Adventieve Biscutella’s

Two species of Biscutella, viz. B. auriculata L. and B. didyma L. are known as aliens in the Netherlands. They can be distinguished from each other as follows: 1. Petals c. 10—15 mm long, with a long claw. Outer sepals saccate at the base. Silicula not emarginate at the apex, but narrowed into the style .............. 1. B. auriculata L. 1’. Petals c. 3—5 mm long, with a very short claw. Outer sepals not saccate. Silicula emarginate at the apex .............................. 2. B. didyma L. Of B. didyma both var. leiocarpa (DC.) Halacsy (glabrous fruits) and var. ciliata (DC.) Halacsy (fruits with ciliate margins and sometimes with short hairs on the valves) have been found.