Last and Least - Water-lily, that is!

Image: D. Wrench

Great to hear from BSBI member Mags Cousins about a recent trip to find Least Water-Lily Nuphar pumila at Cole Mere SSSI. 

Over to Mags:

"This lovely little lily (on right) is on the England Red List as Critically Endangered. Cole Mere, in Shropshire, is the only remaining site in England".

[LM: You can download the England Red List free of charge from this page.] 

"The next nearest populations are in Scotland, which raises the question, why is there nothing in between, could it simply be a doomed glacial relic? 

Image: D. Wrench

"Apart from its isolation, another significant risk is that it can hybridise with the Yellow Water-lily Nuphar lutea. Both lilies can be found at Cole Mere: are they hybridising already? 

"The species can be distinguished by the shape of the stigmatic disks which is wavy edged or lobed in N. pumila (on left) and smooth edged in N. lutea (below right). 

"This and other features such as leaf morphology can be intermediate in hybrids.

Image: D. Wrench

"Cole Mere is not exactly a pristine location for this rarity as it is a lowland eutrophic mere which suffers from serious algal blooms in most years. N. pumila used to occur in three parts of the mere. 

"There are now only two colonies remaining but these are thought to have expanded recently in response to tree felling on the shoreline that reduced the degree of shading. 

"Could re-establishment occur in other parts of the mere naturally through seed or rhizome fragments? Rhizomes are regularly dislodged and are washed to the shore but did not seem to be rooting again and it was not known if the plants were actually producing viable seed. The image below left shows the uprooted rhizomes, probably uprooted by Mute Swans feeding on the submerged "lettuce leaves!

Image: S. Miles

"With so many questions it was time to get some experts together to find some answers and come up with a conservation plan.

"Natural England, Royal Botanic Gardens (RBG) Kew, Richard Lansdown (Chair IUCN SSC Freshwater Plant Specialist Group), Shropshire Council (the site owners) and the Shropshire Botanical Society set about a review of the status and ecology; the seed and rhizome viability and DNA analysis of the Least Water-lily at Cole Mere.  

Image: R. Lansdown

"We were ably helped by the Colemere Sailing Club who provided transport in the way they know best and the Inner Space Dive Club (on right) who just love any excuse to get underwater, even if the botanical remit was a bit different to their usual excursions: “Please can you count the number of petioles extending from the rhizomes?”

"Great fun was had by all and some really useful findings emerged which will be reported and published in full in due course".

[LM: Mags proposes submitting the manuscript to New Journal of Botany - hurrah!]

"Even better, after lots of intensive care, some brand new seedlings emerged from seed which are being nurtured by the team at Kew and will form the basis for a collection for conservation, public display and education at Kew Gardens". 

Many thanks to Mags for telling us about the Least Water-Lily!