Rorippa Rorippa, (Heuffel) Neilr.

6. R. prolifera (Heuffel) Neilr. , Aufz. Ung. Slav. Gefäss. 263 (1866).

Annual or biennial 40-60 cm. Leaves pinnate with 2- 4

pairs of oblong-lanceolate segments which are coarsely toothed to entire. Racemes short, branched, numerous, forming a corymb. Petals 3 mm, equalling or slightly exceeding calyx. Siliqua 3-8 mm, linear or oblong-linear, about half as long as the pedicel; style about | as long as the siliqua. Balkan peninsula, Romania. Al Bu G r Ju Rm. In addition to 3, at least ten other hybrids involving 1-6 have been recorded from Europe, and some are treated as species in Floras; their nomenclature is extensive and confused. Probably the most important are R. x astyla (Reichenb.) Reichenb. ( R. islandica x sylvestris ), and R. x armoracioides (Tausch) Fuss ( R. austriaca x sylvestris ). Both are generally intermediate between the parents and reduced fertility is sometimes evident, though the fact that in both cases specimens resembling more strongly one or other of the parents are recorded suggests that the hybrids are partially fertile. A thorough investigation of these and other Rorippa hybrids is much needed.