Larnax pumila S. Leiva, Barboza & Deanna, 2014

Larnax pumila S. Leiva, Barboza & Deanna View in CoL , sp. nov. ( Figs. 3 A, E View FIGURE 3 , 5 View FIGURE 5 , 6 View FIGURE 6 )

Type:— ECUADOR. Pastaza: Mera, rumbo hacia Río Anzú, sendero , 1340 m, 78°04'01.5''W, 01°25'31.6''S, 13 November 2011 (fl, fr), C. I. Orozco, G. E. Barboza, A. Orejuela & S. Leiva 3890 (holotype CORD 0006758 ! GoogleMaps , isotypes COL! GoogleMaps , QCA! GoogleMaps ).

Larnax pumila differs from L. andersonii in its glabrous leaves above (vs. strigose leaves above in L. andersonii ), its shortly mucronate anthers (vs. apiculate anthers), its oblique to pendent fruiting pedicels (vs. erect fruiting pedicels), and in its white to cream mature berry (vs. orange berry); it also differs from L. dilloniana in being a lower shrub (0.5–1 m tall vs. 0.7–3 m tall in L. dilloniana ), in having smaller dimorphic leaves (the larger ovate 7.2–9.6 cm long and, the smaller cordate 2.4–2.7 cm long vs. elliptic leaves 9–16.3 cm long in L. dilloniana ), and in its 1–3 flowered inflorescence (vs. 3–6- flowered).

Shrubs, widely branched, plagiotropic, 0.5–1 m tall. Stems terete with two ribs slightly marked, hollow, glabrescent, with long simple antrorse multicellular non-glandular trichomes; old stems 6–8 (–10) mm wide at base, green, sometimes purple, without lenticels, with longitudinal short fissures; young stems green, sometimes purple above, green below, or completely deep purple; nodes generally deep purple. Leaves alternate, distal leaves sometimes geminate; petiole semi-terete, (0.9–) 2–2.7 (–3) cm long, deep purple above, green or partially purple below; leaf blade entire, fleshy, bright green and glabrous above, light green and glabrescent to pubescent below, slightly sericeous with the same trichomes of the stems and petioles mainly along veins, and with some short, ochraceous glandular trichomes occasionally on the surface, the major leaf ovate, apex acuminate, base unequal, 7.2–9.6 cm long, 3.7–5.6 cm wide; the minor leaf cordate, apex short acuminate, base oblique, 2.4–2.7 cm long, 1.9–2.2 cm wide. Fascicles axillary, 1–3-flowered; pedicels (4–) 5–7 mm long, light-green, filiform, pendent, pubescent, with short antrorse multicellular non-glandular trichomes. Flowering calyx (2.9–) 3.5–4.5 mm diameter in anthesis, light green with dark green veins externally, light-green internally, cup-shaped, fleshy, pubescent, slightly sericeous externally, with abundant short glandular trichomes (stalk unicellular, ochraceous head 6-celled), glabrous internally; protruding main veins with long transparent non-glandular trichomes; tube 1.7–2.1 mm long, (2.7–) 3–4 mm diameter; lobes minute, (0.2–) 0.3–0.5 mm long, 0.2–0.4 mm wide, unequal, shortly triangular, acute, erect, with papillae and 2–3 celled transparent non-glandular trichomes at the apex. Corolla slightly campanulate before anthesis, clearly stellate in anthesis, (6–) 7–9 mm diameter in anthesis, fleshy; tube yellowish green on both sides, 1.7–2.2 mm long, (3–) 3.5–4.1 mm diameter, glabrescent externally, with short glandular trichomes, glabrous internally; lobes (5.5–) 7–9 mm long, (2–) 2.7–2.9 mm wide, triangular, erect or expanded, rarely slightly reflexed, opaque and cream externally, lustrous and deep-purple internally with yellowish green apex, margins and veins, margin ciliate, glabrescent externally, with short glandular trichomes, slightly sericeous internally, with short non-glandular and glandular trichomes; inner annular ring of trichomes absent. Stamens exserted, heterodynamous; filaments glabrous, cream, three longer (1–1.2 mm long), two shorter (0.8–1 mm long), filament base expansion auriculate, yellowish-green, 1–1.1 mm long, auricles conspicuous; anthers 2–2.2 mm long, 1.5–1.6 mm wide, deep purple to dull purple, ellipsoidal, shortly mucronate, connective cream to dull purple, narrowly elliptical. Ovary green, glabrous, ovate, subglobose, 1.2–1.4 mm long, 1.2–1.3 mm wide, nectary annular, greenish yellow, occupying 30–40% of the ovary length; style 3.6–3.9 mm long, glabrous, cream, slightly broadened at the apex, extending ca. 0.7 mm beyond the anthers; stigma clavate, subbilobate, light green to tan, 0.3–0.35 mm long, 0.4–0.5 mm diameter. Fruit a berry, globose or subglobose, 8–10 mm long, 7–8 mm diameter, cream to white when mature, green when immature, fleshy, glabrous. Fruiting calyx accrescent, loosely enveloping the berry, 20–22 mm long, 15–17 mm diameter, open at the apex, lustrous, invaginate-pyriform-plicate, green with dark green ribs, pubescent with abundant short glandular trichomes (stalk unicellular, ochraceous head 6-celled), occasionally with some short, transparent, non-glandular trichomes mainly along veins externally, glabrous internally; lobes conspicuous, ca. 1 mm long. Fruiting pedicels 11–13 mm long, green, oblique to pendent, glabrescent. Seeds 50–60 per fruit, 2.5–2.7 mm long, 2–2.2 mm diameter, brown, reniform, glabrous; testa foveolate. Embryo curved.

Etymology: — This species is named due to its distinctive habit, which is one of the lowest species of the genus.

Phenology: — Flowering from April to January, and fruiting from November to January.

Distribution and Ecology: — Found on margins of the Anzu, Plata, and Tena rivers in the Pindo-Mirador reserve and in the environs of Mera (Napo, Pastaza). Larnax pumila is distributed on the eastern slopes of the Andes Mountains, always along the course of rivers or streams ( Fig. 4 View FIGURE 4 ). It inhabits primary cloud forest from 400 to 1400 m elev.

Species conservation assessment: — According to IUCN criteria ( IUCN 2012), L. pumila is considered as Near Threatened (NT). The extent of occurrence is calculated to be ca. 100 km 2 (Criterion B1 <5000 km 2, Endangered) and the species is known from only four localities (Criterion B1a ≤5, Endangered). However, no decline in geographic range or fragmentation of the habitat has been observed and so this assessment has been regarded as Near Threatened. More collecting and population assessments would help to confirm this assessment.

Additional specimens examined: — ECUADOR. Napo-Pastaza: Napo, Tena, forested bank of Rio Tena , 400 m, 8 April 1935 (fl), Mexia 7195 ( US!, UCR!) . Pastaza: Mera, Colonia Pindo Mirador, en la Reserva Pindo-Mirador, Río Plata , 1230 m, 12 November 2011 (fl, fr), Orozco et al. 3878 ( CORD!, COL, QCA, HAO) ; Mera, 9,3 km desde la Plaza Mayor de Mera hacia Cavernas del Río Anzú (vía hacia las antenas) , en borde de riachuelo, bosque primario, 1332 m, 01°25’32.2’’S 78°04’00.1’’W, 24 January 2013 (fl, fr), Deanna & Leiva 113 ( CORD!, QUSF!) GoogleMaps ; environs of Mera, forest remnants above town, 1200 m, 22 November 1974 (fl, fr), Plowman & Davis 4505 ( GH, USM!, MO, K) ; vicinity of Shell, 1.2 km N of town, disturbed virgin forest in swampy area, 1092 m, 01°29’33’’S 78°03’57’’W, 9 May 2003 (fl), Croat et al. 88868 ( QCNE!; MO) GoogleMaps .

Discussion: — Larnax pumila is distinctive by its small and characteristically plagiotropic habit, its leaf dimorphism (larger leaf ovate; smaller leaves cordate, Fig. 6 A View FIGURE 6 ), and its white to cream berry loosely enclosed by the invaginate-pyriform-plicate fruiting calyx ( Fig. 6 C View FIGURE 6 ).

Larnax pumila is most similar to the sympatric L. andersonii , the two species occuring in Pastaza Province ( Ecuador). Both have a flowering calyx with minute lobes <1 mm long and accrescent fruiting calyx loosely enveloping the berry, but L. pumila can immediately be distinguished by its indumentum, anthers, fruiting pedicels and berries as summarised in Table 3.

In addition, Larnax pumila is superficially similar to L. dilloniana S. Leiva, Quipuscoa & N. W. Sawyer (1998: 85) from northern Peru. Both species have an internally glabrous corolla of the same colour, and an invaginate-pyriform-plicate fruiting calyx loosely enveloping the berry ( Fig. 6 A–C View FIGURE 6 & Fig. 13 B, C View FIGURE 13 ). Larnax pumila differs from L. dilloniana in its height, leaf size, and number of flowers per inflorescence ( Table 4, Figs. 6 A View FIGURE 6 , 13 A–C View FIGURE 13 ). According to L. dilloniana distribution cited by Leiva et al. (1998a), this species would be sympatric with L. pumila . Leiva et al. did not cite any specimens for Ecuador and after a careful revision of the Ecuadorian herbaria and others where collections from Ecuador are housed (AAU, CORD, HUT, NY, Q, QCA, QCNE, QPLS, QUSF, S, USM) and extensive fieldwork we also did not find L. dilloniana in Ecuador.