Enkele floristische en cytotaxonomische waarnemingen op Schiermonnikoog

Several species recorded in the Netherlands island of Schiermonnikoog are discussed. Cochlearia anglica L. found in the southern part of the island proved to be octoploid (2n = 48). The Netherlands material of 1 C. officinale L. ishexaploid (2n = 36) and cytologically and morphologically intermediate between the British C. officinale (tetraploid, 2n = 24) and C. anglica. The Ornithogalum umbellatum complex is represented by two taxa. Both the triploid O. umbellatum L. s.str. and the penta-/hexaploid O. divergens Bor. can be found near the village of Schiermqnnikoog; probably the plants are not indigenous there. Of Ranunculus ficaria L. only the subsp. bulbifer Lawalree was found. Stellaria graminea L. is mostly diploid (2n = 26) in the Netherlands and elsewhere in Europe. All plants from Schiermonnikoog, that were counted, proved to be tetraploid (2n = 52). No morphological differences between the two cytotypes could be found. Of Symphytum officinale L. only one population was discovered. The plants are tetraploid (2n = 48) and purple or white flowered. Veronica hederifolia L. occurs on the island in two forms, viz. the tetraploid V. sublobata Fiseh (2n = 36) and the hexaploid V. hedehfolia L. s.str. (211 = 54).