306 IOWA ACADEMY OF SCIENCE Vol. XXVI, 1919 



VARIATIONS IN ROSA PRATIJ^^COLA 

 Sepals 



Position. — In the schemes of classification made for roses much 

 stress is laid upon the position of the sepals on the mature fruit, 

 whether connivent and persistent, or spreading and deciduous. No 

 uniformity was found in the specimens of R. prafincola. In one 

 group of these roses that grew along a roadside in Dickinson 

 county, a part had spreading sepals and a few combined the two 

 types. In regard to the other characters, viz., leaves, pedicels, stem, 

 etc., there was sufficient uniformity to satisfy one that there were 

 not two species and a hybrid. In this same general locality there 

 was another group in which all the plants save one had connivent 

 sepals. It can be said, however, that the greater proportion of 

 the plants have connivent sepals. 



Surface of the basal part. — Out of the 250 specimens examined 

 the majority have glandular-hispid and pubescent surfaces. A small 

 per cent of the surfaces are glandular-pubescent, a few are pubes- 

 cent and occasionally naked ones are found. 



Foliaccoiis Tips. — The outer extremities of the sepals are more or 

 less dilated. These are quite variable in length, ranging from two 

 to fifteen mm. Only a very small per cent are lobed though in 

 Gray's manual one of the taxonomic characters is "outer sepals 

 lobed." 



Stem 



Height. — The smallest plant found in bloom was thirteen cm. in 

 height while the tallest plants average about seventy-five cm. 



Surface. — The greater percentage of the stems can be classed 

 as prickly or very prickly. Most of the prickles are small with 

 larger spines intermingled. The prickles may be weak or stiff 

 and harsh. It is a common occurrence to find one stem with 

 deciduous prickles among a group of prickly forms. 



The upper portion of the stem may be unarmed. Specimens 

 were collected the upper part of whose stems are free from spines 

 of any kind, while the basal portions are covered with a flaky 

 epidermis and there are a few spines about one mm. long. The 

 prickles may be few but scattered along the whole length of the 

 stem. In addition to prickles there may be stipitate glands. The 

 climax of variability seemed to be reached when stems free from 

 prickles of any description were found. 



Branches. — The young stem very seldom branches but the older 

 stems are usually much-branched. No difference was found in the 



