Leontodon hochstetteri M. Moura & L. Silva, 2015

Moura, Mónica, Silva, Luís, Dias, Elisabete F., Schaefer, Hanno & Carine, Mark, 2015, A revision of the genus Leontodon (Asteraceae) in the Azores based on morphological and molecular evidence, Phytotaxa 210 (1), pp. 24-46 : 35-36

Leontodon hochstetteri M. Moura & L. Silva nom. nov.

≡ Microderis umbellata Hochstetter ex Seubert (1844: 33) .

Holotype:— AZORES. “in dumetis montis ‘ Pic de Pico’ supra Villa Magdalena”: 1838, C. Hochstetter s.n. ( TUB!, isotype: P!).

− Picris hochstetteri C. H. Schultz Bipontinus nom. non rite public.

Acaulous rosettiform rhizomatous perennial herb; white latex present. Rootstock usually stout, sometimes a long napiform root. Leaves few to several (1–11), petiolate; petiole (2.0–) 7.6 (–20.3) cm long × (0.4-) 1.4 (-4.0) cm wide, grooved, often narrowly winged; petiole trichomes often simple; leaf (7.3-) 15.2 (-34.8) cm long × (2.5-) 7.8 (-19.2) cm wide; elliptic to ovate or obovate, attenuate at base onto apex of petiole; usually sparsely pubescent above and densely pubescent beneath, hairs about 1 mm long or longer and attenuate, apices simple and straight, curved or appearing almost uncinate or often bifid; venation pinnate, usually paler than lamina, midrib prominent beneath, with many hairs, grooved above; margins flat to coarsely undulate, serrate, coarsely serrate or sometimes deeply lobed at base, lobes simple or sometimes bifid; lamina apices acute, obtuse or rounded. One or two flowering stipes up to (17-) 34 (-60) cm tall; ramification generally initially dichotomous at the middle, with 2–5 proximal ramifications and with multiple distal ramifications; dense umbellate panicle, barely aphyllous, stipe striate, moderately hispid pubescent at the base but almost glabrous at peduncles and pedicels, usually with one leaf-like bract beneath main branches and scale-like bracteoles beneath upper branches; stipe trichomes simple to bifid; pedicels (0.3-) 1.2 (-3.6) cm long, usually thickening below involucre, bracteolate, bracteoles scale like, (1-) 4 (-12) mm long; the pedicel bracteoles sometimes also found at the base of the capitulum forming an incomplete, unequal calyculus around 2–3 mm long. Capitula ligulate, (0.4-) 1.1 (-2.5) cm in diameter, (12-) 58 (-134) per synflorescence; involucre cylindrical in bud and scarcely widening in flower at apex, base becoming slightly inflated postanthesis and in fruit; phyllaries biseriate, external bracts (1.0-) 2.8 (-5.4), internal bracts (3.1-) 7.2 (11.0) mm long x (0.3-) 0.8 (2.2) mm wide, margins glabrous below and sparsely ciliate towards apex, tissue papillate and usually blackish; receptacle flat, paleaceous, paleae c. 3.9–9.8 mm long × 0.1–0.7 mm wide, linear, usually dark, apices attenuate/long-acute, sparsely to moderately ciliate, cilia long uniseriate and eglandular. Florets (21-) 43 (-56) ligulate, hermaphrodite, fertile, corollas yellow to orange but becoming brown postanthesis, eventually deciduous; corolla tube (0.8-) 2.6 (-5.1) mm long, glabrous, pale yellow, ligule (5.6-) 9.0 (17.2) mm long × (0.4-) 1.4 (-5.1) mm wide, glabrous inside, sparsely pubescent outside just above sinus with eglandular hairs, ligule apex with five distinct teeth, teeth apices thickened, glabrous; anther cylinder yellow (2.3-) 3.6 (-5.2) mm long, apical anther appendages obtuse to broadly rounded, slightly longer than wide, basal anther appendages sagittate; styles (2.5-) 5.0 (-6.7) mm long, style arms (0.8-) 1.2 (-1.6) mm long, ascending or divergent, very short pubescent outside throughout. Achenes (0.4-) 1.2 (-3.2) mm long × (0.1-) 0.3 (-0.6) mm wide, narrowly fusiform, narrowing slightly upwards to a distinct apical callus, body striate, lightly rugose across striae; pappus setae (3.1-) 5.3 (-7.3) mm long, setae at first coarsely scabrid, and about as long as corolla tube, maturing to plumose or subplumose, with setae rachis coarsely barbellate. Molecularly differs from all other Azorean Leontodon in 5 positions of the ITS region, in the motifs CCGC T GGCG ( C replaced by T), GTCA A GCTG ( G replaced by A), CTGT T GCGG ( C replaced by T), CCCT T CAGC ( C replaced by T) and GTTT G AGGA ( T / C replaced by G); in one position of the matK region, in the motif AAGA G AGCC ( A replaced by G); and in a deletion in the trnV region, in the motif TTTT- AGTT ( T deletion).

Notes: — Seubert & Hochstetter (1843) used the name Microderis umbellata to refer to this taxon, the type of which, collected by Karl Hochstetter, is at TUB. The name cannot be used due to the existence of L. umbellatum Schrank (1789: 334) . Another Karl Hochstetter specimen is at P and was labelled “ Picris hochstetteri C. H. Schultz Bip. 29/360” by C. H. Schultz-Bipontinus. There is no evidence of this name ever being validly published and the replacement name L. hochstetteri is proposed here.Although the types of Microderis umbellata are labelled as collected at Pico, we believe this was a labelling error because the species is mentioned twice in Seubert & Hochstetter (1843) as specific to Flores Island. The holotype at TUB matches the drawing and protologue in Seubert (1844).

Distribution: — Leontodon hochstetteri is known only from the islands of Flores and Corvo.

Habitat: —Steep slopes, ravines, craters, rocks, coastal cliffs and waterfalls. From almost sea level up to above 900 m. More frequent above 300 m. In the margin and in the openings of native forest ( Laurus azorica , Juniperus brevifolia ) and woodland ( Juniperus brevifolia ). In Corvo it is rare due to strong grazing pressure by feral goats and sheep, but survives inside the island’s central crater “Caldeirão” in rock outcrops covered by low stature native vegetation and in the steep coastal cliffs of the western and northern part of the island.

Phenology: —All three Azorean endemic Leontodon species have similar flowering times, starting from the end of June until November; flowering specimens have been observed during the month of December, in years with mild winter conditions. Overlapping phenological states are common during the summer months with a mix of vegetative, flowering and fruiting plants in the same population. Within the populations screened for the present study and that of Dias et al. (2014), we observed that neighbouring plants with similar size do not flower synchronously and only ca. 60% of a population’s individuals develop flowers yearly.

Conservation Status:—The number of endemic Leontodon individuals estimated by Schaefer (2005) for Flores was 4,000 –5,000. However, L. hochstetteri is rare in Corvo, where <1,000 individuals are estimated to survive in inaccessible places. On Flores it is strongly grazed by rabbits, wherever they can reach it; on Corvo rabbits are so far absent but the presence of grazing cattle inside the Caldeirão crater and rim (considered as a Biosphere Reserve in 2007 by UNESCO) as well as feral goats and sheep, which can enter the island cliffs, constitutes a severe threat to the survival of L. hochstetteri as well as to several other Azorean endangered endemic plants, and should thus be regulated. According to the IUCN classification, and based on the estimated number of plants, L. hochstetteri would be considered as Vulnerable (V) B1ab(i,ii,iii)+2ab(i,ii,iii); C2a(i).