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.