Nuphar advena (Aiton) W.T.Aiton

Lansdown, Richard & Ruhsam, Markus, 2022, YELLOW WATER LILIES (NUPHAR, NYMPHAEACEAE) IN GREAT BRITAIN: A NEW HYBRID, A REAPPRAISAL OF RECORDS, AND A REVISED STATUS OF N. ADVENA, Edinburgh Journal of Botany 79 (1925), pp. 1-15 : 8

Nuphar advena (Aiton) W.T.Aiton

Most leaves emergent, vertical or at a steep angle, few (if any) lying flat on the water (see Figure 9 ), typically persistent at least until September; petiole rounded or angular in section ( Figure 6 A ). Sepals 6, the 3 (or 4) outer mainly green, the 3–8 inner yellow with a green patch at the base, occasionally tinged reddish to peach coloured ( Figure 7 A ). Filaments 6.3–7.8 mm, pale yellow; anthers 4.2–5.8 mm, deep purple with two lines of whitish yellow pollen ( Figure 8 A ); ratio of anther to filament length, 1.3–1.6. Capsules developed, ovoid to broadly obovate, which contrasts with the urceolate shape in Nuphar lutea .

Material examined. United Kingdom. Berwickshire. Aquatic herb with leaves erect, standing proud of water surface ; outer tepals externally green at base and red or yellow above, red within; inner tepals yellow, suffused reddish within; stigmatic column yellow on top. Lake margin; growing in water, Spottiswoode Loch (Berwickshire, UK) east side, NT61034928 , 19 vii 2021, D. G. Long No. 47192 with R. V. Lansdown , E01004414 ( E) .

Nuphar advena is currently known from a single confirmed site in Britain in the lake on the Spottiswoode Estate, Berwickshire, where it was first recorded in 1964 ( Long, 1998, 2020). It forms two large stands along the margin of one side of the lake.

Figures

Figure 6. A, Petiole shape of Nuphar advena from NA1 population, Spottiswoode Loch. B, Petiole shape of Nuphar × porphyranthera from NH8 population, Oulten Park (left); NH6 population, Shropham Ponds (centre); and NH1 population, West Hoathly (right). C, Petiole shape of Nuphar lutea (no population code), Elterwater. Scale bars are approximate (no measurements of the photographed features were taken). Photographs: R. V. Lansdown.

Figure 7. Sepals of: A, Nuphar advena from NA1 population, Spottiswoode Loch; B, Nuphar × porphyranthera from NH8 population, Oulten Park (left), and NH2 population, Godstone (right); C, N. lutea (no population code), Norbotten, Sweden. Scale bars are approximate (no measurements of the photographed features were taken). Photographs: R. V. Lansdown.

Figure 8. Flowers and stamens of: A, Nuphar advena from NA1 population, Spottiswoode Loch; B, Nuphar × porphyranthera from NH8 population, Oulten Park (left), and NH1 population, West Hoathly (right); C, N. lutea (no population code), Elterwater (left) and Pop1 population, Ashtead (right). Scale bars are approximate (no measurements of the photographed features were taken). Photographs: R. V. Lansdown.

Figure 9. Habit of Nuphar advena, showing leaves in July 2021, from NA1 population, Spottiswoode Loch. Photograph: R. V. Lansdown.