Zs. P. Komáromy szerk.: Studia Botanica Hungarica 12. 1977 (Budapest, 1977)

Radics, Ferenc: The identification of Rorippa species and hybrids (Cruciferae) based on external morphological features of their seeds

Characteristic morphological features of seeds of the basic Rorippa species Rorippa amphibia (L. ) BESS. (Plate I, 1-2) Length: 1 to 1.2 mm. Shape: ellipsoid or oval, rather pointed on both ends, at the arched, opposite to hilum truncate, Sclerotic layer of seed coat (testa), when seen from above, reticulated, with dimples. Epidermis cells are less transparent and as their horizontal extension is bigger than that of cells below them, presenting thickened walls in U-shape, they are mostly ruffled and adhere to latter, especially when dry. Colour: brown. Radicle (radicula): accumbent to cotyledons. Rorippa austriaca (CR. ) BESS. (Plate I, 3-4) Length: 0. 7 to 0. 8 mm. Shape: rounded or angular, near hilum horizontally cut off (truncate), opposite to hilum, however, it appears to be cuspidate. Horizontal extension of cells of sclerotic layer is among all Rorippa species the largest. This layer is hardly visible because the epidermis cells are granulated by oil like globules, consequently seed surface entirely granulated, Side walls of sclerotic cells are thiner than other Rorippa species belonging here. Thus, common side wall of every two cells, when looking at edge of seeds forms an acute angle. Colour: yellowish brown. Radicle: accumbent. Rorippa palustris (L. ) BESS. (Plate I, 5-6) According to JONSELL (1968) and TOMSOVIC (1969) this is the correct name of this taxon. Length: 0. 6 to 0. 7 mm. Shape: obovate. Near hilum, obliquely cut off, opposite to hilum pointed, cuspidate. Pattern of sclerotic laver likewise reticulated, with dimples, but meshes of network - excepting Rorippa proliféra - a less extension than those of other basic species. This network on the seeds of basic species, view from above, is hardly perceptible owing to the slime content of the dotted epidermis cells, seed surface appears to have a velvety surface. Colour: darker brown. Radicle (radicula): accumbent.