Cytotaxonomic studies in the genus Symphytum. I. Symphytum officinale L. in the Netherlands

The genus Symphytum contains about 25 species (Bucknall, 1913). In the Netherlands it is represented by one indigenous species, S. officinale L.; two others, S. asperum Lepech. and S. bulbosum Schimp., have been introduced but have not become established. S. officinale is a variable species. Keener (1863) described a segregate, S. uliginosum, which was reduced to subspecific rank by Nyman (1878): S. officinale L. ssp. uliginosum (Kern.) Nym. The differences between subspecies officinale and uliginosum are: in ssp. officinale the stems and leaves are more or less densely hispid, in ssp. uliginosum they are provided with small white deciduous prickles with tubercular base. Furthermore in the first-mentioned ssp. the upper stem-leaves are entirely decurrent but in the last named they are not or partially decurrent. There is also a difference in the colour of the flowers: white, yellowish, or dark purple in ssp. officinale, and red-purple or violet in ssp. uliginosum.