Salix viminalis × S. cinerea (S.
× holosericea Willd. = S. × smithiana
auct., nonWilld.), Silky-leaved Osier

Both spontaneous and an introduced and deliberately planted archaeophyte, rare, but very probably over-looked and under-recorded.

1948; MCM & D; Lough Aguse, Tullygerravra Td, 6 km SE of Garrison.

July and October.

This is regarded by Meikle (1984) as one of the more common Salix hybrids in B & I, but as he also points out, it is an easy one to confuse with S. caprea × S. viminalis (S. × sericans) (Broad-leaved Osier). There are only eight records of S. × holosericea in the Fermanagh Flora Database and all but two date from the 1948-53 period and were made by Meikle and his co-workers. Apart from the first record given above, the remaining details are: near Kesh, 1950; Roogagh River near Tullynanny Lough, 1950; Ross Lough near Carr Bridge, 1950; Mullyduff Lake, E of Newtownbutler, 1951; roadside between Ballindarragh and Lough Digh, 1953; Goladoo disused quarry, 20 October 1996, RHN, det. P. Hackney, Herb. RHN; upstream of bridge, near Rosscor viaduct, 2 November 2010, Herb. RHN.

Thus in Fermanagh, S. × holosericea is extremely thinly and widely scattered in damp or wet habitats on lakeshores, river banks and roadsides.

In the Flora of Lough Neagh, this willow hybrid is regarded as locally frequent in hedgebanks, ditches, streams and lakeshore thickets and it is mapped in 17 tetrads around the lakeshore. The FNEI 3 account also describes the shrub as "frequent", although the number of sites listed for the three component VCs (including some very old 19th century records) amounts to a total of just 50.

S. viminalis (Osier) was introduced in ancient times and widely and commonly cultivated throughout B & I for basket cane production. Both the above mentioned osier hybrids involving this introduction can arise spontaneously through its ready interbreeding with large and widespread native populations of S. cinerea subsp. oleifolia (Rusty Willow) in this instance, and similarly with S. caprea (Goat Willow) to create S. × sericans (Broad-leaved Osier). Clones of both these hybrids were also commercially propagated and around a century ago were widely used for basket canes. Very probably some of the hybrids found nowadays are the outcome of rarely occurring indigenous local crossings, but certainly the majority of them are relicts of cultivation.

The map of S. × holosericea in the New Atlas shows a large majority of its Irish records are confined to NI. However, as the brief species account accompanying the map suggests, this hybrid is very probably under-recorded throughout B & I (G. Hutchinson, in: Preston et al. 2002). In the current author's view, the same can be said of all willow hybrids and, indeed, of some willow species too. In recent years there has been renewed interest in this hybrid for biomass production.