Salix purpurea × S. viminalis (S.
× rubra Huds.), Green-leaved Willow
Account Summary
Introduced, archaeophyte, rare, but very possibly under-recorded and perhaps occasional. Eurosiberian southern-temperate, but also naturalised.
1949; MCM & D; roadside near Drumrain [sic, ie Drumram] Lough, SW of Donagh Crossroads.
According to Meikle (1984), this is one of the more common Salix hybrids "found here and there throughout the British Isles". One might add, 'indeed across almost all of Europe'. The main reason for this is that it was once a popular cane-providing shrub with basket makers, grown in osier-beds in a wide variety of clonally reproduced cultivars. Despite this fact it is said to vary within a narrow compass and appears intermediate between its parent species.
All four records of the hybrid in the Fermanagh Flora Database are pre-1975 and were made by Meikle himself and his co-workers. Thus we, and all the other field workers in Fermanagh since 1953, appear to be completely overlooking this hybrid. Apart from the first record above, the remaining details are: Drumkeenagh, Black River, ie at NW end of Upper Lough Macnean, 1950; streamside, upper part of Donaghmore Glen, S of Cooneen, 1950; Many Burns River, N of Many Burns Bridge, 1953.
The few habitats we have evidence of are not unusually associated with damp or wet ground on roadsides, near lakeshores and by river and stream banks. However, this suggests to us rare spontaneous crosses arise in open, more or less competition-free ground, with or without the parent species, probably in naturalised thickets rather than in previously cultivated ground. Having said that, all but three types of spontaneous willow hybrids are occasional to rare or very rare, and S. × rubra is merely one of the occasional ones (R.D. Meikle, in: Stace 1975, p. 305). The possibility of some of these stations representing the margins of old osier plantations cannot be definitely decided upon at this remove, but no comment claiming this is made in either version of the MCM & D Typescript Flora (1957, 1975).
For comparison, the FNEI 3 gives brief details of a total of 14 stations in the three counties it covers, spanning the whole period from John Templeton (active 1793-1825) until 1990. The very thinly scattered recorded occurrence displayed for this hybrid in the New Atlas hectad map (in Ireland largely confined to northern counties), suggests to the current author that either Meikle over-estimated the extent of this hybrid, or else it is frequently overlooked in both B & I.
Growth form and preferred habitats
The linear-oblong leaves, and the associated buds and branches are very unusual and distinctive for a willow in being borne opposite or sub-opposite, rather than in the alternate and spiral arrangement more typical of the genus. Although the specific epithet is 'purpurea' and the English common name a translation, 'Purple Willow', in reality the twigs are usually yellow or grey, only sometimes tinged with purple or red.
In the Typescript Flora and Revised Typescript Flora, Meikle et al. (1957, 1975) considered this variable shrubby species to be frequent in marshy ground and waterside banks in Fermanagh. They commented that it was often planted along with other suitable, but more decidedly alien Salix species, such as S. viminalis (Osier) and S. triandra (Almond Willow), in wet parts of lowland farms (ie 'sally gardens'). Stems were harvested both as basket canes, or withies and for thicker, lightweight timbers, which were put to a great variety of uses described in farming folk literature (Evans 1942, 1957). Uses included live material for rapid screening and as shelter for livestock, or in some species for animal fodder. S. purpurea is an exception in this last case, being much too sharp-tasting, even for rabbits and hares (Newsholme 1992). S. purpurea produces a woodier, tougher rod than S. viminalis and thinner rods of it are also more pliable than the latter when fresh or partially dried (Hogan 2001).
Fermanagh occurrences
Meikle and his co-workers (1975) noted that in Fermanagh S. purpurea also grew spontaneously and apparently indigenously on wet hillsides, occasionally remote from habitation, eg in hedgerows, beside streams and in damp hollows in the uplands. In the immediate post-war period, when they were recording, S. purpurea was particularly frequent around the Carnmore area, between Lisnaskea and Rosslea in the E of Fermanagh. Our longer term survey has recorded S. purpurea in a total of 63 tetrads, representing 11.9% of those squares in the VC. As the tetrad map shows this shrub is very widely scattered throughout, but with a slight concentration of records in the more actively farmed lowland SE of the county. The fact that there are 19 tetrads with only pre-1976 records suggests there has been a loss of suitable habitat, or competitive ousting has taken place.
British and Irish occurrence
The New Atlas hectad map shows that S. purpurea is fairly common and widespread throughout B & I, although the distribution really is rather patchy. Furthermore, since this species was much planted in the past we really cannot discriminate native occurrences.
In Ireland, the hectad map suggests it is much more prevalent in NI and in the Midlands, ie across the country from E Mayo to Kildare (H26-H19). The Cen Cat Fl Ir 2 suggests the status of this species is, "possibly introduced", with the additional debatable comment considering it, "probably native in the Centre". Further S & W in Ireland, S. purpurea is either very much more scattered or virtually absent.
Typical wet ground habitats in Britain include woodland margins, shingle beside rivers and streams and in marshes and fens, including osier beds (G. Hutchinson, in: Preston et al. 2002). The distribution in Britain is curiously concentrated along the spine or middle regions, becoming less prevalent to both east and west of the central line as far north as the Scottish Highlands. North of Glasgow and Edinburgh it becomes much more scarce and coastal, although reaching one isolated hexad in Shetland, a distribution suggesting a temperature limitation is in force.
The map of the European distribution suggests that in B & I, S. purpurea is only indigenous in N England, S Scotland and NW and C Ireland (Jalas & Suominen 1976, Map 255). Meikle (1984) suggests S. purpurea has a much greater claim to be indigenous than either S. viminalis or S. triandra, and the current author would not argue with that expert assessment. With regard to native occurrence, it is significant that occasionally S. purpurea grows in damp hillside and streamside sites quite remote from both habitation and cultivation, where it presumably must have self-sown (Meikle 1984).
From the published hectad maps, there appears to have been little or no change in the S. purpurea distribution during the 40 years between the two B & I flora atlases (Perring & Walters 1976; Preston et al. 2002) − a rather surprising finding in view of the considerable loss of wetland habitats due to drainage and herbicide use associated with the intensification of farming during this period.
European and world occurrence
The suggestion of a temperature limit to distribution is confirmed by an examination of the European range of the shrub which thins markedly beyond 55°N; it scarcely passes anywhere beyond 60°N, and is plotted as 'introduced' in most of such areas. It is therefore more or less absent from Scandinavia, and it is also so from much of C Europe. Several closely related species occur in Asia (Meikle 1984; Jalas & Suominen 1976, Map 255).
Threats
None.