Hybridism and Classification in the Genus Rosa. 159 
TABLE I. 
Section I. Synstyl^e. 
Group of Rosa arvensis Huds. (1762). 
Section II. Stylos^e. 
Group of Rosa stylosa Desv. (1809). 
Section III. Canin/E. 
Sub-sect. Eu-caninse. 
Group of Rosa canina Linn. (1753). 
„ „ dumetorum Thuill. (1799). 
„ „ glauca Vill. (1809). 
„ „ coviifolia Fries (1814). 
,, „ subcanina Chr. (1873). 
,, „ subcollina Chr. (1873). 
„ „ tomentella Lem. (1818). 
Subsect. Rubiginosae. 
Group of Rosa Eglanteria Linn. (1753). 
„ „ micrantha Sm. (1812). 
„ „ agrestis Savi (1798). 
Subsect. Villosae. 
Group of Rosa villosa Linn. (1753). 
„ „ tomentosa Sm. (1800). 
Section IV. Pimpinellifolle. 
Group of Rosa pimpinellifolia Linn. (1753). 
Section V. Pimpinellifolle HybriD/E. 
Group of Rosa involuta Sm. 
( R . pimpinellifolia agg. x tomentosa agg.) 
Group of Rosa hibernica Tempi. 
(R. pimpinellifolia agg. x Eu-canince). 
Group of R. bitungensis Bor. 
(R. pimpinellifolia agg. x rubiginosa agg.) 
general sense only) may be distinguished according to leaf-serration 
and the nature of the peduncles. To take these two characters 
only, (1) Biserrate leaflets (B), not biserrate (b), (2) Hispid, 
glandular or setose peduncles (S), smooth peduncles (s), the 
following four theoretical combinations may be expected—BS, Bs, 
bS, and bs. R. arvensis Huds. is a bS form and the smooth 
peduncled form bs is R. erronea Rip. The combination BS 
corresponds to var. biserrata Cr^p. This analysis does not include 
R. ovata Lej. which is simply a narrow-fruited variety of the type, 
nor R. gallicoides Des^gl. a fairly well-marked form owing to the 
admixture of acicles on the upper part of the stems, a feature which 
