Aristida tovariana Harol Gutiérrez, 2018

Gutiérrez, Harol, Castañeda, Roxana & Montesinos-Tubée, Daniel B., 2018, Aristida tovariana (Poaceae, Aristidoideae), a new species from the Andes of Southern Peru, Phytotaxa 362 (1), pp. 105-111 : 106-109

Aristida tovariana Harol Gutiérrez , sp. nov. ( Figs. 1–2 )

Aristida tovariana differs from A. achalensis in having a smaller lemma 5–6 mm long with awns 5.8–10 mm long, and a fusiforme caryopsis with a ventral groove.

Type: — PERU. Ayacucho: Cangallo, Morochucos, Puna grasslands with rocks, 8.6 km SW of Condorcocha village, 13°30’30.92”S, 74°49’6.44”W, 3380 m, 2 May 2014, C. Tejada 332 (holotype HSP!).

Erect, densely tufted, wiry, perennials. Culms 15–20 cm tall, unbranched or weakly branched near the base. Leaves usually all basal; leaf sheaths glabrous; ligules 0.3–0.4 mm long, a line of hairs, with a variable number of long white cilia near the margins, the cilia 2–3 mm long; leaf blades 4–12 cm long, 0.3–0.4 mm wide, tightly involute, glabrous adaxially, scaberulous abaxially, curling when dry, apically acute, the basal blades 1/3–1/2 as long as the culm. Inflorescence an erect, weakly branched or unbranched narrow panicle, panicles 4–6 × 0.8–1 cm with 6–18 spikelets; panicle branches usually erect, glabrous to distally scaberulous, the axes scabrous or scaberulous. Spikelets 1–1.5 cm long, weakly laterally compressed, disarticulating above the glumes, greenish purple when young, 1-flowered; glumes 7–10 mm long, lanceolate, unequal, membranous, 1-veined, keeled, glabrous, the keels scabrous; lower glumes 7–8.5 mm long, unawned, mucronate or with an awn up to 1.2 mm long; upper glumes 7–10 mm long, unawned, mucronate or with an awn up to 1.8 mm long; floret as long as the spikelet, terete; callus 0.8–1 mm long, obtuse, hairy, the hairs 0.1–0.3 mm long; lemma 5–6 × 0.5–0.8 mm, cartilaginous, terete, 3-awned, the awns unequal and fused at base to form the column with no articulation, lateral awns 5.8–6 mm long, usually shorter than the central awn, central awn 8–10 mm long, scaberulous, column 2–2.5 mm long, twisted 2–3 times; paleas 0.9–1 mm long, 2-veined, membranous, hyaline; lodicules 2, 1–1.1 mm long, membranous, hyaline; stamens 3, anthers 0.9–1 mm long. Caryopses 4–4.2 × 0.3–0.4 mm, fusiform with a ventral groove, the embryo 1/3 the length of the caryopsis.

Ecology and distribution —Cultivated areas with sandy soil, in the inter-Andean valleys, at 3380 m in southern Ayacucho ( Figs. 3–4 ), occurring with A. adscensionis Linnaeus (1753: 82) and A. asplundii Henrard (1926: 42) . The new species is common in the area, occuring in two densely populations.

Etymology —The new species is named after Oscar Tovar Serpa (1923–2009), famous Peruvian botanist and agrostologist who published many taxonomic treatments on the grasses of Peru.

Discussion: — Aristida tovariana is morphologically similar to A. achalensis Mez (1921:149) , in having a contracted, spiciform panicle with appressed spikelets and lemma with twisted column without articulation. The new species differs from A. achalensis in having smaller spikelets (1.0– 1.5 cm vs. 2.5–3.5 cm), larger panicles (9–45 × 1–3 cm vs. 4–6 × 0.8–1 cm), glabrous lemmas (vs. scabrous) and longer lemmas ((9–)11–15(–17.5) mm vs. 5–6 mm long). The awns in both species are unequal, filiform, straight, more or less divergent, and scabrous. However, A. tovariana has shorter central and lateral awns. The central awns are 14–27 mm long in A. achalensis and 8–10 mm long in A. tovariana while the lateral awns are 10–23 mm long in A. achalensis and 5.8–6 mm long in A. tovariana . The anthers of A. achalensis are 1.4–2 mm long and the anthers of A. tovariana are 0.9–1 mm long. In addition, the caryopsis of A. achalensis lacks a ventral groove.

Conservation status —Considering the IUCN (2010) criteria, the assigned conservation status is Vulnerable (VU) under criteria D2, with an area of occupancy (AOO) <20 km 2 and a number of localities ≤ 5.

Additional material examined: — PERU. Ayacucho: Cangallo, Morochucos, Puna grasslands near Mayobamba river with “quinua” crops, 13°30’29”S, 74°49’6”W, 3402 m, 18 February 2018, H. Gutiérrez & R. Castañeda 161 ( USM) ; 13°30’30.90”S, 74°49’4.30”W, 3397 m, 18 February 2018, H. Gutiérrez & R. Castañeda 164 (topotype USM) .

Figures

FIGURE 1. Aristida tovariana (drawn from the holotype). A. Habit, B. Portion of involute leaf blade, C. Glumes (lower and upper), D. Lemma with column and awns, E. Caryopsis (hilum view), F. Caryopsis (scutellum view), G. Palea. Illustration by D. Cossios.

FIGURE 2. Type locality of Aristida tovariana in Ayacucho, Peru.

FIGURE 3. Inflorescences of Aristida tovariana at the type locality: Cangallo, Morochucos, Ayacucho, Peru; 3300 m. Photograph by R. Castañeda, February 2018.

FIGURE 4. Habitat of Aristida tovariana in hydromorphic soil, at the type locality: Cangallo, Morochucos, Ayacucho, Peru; 3300 m. Photo by R. Castañeda, February 2018.