Anthemis rigida subsp. runemarkii Biel & Kit Tan (2020: 190)

Goula, Katerina & Constantinidis, Theophanis, 2021, Taxonomic diversity and karyology of Anthemis rigida (Anthemideae, Asteraceae) in the Aegean, Greece, Phytotaxa 484 (1), pp. 129-143 : 137-140

Anthemis rigida subsp. runemarkii Biel & Kit Tan (2020: 190) ( Fig. 5 : e,f)

Type:― GREECE. Kiklades : island of Milos, NW of Ag. Mamas, rocky phrygana slopes above coast, 10 m, 36°41’N, 24°25’E, 25 February 2020, Biel 2020.48 (holotype C; see Biel & Tan, 2020) .

Small annual with prostrate to ascending, simple or sparingly branched stems, 1−20 cm long. Stems and leaves tinged with purple, densely tomentose with medifixed hairs when young, laxly tomentose to glabrescent later. Lower leaves long-petiolate, 1-pinnatisect with segments pinnatifid to pinnatisect, glandular-punctate; ultimate lobes at least 2 times longer than wide, oblong-obovate to oblong-ovate, acute to shortly mucronate; upper leaves similar but smaller. Peduncles thickened, becoming rigid and usually recurved in fruit. Capitula solitary, radiate. Involucre 5−8 × 5−7 mm, almost cylindrical, bracts usually in 2−3 rows, imbricate, unequal in length, tomentose when young, thick, rigid, and glabrescent in fruit, often tinged with purple. Outer involucral bracts narrowly lanceolate to ovate-lanceolate, 2.5−4 × ca. 1 mm, usually not more than 1/2−2/3 as long as inner bracts, with scarious margins up to 0.4 mm. Inner bracts obovate, 5−6 × ca. 1.5 mm, with broad scarious margins up to 0.5 mm. Ligulate florets with ligules oblong-ovate, toothed at apex, 5−8 × 1.7−2.5 mm, dark to pale pink, white tinged pink or white, glandular punctate, sterile; disc florets ca. 3 mm, yellow, glandular punctate. Anthers, style, and pollen yellow. Receptacular scales hyaline, obovate to oblanceolate, mucronate and becoming lacerate at apex. Achenes obconical, faintly ribbed; outer achenes ca. 2 × 1 mm, with a corona 0.5−0.9 mm long; inner achenes longer and thinner, 2−2.8 × 0.6−0.8 mm, with a corona 0.4−0.8 mm long.

Distribution and habitat:―This subspecies is endemic to Milos island group and has been located so far on the following islands and islets: Milos, Kimolos, Prasonisi, Poliegos, at elevations from sea level to ca. 87 meters. It has been found in a number of different habitats such as sandy shores, rocky and gravelly places next to the sea, phrygana formations, maquis and periodically flooded areas, all on acid volcanic substrates.

Notes:―Although the pink-coloured ligules is a remarkable trait observed in this subspecies, it is not characteristic of all the known populations. Ligules in various shades of pink, from deep- to pale-pink, or white tinged pink, or totally white have been recorded, even among individuals from the same locality. The morphological features that separate Anthemis rigida subsp. runemarkii from the rest of the ligulate subspecies are mainly the narrow leaf lobes, the longer and wider involucre and the broad scarious margin of the outer involucral bracts ( Fig. 5 , Table 5). The “adpressedpubescent” achenes that Biel & Kit Tan (2020) mention in their description raises serious questions about achene morphology for the entire genus: the only report of hairy achenes among the Anthemis species of Europe ( Fernandes 1976), Turkey ( Grierson & Yavin 1975), N Africa ( Oberprieler 1998), Middle East ( Eig 1938; Iranshahr 1986, Ghafoor & Ali 2002) and Saudi Arabia ( Ghafoor 2010) concerns “a single poor specimen with somewhat hairy young achenes” that Eig (1938) mentions from Ramadi, Iraq. A thorough examination of achenes in all the specimens collected on Milos do not indicate the presence of any pubescence.

As previously mentioned, Anthemis rigida subsp. runemarkii co-exist with A. rigida subsp. rigida on the island of Milos. In the areas where the two taxa meet, subpopulations with intermediate features have been recorded. Similar cases are reported by Greuter & Rechinger (1967) for populations on Kithira and Antikithira islands.

Figures

FIGURE 5. Photographs of Anthemis rigida in the field (a, c, e, g) and in cultivation (b, d, f, h): A. rigida subsp. rigida from Kriti (a & b); A. rigida subsp. liguliflora from Kithira (c & d); A. rigida subsp. runemarkii from Milos (e & f); A. rigida subsp. antri-neptuni from Karpathos (g & h) (all photos taken by the first author except c, by Stavroula Fatsea).