POLYGONACEOUS GENERA. 23 
flowers, one only in the axil of each bract of the spike, the per- 
sistent styles, and, more important than all else, the absence of 
that articulation at base of the leaf-blade which marks Podygo- 
num,—these are three generic characters, and I propose for the 
group generic rank under the name Duravia. The species as 
far as known have received specific names under Polygonum as 
follows: D. CALIFORNICA (Meisn. in DC., xiv. 100), BIDWELLIÆ, 
GREENEI (Wats. Am. Acad. xiv. 294, 295); of the same genus, 
apparently, is the large suffrutescent species D. BoLANDERI 
(Brewer ex Gray, Am. Acad. viii. 400). 
For the small assemblage of the convolvulaceous Polygoneex, 
long ago aptly denominated Climbing Buckwheat by country 
people—and surely less unreasonably reduced to Fagopyrum by 
pre-Linneans, than to Polygonum by Linnzus—lI indicated in 
the Flora Franciscana that the generic name is BILDERDYKIA, 
Dumortier. 
Į do not admire uncouth personal names in botany, and regret 
that Zinzarta, used by Mr. Small, has not priority. 
Dumortier, whose Florula Belgica is very scarce—and as im- 
portant for Polygonee in particular as it is rare—places these 
plants, where they truly seem to belong, next to Fagopyrum . 
and in his view the group has a better claim to the status of a 
genus, than either Bistorta or Persicaria, both of which remain 
with him but sections of Polygonum. 
Two species, B. Convolvulus and dumetorum are named by 
him. Some of the others that go with them are B. scANDENS 
(Linn, Sp. 522), crttnopis (Michx. Fl. i. 241), cristata (E. & 
G. Pl. Lindh, 51) and prerocarpa (Wall. Catal. n. 1690). 
The Japanese P. multiflorum, commonly associated with the 
above I have not seen; but the description reads as if it might, 
perhaps, constitute a generic type. 
During some sixteen centuries was PERSICARIA recognized 
universally as a genus distinct from Polygonum. Linnzus, the 
great father of confusion as to genera of plants, reduced the 
species to Polygonum ; but ever since there has been a succession 
of authors who have protested against this, and reasserted PER- 
