Bromus picoeuropeanus Acedo & Llamas, 2019

Acedo, Carmen & Llamas, Felix, 2019, A new species of perennial Bromus (Bromeae, Poaceae) from the Iberian Peninsula, PhytoKeys 121, pp. 1-12 : 1

Bromus picoeuropeanus Acedo & Llamas sp. nov.

Type.

Spain. Cantabria: Macizo Oriental de Picos de Europa, Vegas de Ándara: Fuente de la Escalera. 43°12.42'N, 4°42.20'W, [WGS-84], on limestone dry rocky sites, moving by gelifraction, 1869 m alt., 31 August 2011; C. Acedo, A. Alonso & F. Llamas CA247.4 (Holotype LEB 121814).

Diagnosis.

Bromus picoeuropeanus differs from B. erectus Huds. (Table 1 ) in having shorter habit; longer creeping rhizomes; non-cauline leaf blades short and never reaching the inflorescence, flat and similar to the cauline leaves; ligule truncated or round up to 1 mm; panicle 3-5(8) cm, contracted and smaller, with few spikelets, up to 11; all branches shorter than the spikelets; caryopsis thickened, inrolled or plicate, 8-9 mm, shorter than palea. B. picoeuropeanus also differs in its preference for stony soils.

Description.

Perennial plant with long rhizomes 3-5(7) cm, loosely tufted. Flowering culms up to 40 cm. Culms channeled and glabrous, with glabrous nodes. Extravaginal innovation leaves with short blades, similar to the cauline leaves. Leaf sheaths of cauline leaves glabrous. Old basal leaf sheaths persistent, investing the culm base. Blade of cauline leaves 9-13 cm × 2-3 mm, tapering gradually towards the apex. Ligule membranous and glabrous, short, 0.5-1 mm, apex truncated or rounded, ± lacerated. Panicle 3 –4(– 8) × 2-3 cm, erect, lax, contracted, with 4-8(11) spikelets, branches slender. Scale of the lower node leaf-like, c. 4 mm, glabrous. Pedicels scabrid with fine antrorse teeth. All branches and pedicels shorter than spikelets. Spikelets 16 –22(– 25) × 3-5 mm, with two unequal glumes and 4 –5(– 7) fertile florets, imbricate when young, in maturity the florets slighted separated. Lower florets bisexual, 9 –11(– 12) mm, oblong, scaberulous toward the apex; upper floret male or sterile, 5-6 mm, lanceolate, glabrous, similar in color and texture to the lower florets. Lower glume 1-veined, narrow, 6-7 mm. Upper glume 3-veined, 7-9 mm. Lemma glabrous, lanceolate, section slightly keeled, 9 –11(– 12) mm (excluding the awns), 3-5-veined. Apex of the lemma slightly emarginate (sinus approximately 0.1 mm); margin rounded. Awn short, (2.5-) 3-4 (-5) mm, up to 1/3 the lemma length, fine and straight, inserted 1-1.5 mm below the apex. Rhachilla 2-3 mm, scabrid with very fine antrorse teeth. Callus short, glabrous and rounded. Palea linear-lanceolate of similar size or slightly shorter than the lemma, 8-11 × 1-2 mm, with aculeolate keels; wings nearly as wide as the palea body, with smooth border. Lodicules 2, lanceolate to oblong, glabrous, 0.5-1.5 mm long. Stamens 3, with anthers 3.5-4.5 mm long. Caryopsis elliptic, enrolled or plicate at maturity, 7-8 mm, shorter than palea (Fig. 1 ).

Phenology.

Flowering July - August. Fruiting August - September.

Distribution and habitat.

Bromus picoeuropeanus is endemic to the Iberian Peninsula and occurs in Spain, distributed through the Northern Mountains of the Cantabrian Range (Fig. 2 ). We collected it in several localities of Picos de Europa National Park, growing in dry rocky areas of limestone moving by gelifraction, and on stony areas at an altitude of 1600-2200 m.

Conservation status.

Bromus picoeuropeanus occurs within the Picos de Europa National Park. Although the IUCN (2017) criterion B thresholds (EOO = 111.51 km2; AOO = 40.0 km2) suggest a different category [EN], the species has been evaluated DD (Data Deficient), because further study is needed to assess the risk.

Etymology.

The specific epithet is a reference to the Spanish National Park Picos de Europa, where it was collected.

Figures

Figure 1. Bromus picoeuropeanus. A Habit showing the developed rhizomes, the short basal leaves, and the contracted inflorescence B Spikelet with unequal glabrous glumes and five florets C Glumes D Palea in adaxial view, showing the two adaxial wings E Lemma in lateral view (drawn from the holotype) F Caryopsis in adaxial and abaxial view (drawn from LEB 121815). Drawings by Ms. Giulia Osti, 2018.

Figure 2. Distribution map representing all the known locations of Bromus picoeuropeanus.