Basionym: — Chamaemelum heterolepis Freyn & Sintenis in Freyn (1895: 349).

Syntypes: — TURKEY. A7 Gümüşhane: in campis as Teke, 4 July 1894, Sintenis 6088b (syntypes B!, G!, Fig. 1); A7 Gümüşhane: probe Ketschi-Kalessi, 5 July 1894, Sintenis 6088 (G, not seen).

Biennial herb, 20–30 cm. Stems many from base, corymbosely branched above. Leaves two-three pinnatisect, laciniae lanceolate - filiform, thickly white-mucronate at tips. Bottom leaves 16–27 mm long, 4–8 mm wide, petioled. Cauline leaves 11–22 mm long, 7–12 mm wide, sessile, with axis widened at base beset with short linear segments. Capitula heterogamous, numerous, radiate, ±densely corymbose, peduncles 20–65 mm long, pubescent, especially dense below the head; involucre 6–10 × 2.5–3.5 mm, ovoid or hemispherical with ca. 25–35 bracts arranged in three to four rows, imbricate; outer bracts 2.5–3.5 × 0.8–0.95 mm, ±pubescent, triangular-acute, ±obtuse or subobtuse, margins whitish membranous; inner bracts 3–4 × 1–1.6 mm, glabrous, oblong-obtuse or subobtuse, margins whitish membranous. Receptacle ovoid or hemispherical ±solid, epaleate. Ray flowers female, 15–20 per capitulum, limbs white, broadly eliptic, shallowly three-lobed at apex, 3.5–6.5 × 1.2–2.5 mm. Disc flowers numerous, hermaphrodite, yellow with five deltoid lobes 0.2–0.4 mm, tube 1.7–1.9 mm, cylindric, widening at base and enveloping top of the achene, corolla lobes glandular at tips; anthers 5, coherent along most of their length and forming a tube around style, appendage conical, blunt at base; style of ray flowers longer than tube bifid; style of disc flowers shorter than flowers, two-parted. Achenes obpyramidal, ±incurved, 1.2–1.5 × 0.3–0.5 mm, blackish or dark brown at maturity, non-mucilaginous, dorsal side tuberculate-rugulose, ventral side three-ribbed, ribs very thin, acute, white, fissures tuberculate-rugulose; corona very small, marginiform, white, crenulate, ca. 1/10–1/8 as long as achene.

Phenology: —Flowering and fruiting June – July.

Habitat: —Meadows and roadsides.

Distribution: — Turkey. It is only known from the type locality in north-east Anatolia.

Conservation status: —CR: B1ab (i,ii,iii)+2ab (i,ii,iii) (previously assessed as DD, according to Ekim et al. 2000; IUCN 2014a). In the type locality, the population of the species seems to be small and scattered. Therefore, it should be regarded as Critically Endangered (IUCN 2014b) because of its local distribution and small population size.

Chromosome number: —2n=4x=36 (Inceer & Hayırlıoglu-Ayaz 2010).

Notes: —This species is only known from the syntypes and our specimens collected from Gümüşhane. Tripleurospermum heterolepis is sympatric with T. callosum, endemic to Turkey, T. repens (Freyn & Sintenis in Freyn 1895: 349) Bornmüller (1944: 337) endemic to Turkey, and T. sevanense. Table 1 details some of the morphological characters used to distinguish T. heterolepis from these species. As suggested already by Enayet Hossain (1975), T. heterolepis closely resembles T. callosum but differs in having the biennial habit and an almost densely corymbose synfloresence. Tripleurospermum heterolepis also resembles T. repens and T. sevanense but differs in having the biennial habit and short coronate achenes. Below is an identification key for these species.

1. Plants biennial............................................................................................................................................................... T. heterolepis

– Plants rhizomatous perennial.............................................................................................................................................................2

2. Ribs of achene conspicuously thickened, obtuse or subobtuse............................................................................................. T. repens

– Ribs of achene very thin, acute..........................................................................................................................................................3

3. Flowering stem corymbosely branched above; synflorescence corymbose..................................................................... T. sevanense

– Flowering stem divided from base or at the middle; synflorescence laxly corymbose................................................. … T. callosum

Additional specimens examined: — TURKEY. Tripleurospermum heterolepis: A7 Gümüşhane: Tekke, Keçikaya Village, 1618 m, 4 July 2007, Inceer 382b (KTUB); A7 Gümüşhane: Tekke, Keçikaya Village, 1579 m, 13 June 2009, Inceer 734 (KTUB). Tripleurospermum callosum: A8 Gümüşhane (Bayburt): Kop Dağı pass, damp alpine pastures, meadows, 2200 m, 14 July 2000, Inceer 69 (KTUB); A7 Gümüşhane: Tekke, Keçikaya Village, 1400 – 1539 m, 4 July 2007, Inceer 379 – 381 (KTUB); A7 Gümüşhane: Keçikaya Village, 1732 m, 13 June 2009, Inceer 736 (KTUB). Tripleurospermum repens: A7 Gümüşhane: Darsosgagh in agris otiotis, 6 june 1894, Sintenis 5766 (B, G, E, type specimens); A8 Gümüşhane (Bayburt): Gezge Village, 1724 m, 8 July 2007, Inceer 383 (KTUB); A7 Gümüşhane: Keçikaya Village, 1580 m, 6 June 2009, Inceer 725 (KTUB). Tripleurospermum sevanense: A7 Gümüşhane: Köse Dağı, 1800 m, 7 June 2001, Inceer 105 (KTUB); A7 Gümüşhane: Köse Dağı, 1800 m, 13 June 2009, Inceer 731 (KTUB).