Carex roalsoniana Jim.

Jiménez-Mejías, Pedro & Escudero, Marcial, 2016, Notes on South American Carex section Schiedeanae and description of the new species Carex roalsoniana, Phytotaxa 260 (2), pp. 185-192 : 186-187

1. Carex roalsoniana Jim. -Mejías & M.Escudero, sp. nov. ( Figs. 1–2)

This new species is similar to Carex subandrogyna G.A.Wheeler & Guagl. , native from northern Argentina and Bolivia, and to Carex lepida Boott from Ecuador. From C. subandrogyna the new species clearly differs in utricle morphology (3.6–4.1 mm long, with a beak 0.5–1.2 mm in C. roalsoniana vs. 2.4–2.9 mm long, with a beak up to 0.3 mm long or beakless in C. subandrogyna ) and leaves (up to 3–4 mm wide, stiff, in C. roalsoniana vs. up to 5.6–7.5 mm wide, very soft in C. subandrogyna ). From C. lepida the new species differs by its habit densely caespitose and by having trigonous achenes with three stigmas ( C. lepida has long rhizomes and biconvex achenes with two stigmas). The glabrous nerveless utricles of the three South American species readily distinguish them from the North American species of the section that have scabrid to hispidulous, conspicuously nerved utricles.

Type: — ECUADOR. Azuay: the eastern Cordillera, 1–8 km north of the village of Sevilla de Oro , 8,000–9,000 ft., in cliffside seepage, plants in clumps, 12 Aug 1945, W. H. Camp 4662 (holotype NY! Figs. 1–2; isotypes A! Fig. 2 , K, MICH) .

Perennial; caespitose. Stems 10–52 cm long, 0.8–1.2 mm width in its middle length, shorter than or as long as the leaves, trigonous, with narrowly winged margins, faintly scabrid in most its length, with pickles in both antrorse and retrorse directions; basal sheaths up to 2–2.5 cm high, soft, ± entire, dark brown. Leaves flat or slightly M shaped in cross section, hypostomatic, the uppermost of the flowering stems with a blade 23–54 cm long, the widest with a blade 3–4 mm width; ligule 4–8 mm, longer than wide, acute, hyaline; lowermost leaves reduced, with a short blade and the side opposite to the blade brownish. Inflorescence 1.9–3.6 cm long, with 2–3 androgynous spikes, sometimes one of them reduced, the lowest one ± covered at the base by the lowermost bract; lowermost bract 6–13 cm × 1.7–3.5 mm, much longer than the inflorescence, sheathless; second lowermost bract 2.5–5.4 cm × 0.8–2.2 mm, longer than its spike. Spikes androgynous, densely flowered, with up to 40–50 utricles, being the female part much more developed than the male one; uppermost spike 20–22.5 × 4.5–5 mm, generally larger than the lowermost one, with a male part 1.5–4 mm long; lowermost spike 11.7–20 × 3–4.5 mm, with a male part 1.7–3.5 mm long; cladoprophylls present at the base of each spike, ± 2.2 mm long, utriculiform, hyaline to reddish, with a funnel-shaped beak with ciliate borders, containing a female flower although frequently aborting it, if developing then the achene body protrudes from the cladoprophyll beak. Male glumes 2 × 0.6–0.8 mm, entirely hyaline or with the central nerve green, acute, scabrid above, crowded at the top of the spike. Anthers 0.7–0.8 mm long, filaments 1–1.6 mm long, reddish. Female glumes deciduous, dropping before utricles, with a body 2.5–4 × 0.6–1.4 mm, hyaline, narrowly obovate to oblong, with a central band greenish with 1–3 nerves, acute, mucronate, the ones from the middle part of the spike with the mucro 0.5–1.1 long, sparsely scabrid. Utricle 3.6–4.1 × 1.4–1.6 mm, elliptical, soft, membranaceous, hyaline to straw-colored, nerveless except for the two lateral nerves, attenuated into a 0.5–1.2 mm smooth beak. Stigmas 3, very short, conspicuously convolute backward, reddish-brown and densely papillose; style base bulbous, deciduous, leaving a flattish lignified remnant at the top of the achene. Achene 2.1–2.9 × 1.2 mm, trigonous; rachilla vestigial (~ 0.1 mm) or absent.

Habitat and distribution: —Known only from two populations, one in Ecuador and another one in Peru, placed at a straight-line distance of 233 km one from another. Both populations are in western facing slopes of the Andes foothills, at an altitude of 2400–2800 m. The indications provided in the herbarium labels associate the habitat of this new species to moist environments (forest, seepages on cliffs). Such ecological preferences are more similar to the requirements of C. subandrogyna , which grows in shady subtropical montane forest (“yungas”; Wheeler & Guaglianone, 2003, 2006), than to the North American species, which are found in dry, subdesertic habitats (Reznicek, 2003; Gómez-Sánchez et al., 2012).

Phenology: —Flowers and fruits were collected from May to August.

Etymology: —Dedicated to Eric H. Roalson, North American botanist and professor of the Washington State University, expert in systematics, taxonomy and evolution of Cyperaceae , who continuously promoted and encouraged to develop the knowledge in Carex .

Additional collections (paratypes): — PERU. Ayabaca: Piura, ruinas de Aypate, 4° 42.094’ S – 79° 34.252’ W, 2700–2800 m, bosque secundario intervenido, 22 May 1996, V. Quipuscoa et al. 569 (F!, MO).

Observations: —The name “ Carex erythrogyne Nees ” found in the vouchers from the collections from Ecuador seems just to be a labeling error. The name is not listed in the International Plant Names Index (www.ipni.org), neither in the World Checklist of Cyperaceae ( Govaerts et al., 2016) . We also unsuccessfully searched for this name in Steudel’s Synopsis Plantarum Glumacearum (1853–1855) and Boott’s Illustrations of genus Carex (1858–1867), where some name authorities are assigned to Nees. In addition, we requested for the existence of possible type material under this name in herbaria that could harbor Nees’ collections (B, BR, CGE, GE, GZU, HBG, K, M, MSB, NHV, STR, UPS; Stafleu & Cowan (1976–1997), abbreviations according Thiers (2015)) and received a negative response from all of them.

Figures

FIGURE 2. Detailed pictures of the holotype (A; NY herbarium) and isotype (B–G; A herbarium) of Carex roalsoniana Jim.-Mejías & M. Escudero. A. Inflorescences; notice in the upper inflorescence that the lowermost spike is covered by the bract; the arrow depicts the male segment at the top of an androgynous spike. B. Spike axis after most utricles are dropping; the arrow depicts the utriculiform cladoprophyll from which the spike axis protrudes; notice that the male segment at the top of the spike remains after the utricles and female glumes has dropped. C. Female glumes. D–E. Ripe utricles, abaxial side; notice in D the short style with strongly convoluted backward stigmas. F–G. Ripe achenes. Scale bar = 1 mm.