Carex orothanatica Lois, Acedo, Reznicek & Jim.Mejías, 2023

Lois, Raúl, Acedo, Carmen, Reznicek, Anton A. & Jiménez-Mejías, Pedro, 2023, Three newly described species of Carex sect. Fecundae (Cyperaceae) from Central America and typification of two related names, Phytotaxa 579 (2), pp. 71-86 : 73-75

Carex orothanatica Lois, Acedo, Reznicek & Jim.Mejías , sp. nov. ( Figs. 2–4 )

Diagnosis:— The Costa Rican Carex orothanatica is similar to the Guatemalan endemic C. tojquianensis Standley & Steyermark (1953: 64) . Both taxa clearly differ in the morphology of the utricle beak, bifid in C. orothanatica vs. truncate in C. tojquianensis , and by the color of its glumes, purplish-black in C. orothanatica vs. dark brown in C. tojquianensis . This new species is also similar to the much larger Carex cortesii Liebmann (1850: 268) , endemic from Mexico. Both species clearly differ by leaf dimension, 30–40 cm × 4–5 mm in C. orothanatica vs often longer than 100 cm long and 7–8 mm wide in C. cortesii , the number of spikes of the inflorescence, lower than 10 in C. orothanatica vs higher than 20 in C. cortesii , wider and longer utricles in C. orothanatica , 3.3–3.5 × 1.8–2.0 mm than in C. cortesii , 2.2–2.5 × 1.1–1.3 mm.

Type:— COSTA RICA: Province of Cartago: Cordillera de Talamanca : Cerro de la Muerte, Pan-American Highway, 5 km above Villa Mills (about 8 km above Nivel) 9°34’N 83°45’W, crevices in rock ledges and on Paramo, 3400–3500 m, 25 July 1949, R. W. Holm & H. H. Iltis 563 (Holotype: A! ( Figs. 2–4 ); isotype: P!) .

Cespitose, rhizomes densely covered with short yellowish to stramineous hairs. Stems 25–40 cm tall, ± 0.15 mm wide at the middle, smooth, trigonous, sides concave below the inflorescence, reddish-brown at the base. Leaves with welldeveloped blades, largest ones 30–40 cm × 4–5 mm, usually shorter than the stems, linear, subcoriaceous, reddishbrown at the base, W-folded, margin slightly revolute; ligule 0.3–0.4 mm long, acute, orangey-brownish; sheaths orangey-brownish. Inflorescence racemose, 5.0–7.0 cm long, with 7–9 androgynous spikes, spreading or dropping; lowermost bract 5.5–7.5 cm × 2–3 mm, slightly longer than the inflorescence, subcoriaceous, W-folded, sheathless or with a short sheath <3 mm. Spikes 2–3 cm × 5–6 mm, linear to oblong, densely flowered, the distal 1/4 staminate, unbranched, with about 120– 150 female flowers, peduncles smooth, mostly equal or longer than the spikes. Female glumes 3.8–4.0 × 1.6–1.7 mm, ovate to suborbicular, purplish-black with a light green middle longitudinal strip, excurrent into a 0.4–0.5 mm awn, hyaline margins extremely narrow or absent, when present it is along the entire glume length. Stigmas 3, brownish. Utricles 3.3–3.5 × 1.8–2.0 mm, suborbicular, glabrous, brownish-red, smooth, nerveless, contracted at the apex into a 0.3–0.4 mm long beak, smooth, bifid, with the teeth slightly divergent, the sinus between teeth as deep as the whole beak length. Achenes 1.6–1.8 × 0.9–1.1 mm, ovate to elliptic, trigonous, cuneate to round at the base; style strongly lignified, leaving a long cylindrical, 0.2 mm long remnant at the apex of the achene.

Habitat and distribution: —Known only from two collections and one recent iNaturalist observation that confirms the presence of the species (https://www.inaturalist.org/observations/111517173) at Cerro de la Muerte, on the western slopes of Cordillera de Talamanca, growing at an altitude of 3400–3500 m in páramo vegetation.

Phenology:— Flowers and fruits were collected at the end of July.

Etymology: —The epithet “ orothanatica ” is formed by the ancient Greek “ oros ”, mountain, and “ thanatica ”, in reference to “ Thanatos ”, the Death. It refers to the toponym of “Cerro de la Muerte”, which means Mountain of Death, where the type material was collected.

Paratype:— COSTA RICA: Province of San José: Direct line from Hotel La Georgina to Cerro Frío of the Cerro Buenavista complex (Cerro de la Muerte), area with television and radio towers, 9°33’- 34’ N 83 °43’- 46’W, rocky, grassy slope, 3100–3400 m, 20 September 1983, G. Davidse 25041 (MICH!) .

Figures

FIGURE 2. Holotype of Carex orothanatica Lois, Acedo, Reznicek & Jim.Mejías preserved at the Herbarium of the Arnold Arboretum (A) Collection Vascular Plants © Copyright 2013 The President and Fellows of Harvard College.

FIGURE 3. Comparison of diagnostic traits of utricules and glumes of Carex orothanatica Lois, Acedo, Reznicek & Jim.Mejías and relatives. A–B. C. orothanatica (Costa Rica, Holm & Iltis 563, A, holotype). A, utricle; B, female glume C–D. C. cortesii (Mexico, Webster et al. 11557, US-2600628) C, utricle; D, female glume E–F. C. tojquianensis (Guatemala, Rue et al. 648, WIS). E, utricle; F, female glume. Scale bar 1 mm (A–F).

FIGURE 4. Carex orothanatica Lois, Acedo, Reznicek & Jim.Mejías. Detail of the inflorescence (Costa Rica, Holm & Iltis 563, A, holotype). Scale bar 1 cm.