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Symphytum tuberosum L., Tuberous Comfrey

Account Summary

Introduction, neophyte, a very rare garden escape or discard, presumed locally extinct.

1951; MCM & D; riverbank near Pollboy Bridge, Colebrooke River.

Like the hybrid Russian Comfrey, the single Fermanagh occurrence of this rhizomatous, hispid perennial species 20-50 cm tall, found by Meikle and friends is derived from material of garden origin dumped in a rural riverbank situation. It flowers in June and July, the corolla is a pale creamy yellow and the calyx is more deeply divided than that of the other two much more frequent, taller Comfreys in the VC, the lobes being free for at least three-quarters of the way towards the base (An Irish Flora 1996). It is also distinguished from S. officinale by its lower stature, scarcely-branching habit and the middle stem-leaves, not the lowest, being the largest (Garrard & Streeter 1983).

There is just the one record in Fermanagh as listed above. S. tuberosum has not been seen in the VC for more than 70 years and is, therefore, presumed to be locally extinct. The species has a similar status elsewhere in Ireland, where it has been recorded as an occasional garden escape or relict of cultivation in open, disturbed habitats such as roadsides, hedge-banks, woodland margins or clearings, plus on waste ground and in quarries along with obviously dumped material. The Cat Alien Pl Ir lists S. tuberosum as having occurred at least once in thirteen Irish VCs, not counting Fermanagh. The FNEI 3 lists S. tuberosum as having naturalised and persisted at two sites in Co Down (H38): for at least 33 years at Conlig, and 81 years in the Clandeboye estate woods.

The survival and local increase of this perfectly hardy species anywhere in B & I is almost certainly chiefly the result of vegetative growth of its creeping rhizome, rather than seed production, since there does not appear to be evidence of jump dispersal. There are, however, rare reports of large, dominant patches probably developing over several decades in parts of S England, for instance in S Hants (VC 11) (Brewis et al. 1996).

The New Atlas map for Ireland plots a total of 21 hectads with the most recent date class (1987-1999) having at least one record. The hectads are rather scattered but are somewhat more concentrated the NE of the country and, in a general manner, in the northern half of the island.

Again, as the New Atlas indicates, the occurrence of S. tuberosum in Britain is very much more frequent and widespread than in Ireland. This is especially so in lowland Scotland from Glasgow and Edinburgh north to Aberdeen and Inverness. This particular swathe of Scottish records is plotted as if the species is native, whereas, elsewhere in Scotland, S. tuberosum is considered alien, appearing thinly scattered and becoming more coastal in the W and the far NE of the country. In its supposed native range, Tuberous Comfrey occurs in damp woods, riverbanks and ditches. In England and Wales, south of a line between Morecambe and Alnwick, S. tuberosum is thinly and widely scattered, and, again, is considered an alien garden escape or discard. It the regions where it is considered alien, S. tuberosum grows mainly in disturbed, open, artificial habitats such as roadside verges and waste places (D. Welch, in: Preston et al. 2002).

Beyond B & I, S. tuberosum belongs to the European temperate phytogeographical element and occurs in W, C & S Europe and NW Anatolia (Sell & Murrell 2009)

Threats

None.