxinus quadrangulata Michx. 



Ribes missouriense Nutt, Sapindus Drummondii Hook. & Arn. 



Ribes odoratum Wendl. Vitis Linsecomii Buckl. 



Ribes Cynosbati L. Lonicera flava Sims 



It is evident that the majority of these are species of the southern 

 Appalachians and their foothills, a region rather remote from the Ozark 

 uplift and separated from it by the lowlands of the Mississippi valley; 

 but clearly their origin must be sought in that direction. Such plants 

 as Celtis laevigata texana. Acacia angustissima hirta, Sapindus Drum- 

 viondii and Vitis Linsecomii are as certainly southwestern in their present 

 distribution, and are found only on that side of the Ozark uplift. Sap- 

 indus and Acacia, however, have both also invaded the coastal plain as 

 far as western Louisiana; and another common southwestern tree, Bum- 

 elia lanuginosa, frequently found throughout the southern part of the 

 Ozark region, is even more widely distributed southward. 



