Myosotis laxa Lehm., (= M. caespitosa K.F. Schultz), Tufted
Forget-me-not

Account Summary

Growth form and preferred habitats

Among the members of the Myosotis scorpioides agg., the B & I wetland water Forget-me-nots, M. laxa is distinct in being a summer annual or biennial, with the hairs on the plant always adpressed – ie no spreading hairs, especially on the calyx – and its flowers having a short style which does not protrude from the calyx when the corolla drops off or is removed (Welch 1967; Parnell & Curtis 2012). Stems of M. laxa are pale green, leafy, either simple or branched from near the base, grow to a height of between 20 and 40 cm and produce hermaphrodite (bisexual) flowers in a terminal cyme from May to August. The corolla is 4-5 mm in diameter, bright sky-blue with a yellow rim at the throat (Sell & Murrell 2009).

Although often occurring together, M. laxa and its common perennial relative, M. scorpioides (Water Forget-me-not) differ fundamentally in their life strategies and dominant mode of reproduction and spread. M. laxa is entirely dependent on seed production for increase, spread and overwintering survival. Both these species are common and widespread in damp to wet, fertile, open, disturbed marshy ground with a permanently high water-table around or along the margins of a wide variety of usually lowland habitats, including wet hollows in fields. Of the two, M. laxa is the more likely to occur in strongly acidic and hilly or upland sites. In lowland situations, it often occurs in trampled, cattle-poached and manured mud silt, clay or peat, or by brackish ditches (Welch 1967; Sinker et al. 1985).

The wider, more local distribution of M. laxa undoubtedly reflects its greater range of soil tolerances compared with M. scorpioides, the latter being confined to wetter, more muddy, much less acidic to alkaline, lowland terrain, usually with a soil reaction above pH 5.0 (Grime et al. 1988, 2007). M. laxa is tolerant of light grazing and half-shade, but not competition from tall vegetation. As a ruderal annual, it is sometimes a pioneer colonist of bare mud and associates with species such as Alopecurus geniculatus (Marsh Foxtail), Galium palustre (Common Marsh-bedstraw), Glyceria fluitans (Floating Sweet-grass), Ranunculus flammula (Lesser Spearwort), R. sceleratus (Celery-leaved Buttercup) and Veronica beccabunga (Brooklime) (Sinker et al. 1985).

Variation

There are two geographically distinct subspecies within M. laxa. Subsp. laxa is confined to N America, while the B & I and Old World form is subsp. caespitosa (Schultz) Hyl. Ex Nordh. (= M. caespitosa Schultz) (Sell & Murrell 2009).

Fermanagh occurrence

As noted in the account on this website of the ecologically rather similar but definitely perennial patch-forming species M. scorpioides, this annual or biennial species is the more widespread of the three Fermanagh wetland Forget-me-nots, having records in 244 tetrads, representing 46.2% of those in the VC. The comparable figures for M. scorpioides are 198 tetrads, representing 37.5% of Fermanagh's area, and for M. secunda (Creeping Forget-me-not) 107 tetrads and 20.3% of the area. Identification errors have been made in the past, where small-flowered forms of M. scorpioides have been listed as M. laxa, over-recording which needs to be borne in mind when comparisons are drawn.

M. laxa is, however, very comfortably the most widely distributed Myosotis species in Fermanagh, but locally it still has less than half the record frequency of the perennial M. scorpioides. This is probably an artefact produced by the huge degree of over-sampling carried out around Upper Lough Erne by EHS Habitat Survey Teams in 1986-7.

A hybrid

"The species of Myosotis series Palustris, the wetland Forget-me-nots need to be identified with care, and few observers have learnt to recognise this hybrid." (T. O'Mahony, in: Stace et al. 2015). The hybrid between the two wetland Forget-me-not species, M. laxa subsp. caespitosa and M. scorpioides (M. × suzae Domin), has been found scattered amongst the parents in parts of England and Wales and probably it has been overlooked elsewhere on many occasions, including in Fermanagh. The only Irish records are from Co Cork and are unpublished findings by T. O'Mahony (Stace et al. 2015). The hybrid is intermediate between the parent species and has been also been recorded in continental Europe (Sell & Murrell 2009). Patch forming plants that resemble M. scorpioides, but have oddly long racemes that continue to flower well into the autumn, should be examined to see if they belong to this partially fertile intermediate hybrid (New Flora of the BI 1997; BSBI Plant Crib 1998; Stace et al. 2015).

British and Irish occurrence

M. laxa subsp. caespitosa is widely distributed across the whole of B & I, being represented in the New Atlas in a total of 3,175 hectads (167 more than M. scorpioides), but generally it is not as abundant as the latter. Apart from local losses of suitable habitat in SE England, the distribution appears stable, showing little change since 1962 (D. Welch, in: Preston et al. 2002).

European and world occurrence

M. laxa subsp. caespitosa is found in most of Europe and in Asia extends east to N Siberia, the Himalaya and Japan. It is also present in N Africa and has been introduced to New Zealand. The other subspecies, subsp. laxa, occurs in N America. Thus, taken together, the overall species belongs to the circumpolar boreo-temperate element (Hultén & Fries 1986, Map 1560; Sell & Murrell 2009).

Names

The Latin specific epithet 'laxa' means 'open' or 'loose', probably referring to the coiled cymose inflorescence. The Latin subspecific name 'caespitosa' is derived from two words 'caespes' and 'itis' which translate as 'turf sod', meaning the plant is tufted or forms tussocks, which in this annual species is not really the case (Gilbert-Carter 1964).

Threats

None.

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