Anthemis rigida, Goula, Katerina & Constantinidis, Theophanis, 2021

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

Anthemis rigida subsp. antri-neptuni Goula & Constantinidis subsp. nov. ( Fig. 5 : c, d)

Type:― GREECE. Dodekanisa : Karpathos Ιsland, 1.7 km SW of Pigadia, phrygana formations, sandstone, 48 m, 35°30’N 27°11’E, 30 April 2019, Goula, Bazos & Constantinidis 2772 (holotype, ATHU!) .

Small annual with prostrate to ascending, simple or rarely sparingly branched stems 1−6 cm long, green in flower, becoming brown or brownish-purple in fruit. Stems and leaves 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 usually about as long as wide, widely ovate-lanceolate to triangular, mucronate; upper leaves similar but smaller. Peduncles thickened, becoming rigid and often recurved at fruit. Capitula solitary, radiate. Involucre 2−3 × 4−5 mm, obconical, with bracts usually in 2−3 rows, imbricate, subequal, 1.8−2.8 mm long, densely tomentose when young, thick, rigid and less tomentose in fruit. Outer involucral bracts ovate-lanceolate, ca. 1 mm wide, usually only slightly shorter than inner bracts, with narrow scarious margins up to 0.2(−0.3) mm. Inner involucral bracts obovate, 1−1.5 mm wide, with scarious margins 0.3−0.5 mm. Ligulate florets with ligules elliptic to oblong-ovate, toothed at apex, 4−5.5 × 1.3−2.3 mm, white, glandular punctate, sterile; disc florets 2−2.5 mm, white or tinged pink, glandular punctate. Anthers before dehiscence and style brownish-red, pollen yellow. Receptacular scales hyaline, ovate-lanceolate, aristate and becoming lacerate at apex. Achenes 1.3−1.8 mm long, ribbed, brownish-purple, with the apex usually obliquely cut or having a small corona up to 0.2 mm; outer achenes widely obconical to almost cylindrical, 0.8−1 mm wide; inner achenes obconical, 0.6−0.8 mm wide, with a small corona 0.1−0.3 mm.

Distribution and habitat:―This subspecies is endemic to Karpathos, where it is found on the south-eastern part of the island. So far, it has been located from sea level to ca. 120 m, in phrygana communities and seasonally wet places, on sandstone or clayey flysch.

Etymology:―The subspecific name (“antrum”, cave and “Neptunus”, the Roman god equivalent to Greek Poseidon “ΠΟΣΕΙΔών”) derives from the locus classicus, which is very close to the cave of Poseidon, god of the waters and the sea, according to the Greek mythology.

Notes:― Anthemis rigida subsp. antri-neptuni is a distinctive taxon, due to the brownish-red anthers and style and the broad ovate-lanceolate to triangular ultimate leaf lobes ( Fig. 5 ). The carpological characters are also unique, as both outer and inner achenes lack or have very small coronas up to 0.3 mm. Anthemis rigida subsp. rigida has also been recorded on Karpathos. No intermediates with A. rigida subsp. antri-neptuni have been observed.

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).