Xiphidium pontederiiflorum M. Pell., Hopper & Rhian J. Sm., 2020

Pellegrini, Marco O. O., Hickman, Ellen J., Guttierrez, Jorge E., Smith, Rhian J. & Hopper, Stephen D., 2020, Revisiting the taxonomy of the Neotropical Haemodoraceae (Commelinales), PhytoKeys 169, pp. 1-59 : 1

5.2. Xiphidium pontederiiflorum M. Pell., Hopper & Rhian J. Sm. sp. nov. Fig. 26

Diagnosis.

Similar to Xiphidium caeruleum Aubl. in habit and inflorescence morphology, differing due to its leaves marginally ciliate at apex, apricot to light orange flower buds, larger and zygomorphic flowers, inner lobes obovate with obtuse to round apex, upper tepals connate in the basal third or halfway through with three orange-yellow to orange nectar guides, dark red to vinaceous mature capsules and dark reddish-brown to reddish-black seeds.

Type.

Ecuador. Esmeraldas: Lita, Río Lita and tributaries, 120 km NW of Ibarra, 14 km of Lita, fl., fr., 7 May 1987, D.C. Daly & P. Acevedo-Rodríguez 5142 (US!; isotype: NY!).

Description.

Herbs ca. 35-185 cm tall, perennial, rhizomatous with a definite base, terrestrial to paludal in boggy areas. Roots thin, fibrous, brown, sand-binding, emerging from the rhizome. Rhizomes underground, long, trailing, external surface brown to reddish-brown, internal surface reddish-orange to red. Stems ascending to erect, fibrous, unbranched; internodes 4.3-7 cm long, green, glabrous to sparsely tomentose, hairs pilate, white. Leaves distichously-alternate, equitant, evenly distributed along the stems, sessile, the apical ones gradually smaller than the basal ones; sheaths 0.6-2.2 cm long, light green, glabrous to sparsely tomentose, margin ciliate, hairs pilate, white; blades 18.7-47.3 × (0.9-1.6-)2.4-5 cm, fibrous, succulent, unifacial, medium green, drying olive-green to brown, linear-elliptic to narrowly elliptic, slightly ensiform to ensiform, glabrous, base sheathing, margins green, glabrous to ciliate at the apex, apex acuminate; midvein inconspicuous, secondary veins 5-8, slightly impressed to impressed, becoming more prominent when dry. Inflorescences terminal, solitary, consisting of a pedunculate many-branched thyrse; peduncles (1.5-)2.4-7.8 cm, sparsely tomentose to densely tomentose, hairs pilate, white; basal bract 5-5.7 × 0.4-0.5 cm, leaf-like, linear-elliptic, slightly ensiform to ensiform, glabrous or sparsely tomentose at base, hairs pilate, white, base truncate to slightly sheathing, margin ciliate at apex, apex acuminate, secondary veins inconspicuous; cincinnus bract 2.8-4.4 × 1.2-4 mm, broadly triangular to narrowly triangular, green, glabrous to sparsely tomentose, hairs pilate, white, base truncate, margin ciliate, apex acuminate; cincinni (9-)12-41 per thyrse, alternate, 3-18-flowered, peduncle 0.3-1.7 cm long, green, sparsely tomentose to densely tomentose, hairs pilate, white; bracteoles 0.8-1.3 × 0.6-1 mm, broadly triangular to broadly depressed ovate, green, glabrous to sparsely tomentose, hairs pilate, white, base amplexicaulous, non-perfoliate, margin glabrous, apex acute. Flowers 1.9-2.7 cm diam., bisexual, chasmogamous, enantiostylic, campanulate, asymmetric due to the position of the style; floral buds 4.8-6 × 2.2-3 mm, ovoid, apricot to light orange; pedicels (2-)5.1-7.3 mm long, upright and slightly elongate in fruit, green, tomentose to densely tomentose, hairs pilate, white; perianth zygomorphic, lobes free, except for the upper 3 lobes which are connate on the basal third to mid-length, nectar guide orange-yellow to orange on the basal third of the connate lobes, with an apical black mucron, outer lobes 8.5-13.1 × 3.5-4.7 mm, subequal, the upper slightly shorter, narrowly obovate to obovate, external surface apricot to light orange, rarely white, glabrous to sparsely tomentose, hairs pilate, white, internal surface white, glabrous, base cuneate, margins glabrous, apex acute- to obtuse-mucronate, mucron dark brown to black, inner lobes 9.7-13.2 × 4.8-7.3 mm, subequal, the lower slightly narrower and cucullate, obovate to broadly obovate to broadly obtrullate, external surface white to apricot, rarely light orange, glabrous, internal surface white, glabrous, base cuneate, margins glabrous, apex obtuse- to round-mucronate, greenish-yellow to apricot, mucron dark brown to black; stamens 3, lateral stamens with filaments 1.6-1.8 mm long, straight, basally cream to apricot, apically white, glabrous, anthers 1.4-1.7 × 0.6-0.9 mm, dorsifixed, introrsely rimose but functionally poricidal, broadly oblongoid to sagittate, yellow, medial stamen with filament 3.7-4.3 mm long, bent upwards, basally cream to apricot, apically white, glabrous, anthers 2-2.4 × 0.7-1.1 mm, dorsifixed, introrsely rimose but functionally poricidal, broadly oblongoid to sagittate, yellow; ovary 1.8-2.2 × 1.7-2 mm, broadly ellipsoid to globose, 3-loculate, green to red to vinaceous, smooth, densely tomentose between the locules, style 5.6-8.3 mm, bent upwards, basally cream to apricot to light orange, apically white, glabrous, stigma crateriform, white, papillose. Capsules 5.2-7.4 × 5.8-8 mm, subglobose to globose, somewhat fleshy, medium green to dark red when immature, dark red to vinaceous when mature, glabrous, indehiscent. Seeds 0.78-0.84 × 0.65-0.67 mm, cuboid to polygonal, each face sunken, testa dark reddish-brown to reddish-black, tuberculate; embryotega dorsal, relatively inconspicuous, without a prominent apicule; hilum punctate.

Specimens seen

(paratypes). Colombia. Antioquia: Frontino, km 23 of road Nutibara/La Blanquita, region of Murrí, fl., fr., 4 Nov 1988, J.L. Zarucchi et al. 7140 (MO, US). Guarira: Sierra Nevada de Santa Marta, entre Riohacha y Pueblo Viejo, fr., 7 Feb 1959, H.G. Barclay & P. Juajibioy 6838 (US). Putamayo: road from Sibundoy to Mocoa, fl., fr., 15 Mar 1953, R.E. Schultes & I. Cabrera 18823 (GH, U, US); Intendencia of Putamayo, steep roadside slopes along road from Mocoa towards Sibundoy, fl., fr., 27 Jan 1976, J.L. Luteyn et al. 5062 (F, NY, US). Valle del Cauca: km 100, on Cali/Buena-Ventura highway, fl., fr., 5 Dec 1946, O. Haught 5324 (US). Vaupés: Puerto Hevea, confluence of Macaya and Ajaju rivers, fl., Jul 1943, R.E. Schultes 5654 (GH, US). Ecuador. El Oro: 11 km West of Pinas, on the new road to Santa Rosa, fl., fr., 8 Oct 1979, C.H. Dodson et al. 9012 (SEL, US); Pichincha: virgin forest along Río Toachi near Santo Domingo, fr., 3 Aug 1962, C. Jativa & C. Epling 322 (US). Panama. Colón: Canal Zone, Las Cascadas Plantation, near Summit, fr., 2 Dec 1923, P.C. Standley 25671 (US); hills north of Frijoles Station, fr., 19 Dec 1923, P.C. Standley 27414 (US); Gamboa, fr., 26 Dec 1923, P.C. Standley 28397 (US); near Fort Randolph, fr., 28 Dec 1923, P.C. Standley 28734 (US). Darien: Cerro Pirre, fr., 9-10 Aug 1967, J.A. Duke & T.S. Elias 13747 (GH, US); Río Chico, from Yaviza at junction with Río Chucunaque to ca. 1 hour by outboard from junction, fr., 19 Dec 1966, D. Burch et al. 1096 (GH, K, NY, UC, US). Panamá: Río La Maestra, fr., 4 Dec 1936, P.H. Allen 67 (MO, US). Panamá Oeste: Capira, about 50 km southwest of Panama City, fl., fr., Sep 1932, B. Paul 141 (US).

Etymology.

The epithet refers to the similarity between our new species’ floral morphology and some species of Pontederia s.lat. ( Pellegrini et al. 2018).

Distribution and habitat.

Xiphidium pontederiiflorum is known to occur in Colombia, Ecuador, and Panama (Fig. 27 ), in the understorey in rainforests, generally near rivers, along streams, and other water bodies.

Phenology.

Blooms and fruits from March to August.

Conservation status.

Xiphidium pontederiiflorum possesses a relatively narrow EOO (849,856 km2) and AOO (ca. 132 km2). Thus, following IUCN’s (2001) recommendations, X. pontederiiflorum should be considered as Endangered [EN, A2ac+C2a(i)].

Comments.

Xiphidium pontederiiflorum is morphologically similar to X. caeruleum in overall habit and inflorescence morphology. However, X. pontederiiflorum can be differentiated by its leaves marginally ciliate at apex (vs. glabrous in X. caeruleum ), apricot to light orange flower buds (vs. white to cream, rarely apricot in Mexican populations), larger and zygomorphic flowers (vs. smaller and actinomorphic flowers), inner lobes obovate with obtuse to round apex (vs. elliptic with acute apex), upper tepals connate in the basal third or halfway through with three orange-yellow to orange nectar guides (vs. only basally connate and lacking nectar guides, rarely with green nectar guides in some Costa Rican populations), capsules dark red to vinaceous when mature (vs. orange to medium red) and dark reddish-brown to reddish-black seeds (vs. black). Added to that, X. pontederiiflorum is generally a more robust plant, growing erect up to 2 m tall, while X. caeruleum reaches up to 1 m tall, and its stems tend to lean due to the plant’s weight, especially when in bloom or fruit.

Xiphidium pontederiiflorum was first collected in 1923 in Panama by the pioneering Neotropical botanist P.C. Standley (1884-1963) from the United States ( Williams 1963). Reference to it was included under X. caeruleum in Standley’s (1928) Flora of the Panama Canal Zone.

Figures

Figure 26. Xiphidium pontederiiflorum M. Pell. et al. A-C habit: A vegetative habit B flowering habit with a young inflorescence C viviparous inflorescence with three axillary propagules D inflorescence with open flowers and apricot floral buds E floral buds and flowers at pre-anthesis F, G flower: F white flower with green ovary G pale apricot flower with vinaceous ovary H detail of the androecium and gynoecium, showing the ovary pubescence along the septal ridges I inflorescence with open flowers and mature berries J mature berry. C, E, J by A. R. Jonker, remaining photos by A. Kay.

Figure 27. Distribution of Xiphidium pontederiiflorum M. Pell. et al. Light Green - Subtropical Coniferous Forests; Red - Deserts, Xeric Shrublands and Tropical Coniferous Forests; Orange - Tropical / Subtropical Grasslands, Savannahs and Shrublands; Maroon - Dry Broadleaf Forests; Green - Moist Broadleaf Forests; Lilac - Montane Grasslands and Shrublands.