I was thinking of putting together a crib for the identification of Valerianella, which common wisdom holds that the British species can only be distinguished by fruit characters. Upon starting my research I discover that some botanists (including the authors of the Flora Iberica treatment of the genus) consider Valerianella carinata and Valerianella locusta (the commonest of the 5 British taxa) to be conspecific, the difference in fruit shape being a case of intraspecific polymorphism. In this treatment the two taxa are reduced to formae under Valerianella locusta (f. carinata and f. locusta).
Valerianella dentata and Valerianella rimosa are similarily united.
This would reduce the number of British species to 3. They’re still difficult to distinguish (keys use fruiting calyx characters), but plants found in ruderal situations in most of the country would be nearly certainly Valerianella locusta sensu lato. I find myself asking the question is whether the 3 broader species can be distinguished in flower by calyx characters, or whether fruits would still be required for identification.
Tangentially, there’s also a movement to return Valerianella locusta to Linnaeus’ original placement as Valeriana locusta. Molecular data has Centranthus, Fedia and Valerianella nested within Valeriana. From what I’ve read so far it seems that Fedia should be sunk in Valerianella. Valerianella could be retained if a small group of species (V. celtica, V. elongata, V. saxatilis (etc.?) were segregated from Valeriana. Centranthus is more deeply nested; either Centranthus ruber becomes Valeriana rubra, or Valeriana gets chopped up further.
I find this interesting, if a little recherche for me (who considers it a ‘win’ if I can correctly get to genus). I had also forgotten (or not known to start with) that Centranthus is a close relative.
Who is the ‘governing’ body in the UK on such matters, please?
To the extent that there is a governing body, it would be the BSBI (Botanical Society of Britain and Ireland), who, if I understand correctly, follow the 4th edition of Stace’s New Flora of the British Isles, with modifications for “critical” taxa not split therein (i.e. brambles, dandelions and hawkweeds, where they may follow Sell & Murrell’s Flora of Great Britain and Ireland), for extreme rarities not covered in the Floras, and for recently discovered species (there’s a steady drip of brambles, dandelions, hawkweeds, and even whitebeams).
But you can see that it’s not a real governing body by the fact that iSpot doesn’t follow the BSBI.
I suffer from the tension between following the BSBI’s classification or following my own taxonomic opinions. (For example, I think the common “Dutch” Crocus in Britain is Crocus neglectus rather than Crocus neapolitanus, and would split Asplenium trichomanes, Dryopteris affinis and Lamiastrum galeobdolon. I find the case for the Valerianella merges moderately convincing.)
There’s also the specific policies of individual vice-county recorders. If you look at BSBI Maps you can see that daffodils are recorded differently according to where in the country you are.
Absorbing… the Flora Helvetica key is based on fruiting characters as are others I came across.
This article attempts to address the problem. This publication may be behind a paywall.
I thought I’d share it in case contributors here are interested.
Ir. Nat J. Volume 26 No 9 2000. Morphological variation in Valerianella (Valerianaceae) in Ireland. J. Parnell, & C. Foley.
J. Parnell constructed the following key using non-fruiting characters, which he wishes readers to field-test and comment on and elements of which may thereafter be incorporated into the next edition of Webb et al. (1996).*
Basal leaves 3 mm wide or less; partial inflorescences usually c. 7.5 mm
wide, sometimes less ………………………………………………………………… 2
Basal leaves 5 mm wide or more; partial inflorescences c. 4.5 mm wide … 4
Flowering stem < 5 cm or plant acaulescent; leaves in basal rosette 3 or
Fewer ………………………………………………………. V. locusta var dunensis.
Flowering stem > 5 cm; leaves in basal rosette 4 or more ……….…………… 3
Usually more than 40 flowering heads per plant; basal rosette leaves usually absent, rarely 1 …………………………………………………… V. rimosa
Usually 35 or fewer flowering heads per plant; basal rosette leaves usually 1 -2 ………………………………………………………………………………V. dentata
Basal rosette obvious …………………………………………………… V locusta
Basal rosette absent or very small ………………………………………. V. carinata
*Footnote. Webb died in a car accident on the way to Reading Herbarium. The next edition of Webb was called Webbs Irish Flora in his honour. Whether this key was field-tested and/or the results incorporated, I do not know.
Note; The formatting I drafted for the key seems ignored above.
