Hieracium maccoshiana T.C.G.Rich,

Rich, Timothy C. G., 2011, Hieracium maccoshiana, a new Scottish hawkweed related to H. dovrense (Section Alpestria, Asteraceae), PhytoKeys 3, pp. 1-8: 2-4

publication ID

http://dx.doi.org/10.3897/phytokeys.3.920

persistent identifier

http://treatment.plazi.org/id/FEB99493-EA5A-8D65-FFA3-5805FA30D44C

treatment provided by

PhytoKeys by Pensoft

scientific name

Hieracium maccoshiana T.C.G.Rich
status

sp. nov.

Hieracium maccoshiana T.C.G.Rich  sp. nov. Figs 1View Figure 1 2 D–NView Figure 2

Latin

Rosula basalia sub anthesi fere absenti. Foliis caulinis 4-8 ellipticis dentibus magnis. Pedunculis pilis multis stellatis pilis eglandulosis simplicibus multis pilisque glandulosis paucis. Bracteis involucralibus 2-2.5 mm latitudinis pilis stellatis paucis pilis eglandulosis simplicibus multis pilisque glandulosis multis. Ligulis apice glabris. Stylis obscuris.

Holotype:

Scotland. Sutherland: by small stream, Allt na Cuile, Rhiconich, 58.4470, -4.9300, 150 m alt., 26 July 2010, M. Jannink (NMW, accession number V.2010.1.213).

Description.

Stem to 50 cm, pale green, slightly purple–tinted below, slender to fairly robust; stellate hairs sparse and mainly above; simple eglandular hairs long, pale, sparse and glabrescent to dense (especially below); glandular hairs very small, occasional; sparsely and minutely puberulous. Basal leaves absent or withering before or up to flowering time or rarely persistent, few. Lamina elliptical or subrotund; apex obtuse–mucronulate; base attenuate; margins remotely denticulate to coarsely dentate; with a few, pale, medium simple eglandular hairs above and below or nearly glabrous above. Petioles winged and broadened at base, with numerous medium to long, pale simple eglandular hairs. Stem leaves and inflorescence bracts (3 –)4– 8, 2-10 × 0.8-3.5 cm, gradually decreasing in size upwards, pale green on upper surface, paler beneath. Lamina of the lower leaves elliptical; apex obtuse–mucronulate to acute; base attenuate; margins denticulate to sharply and irregularly dentate with ascending teeth; petiole winged, semiamplexicaul. Lamina of the median leaves elliptical; apex obtuse–mucronulate to acute; base rounded or abruptly contracted, sessile, semiamplexicaul; margins denticulate to sharply and irregularly dentate with large or small, ascending, mammiform teeth. Lamina of the upper leaves lanceolate; apex acute to acuminate; base cuneate, sessile, semiamplexicaul, margins denticulate to shallowly dentate. All stem leaves with stellate hairs few to sparse on both surfaces; simple eglandular hairs few to numerous below and nearly glabrous above, pale, medium. Inflorescence usually with 2 –9(– 12) capitula, rather compactly cymose. Peduncles 1-5 cm (acladium 0.3-2 cm), suberect, slender; stellate hairs sparse to dense; simple eglandular hairs few to numerous, short to medium, dark–based; glandular hairs few, very short, black. Capitula 20 –30(– 45) mm in diameter, subtruncate at base. Involucral bracts 9-11 × (1.7 –)2.0– 2.5 mm (the outermost from c. 5 mm long), all linear–lanceolate, blackish–green; apex obtuse; stellate hairs sparse, often with a tuft at the apex; simple eglandular hairs many, short to medium, dark–based; glandular hairs many, very short, black. Ligules yellow, glabrous–tipped. Styles discoloured. Achenes 4.0-4.5 mm, blackish–brown. Margins of receptacle pits long–dentate. Chromosome number 2n = 36 (cf. Sell and Murrell 2006, as Hieracium dovrense  ).

Distribution.

Endemic to Sutherland, Scotland, where it is known from four sites in Sutherland: in a gorge and on a burn side near Rhiconich; on a burn side in Coire Dùail, Foinaven; and on rocks at Creag na h-Uidhe ( Fig. 3View Figure 3). The status of plants from Ben Loyal remains to be clarified when it has been refound in the field.

Ecology.

Mountain cliff ledges and rocks, in rocky ravines and on riversides. It mostly occurs out of the reach of large herbivores such as deer or sheep as, like most leafy hawkweeds, is likely to be selectively eaten. The altitudes range from 130-414 m. It flowers from late July to August, and is probably apomictic. Some plants may produce sparse pollen and others none ( Thomas et al. 2011).

Etymology. The epithet honours David J. McCosh for his work in mapping British and Irish Hieracium  taxa over the last 30 years, and for mentoring me. The spelling ‘maccoshiana’ ' follows recommendation 60C.5.a of the International Code of Botanical Nomenclature (Vienna Code McNeil et al. 2006).

Conservation status. Surveys in 2010 revealed about 60 plants in four sites (see supplementary file 1: Hieracium dovrense  survey 2010). It is thus best considered at IUCN (2001) threat status ‘Endangered’ due to the small population size.