Aulonemia prolifera P.L. Viana & Filg., 2014

Aulonemia prolifera P.L. Viana & Filg. View in CoL , sp. nov. Figs. 3−4 View FIGURE 3 View FIGURE 4 .

Similis Aulonemiae soderstromii rhizomatibus amphipodialibus, culmis solidis et spiculis linearibus, muticis, sed fimbriis secus vaginae margines (x vaginis glabris aut ciliatis in A. soderstromii ) et fimbriis erectis ad vaginae apicem (x fimbriis effusis in A. soderstromii ) differt.

Type:— BRAZIL. Espírito Santo: Castelo, Parque Estadual do Forno Grande , 1200 m, 27 January 2004, L. Kollmann 6386 (holotype MBML! , isotype BHCB! ).

Rhizomes amphipodial. Culms initially erect, decumbent or creeping, densely aggregated, the erect ones becoming clambering on the neighboring vegetation, 1.5–10 m long, the decumbent and creeping ones forming new shortnecked sympodial rhizomes on nodes in contact with the ground, then becoming leaning on the adjacent vegetation; midculm internodes 8–35 × 0.3–0.8 cm, solid or with a few diffuse air canals, terete, glabrous, seldom sparsely puberulous, green to brownish, maculate, surface smooth to slightly papillose. Nodal line horizontal, glabrous; intranodal area 0.5–1.3 × 0.5–1.0 cm, glabrous; supranodal ridge conspicuous; buds 3–9 × 3–6 mm, triangular, oval to oval-lanceolate, glabrous, cataphylls ciliate toward the apex. Branch complement consisting of a single branch, which may seldom bear branchlets on its basal nodes. Culm leaves gradually differentiating into foliage leaves toward the culm apex, sheaths 5.5—12 cm long, glabrous, fimbriate at one margin, green; fimbriae 1.2–4.5 cm long; outer ligule present, minute, inner ligule 0.4–0.8 mm long, membranous-ciliolate; pseudopetiole 1–1.9 mm, pubescent adaxially, glabrous abaxially; blades 6.3–12.5 × 1.8–3.3 cm, oval-lanceolate, reflexed to deflexed, glabrous to puberulous adaxially, glabrous abaxially. Foliage leaves with sheaths 5–14 cm long, glabrous, papillose, conspicuously fimbriate at one margin, slightly carinate toward the apex, greenish, not mottled, apical auricular extension absent; pseudopetiole 2–5 × 2–3.2 mm, pubescent adaxially, glabrous to pubescent abaxially, greenish to brownish; fimbriae persistent, (1–) 2.5–6.5 cm long, erect, straight to undulate, terete to slightly flattened toward the base, scabrous all along, free or rarely connate at the base, pale; outer ligule 0.1–0.2 mm long, membranous to membranous-ciliolate; inner ligule 0.5–1 mm long, membranous-ciliolate; blades 13–27 × 2.1–5.3 cm, lanceolate to oval-lanceolate, patent to rarely deflexed, glabrous on the adaxial surface, glabrous to sparsely pilose on the abaxial surface, chartaceous, regularly green on both surfaces, not tessellate, base asymmetrical, rounded to attenuate, apex long acuminate, margins antrorsely scabrous. Synflorescence (6–)12–23 × (4.5)– 11– 25.5 cm, oblong to pyramidal; branches divergent; peduncle glabrous; pedicel 2–17 × ca. 0.2 mm, glabrous. Spikelets consisting of 2 glumes, 2–4 fertile anthoecia and 0–1 apical rudimentary anthoecium, 1.7–4.2 × 0.2–0.4 cm, linear to linear-lanceolate, slightly compressed laterally; glume I 4.2–6.3 mm long, 7-nerved, glabrous to puberulous on both surfaces, indumenta denser toward the apex, mottled, becoming pale brown with age, apex acute, awnless; glume II 7.2–8.5 mm long, 7–9-nerved, glabrous to puberulous on both surfaces, indumenta denser toward the apex, mottled, becoming pale brown with age, apex acute, awnless; rachilla internodes 5–8.5 mm, glabrous; lemma 8.5–12.8 mm long, 7–9(–11)-nerved, glabrous to puberulous, trichomes denser toward the apex, mottled, apex acute, awnless; palea 9.2–12.8 mm long, 7–8-nerved, glabrous or puberulous between the keels, pale brown, apex acute to naviculate. Lodicules elliptic to oval-lanceolate, ciliate at the apex; anthers ca. 5 mm long, yellowish; ovary ca. 1 mm long, ellipsoid, glabrous. Fruit not seen.

Etymology: —The specific epithet refers to the proliferous propagation of this species via amphipodial rhizomes.

Comments: —This new species is an aggressive rapid-grower, typically found in clearings and forest borders. Its efficient horizontal propagation via amphipodial rhizomes allows the plants to form dense masses of culms shooting in all directions, forming an almost impenetrable curtain ( Fig. 4A View FIGURE 4 ).

The overall morphology and habit of Aulonemia prolifera suggest a close relationship with A. soderstromii . Both species present a similar pattern of propagation via amphipodial rhizomes and have solid culms, concolor leaf blades (uniformly green on both sides), open panicles with divergent branches, and linear to linear-lanceolate spikelets with awnless glumes and lemmas. However, these species can be easily distinguished by the morphology of the fimbriae in their leaves, a character of inestimable value for the taxonomy of the genus ( Clark et al. 2007, Viana 2010). In A. prolifera , the fimbriae in the ligular region are erect ( Figs. 3C View FIGURE 3 , 4C View FIGURE 4 ) and longer (2.5–6.5 cm vs. 0.8–2.5 cm in A. soderstromii ), and the leaf sheaths have distinctly pectinate-fimbriate margins, at least on the apical half of its length ( Figs. 3C View FIGURE 3 , 4D View FIGURE 4 ). On the other hand, A. soderstromii has a conspicuous cluster of effuse and spreading fimbriae, 0.8–2.5 cm long, restricted to the ligular region ( Figs. 5C View FIGURE 5 , 6D View FIGURE 6 ), with the sheath margins glabrous or ciliate. These species can also be differentiated by the size of some structures, such as the leaf blades (up to 27 cm in A. prolifera , and no larger than 24 cm in A. soderstromii ) and rachilla internodes (5–8.5 mm in A. prolifera vs. 4.2–4.9 mm in A. soderstromii ). In Brazil, A. prolifera is the only known species with fimbriate sheath margins, a trait quite common in Andean species ( Clark et al. 2007), including Aulonemia humillima ( Pilger 1905: 100) McClure (1973: 58) , A. patula ( Pilger 1898: 719) , A. robusta Clark & Londoño (1990: 356) , A. subpectinata ( Kuntze 1891: 760) McClure (1973: 61) and A. ximenae L.G. Clark, Judz. & C.D. Tyrrell in Clark et al. (2007: 3). Further comments on morphological relationships among A. prolifera and putatively related species ( A. aristulata , A. cincta and A. prolifera ) are found under Aulonemia cincta and summarized in Table 1 View TABLE 1 .

Distribution and habitat: — Aulonemia prolifera is known from Espírito Santo and Minas Gerais, occurring in seasonally semi-deciduous and evergreen forests. The populations were documented in forests associated with granite outcrops, as the type locality, the Forno Grande State Park, and the Caparaó National Park, where the species is found at elevations between 500 and 1200 m.s.m.

Phenology: —Flowering collections of A. prolifera were made in 1988 (Kreiger 23281 and 23343, in Caparaó National Park) and in 2004 (Leite 3982, in Açucena, Minas Gerais, and Kollmann 6386, 6986 and 7136, in Forno Grande State Park). Based on these collections, the estimated flowering cycle for this species is approximately 16 years.

Conservation: —Probably endangered, based on small extent of known occurrence and low number of locations: EN B1a. Although there are historical records of A. prolifera in the two conservation units (Caparaó National Park and Forno Grande State Park), its occurrence in Caparaó National Park was not confirmed in two attempts to locate it in 2006 and 2007 (Viana 2010). Considering that it flowered in 2004 (as documented by Kollmann’s and Leite’s collections), the individuals of A. prolifera in Serra do Caparaó were probably in the seedling stages in 2006 and 2007 and therefore not readily recognizable in the field. The possibility of local extinction after the gregarious flowering event in 2006 should be investigated, because no caryopses were found in the examined specimens.

Additional specimens examined: — BRAZIL. Espírito Santo: Castelo, Parque Estadual do Forno Grande , 1200 m, 4 September 2004 (fl), L. Kollmann & R.L. Kollmann 6986 ( MBML) ; idem, 30 October 2004 (fl), L. Kollmann et al. 7136 ( MBML) ; idem, Trilha para as piscinas , 20°31'10"S, 41°05'15"W, 1227 m, 17 July 2008 (veg), P.L. Viana et al. 3637 ( BHCB, RB) GoogleMaps . Minas Gerais: Açucena, próximo a PCH Barra da Pacie?ncia , 18°56'S, 42°29'W, 512 m, 15 October 2004 (fl), F.S.F. Leite 3982 ( BHCB, UWSP) GoogleMaps ; Alto Caparaó, Parque Nacional do Caparaó   GoogleMaps , 17 December 1988 (fl), L. Krieger 23281 ( BHCB, CEN, CESJ) ; idem, 17 December 1988 (fl), L. Krieger 23343 ( BHCB, CESJ, MO) .