Cestrum lentii A.K.Monro, 2012

Monro, Alex K., 2012, Eight new species of Cestrum (Solanaceae) from Mesoamerica, PhytoKeys 8, pp. 49-82 : 68-70

Cestrum lentii A.K.Monro sp. nov. Fig. 8 A-D

Diagnosis.

Most similar to Cestrum johnniegentrianum D’Arcy from which it can be distinguished by the secondary nerves of the lower leaf surface which are dark relative to the leaf lamina, the longer inflorescences bearing larger bracteoles and flowers with larger calyces.

Type.

Costa Rica. Cartago: 8 km SE of Tapantí, 09°43'54"N, 083°46'43"W (DMS), 1500 m, 18 Jun 1967, R. W. Lent 1051 (holotype: MO-3279022).

Description.

Unbranched shrub to 1.0-1.5 m. Leaf-bearing stems grey-tan to pale brown, the internodes 20-67 × 3.5-8.0 mm; young stems glabrous. Axillary buds 2.5-7.0 mm, brown, densely pubescent, not subtended by a minor leaf. Lamina 130-200 × 70-98 mm, length width ratio 1.7-2.4, broadly ovate, elliptic or broadly obovate, chartaceous or subcoriaceous, brown, green-grey; upper surface glabrous, primary and secondary veins clearly visible to the naked eye, primary and secondary raised; the lower surface glabrous, primary to quarternary, primary to quinternary veins clearly visible to the naked eye, primary and secondary veins raised, the veinlets visible, unbranched, secondary veins 7-10 pairs, 45-60° to the midrib, curved, weakly curved, ascending; base decurrent, cuneate-obtuse, cuneate-decurrent; margin irregularly entire, minute crenate to sinutae; apex cuspidate, subcuspidate; petioles decurrent on the stem, 17-30 × 1.5-2.5 mm, dark brown, yellow-brown, tan-cream, glabrous. Inflorescences 4-15 per herbarium sheet, axillary, panicles solitary in each axil, along the full length of leaf-bearing stems and below, 25-30 mm long, bearing 5-9 flowers borne in a panicle of 2-3 clusters of flowers with reduced branches, each flower cluster bearing 1, 3-6 flowers; peduncle 3-12 × 0.75-1.0 mm, dark brown, sparsely pubescent, the hairs 0.250-0.375 mm, branched, dendritic, eglandular; bracts absent; bracteoles 3-6 mm, linear, spathulate, sparsely pubescent. Flowers pedicellate, the pedicels 0.50-0.75 mm; calyx 4.0-4.5 × 2.0-3.5 mm, the outer surface glabrous, the lobes 5, 1.25-1.75 mm long, weakly spreading; corolla green (in bud), 15-17 mm long, the tube ca. 13.5 mm long, ca. 1.5 mm in diameter at the mouth, 0.75 mm at the base, glabrous, the lobes 5, 4 mm long; stamens 5, the filaments ca. 13 mm long, equal, adnate for 12 mm, with a lobe-like appendage present at insertion point, pubescent from insertion point to the base, the anthers ca. 1.375 × 1.0 mm; style ca. 13 mm, the stigma ca. 0.75 × 1.0 mm. Infructescences 15-25 mm long, bearing 5-8 fruit; fruiting calyx ca. 3 × 4 mm; fruit immature, colour when ripe unknown. Seeds 6, mature seeds not seen.

Etymology.

This species is named after the US collector of the holotype Roy Lent (1931-), who worked for F in Costa Rica.

Distribution.

Wet premontane forest from 1100 to 1700 m on Pacific and Caribbean drainage of the Talamanca Mountains, Costa Rica and Panama. Cestrum lentii is known from two localities ca. 210 km apart at the eastern (La Fortuna, Chiriquí, Panama) and western ( Tapantí, Cartago, Costa Rica) ends of the Talamanca Mountains. It is likely that populations of Cestrum lentii connect these localities and that the absence of records is a reflection of sampling effort. Assuming that Cestrum lentii is found throughout the Talamanca Mountains between altitudes of 1100 to 1700 m then an estimated Area of Occupancy for this species is 5,880 km2 ( Google Earth, accessed June 17, 2011, images 2001, 2003, 2006, 2009).

Discussion.

None of the four known collection of this species had been determined to species prior to this study. A comparison of the holotype and paratype material with type specimens from the herbaria listed in the Materials and methods section recovered Cestrum lentii as most similar to Cestrum johnniegentrianum D’Arcy. It can be easily distinguished from this species based on leaf and inflorescence morphology as summarised in Table 14 .

Conservation status.

Using IUCN criteria ( IUCN 2001) Cestrum lentii is considered to beNear Threatened (NT)under IUCN (2001). The Extent of Occurrence for Cestrum lentii is calculated to be 5,880 km2 (criteria B1, <20,000km2, Vulnerable) and it is known from only two localities (B1a, ≤5) both of which are protected. Field experience at these localities suggests that the habitat of this species is not under any imminent threat. Illegal mining activity and planned hydroelectricity dam projects in the area may, however, result in habitat loss in the medium-term to long-term which would result in this species being assessed as Vulnerable. For this reason Cestrum lentii is considered Near Threatened.

Paratypes.

COSTA RICA. Cartago: Tapantí Hydroelectric Reserve, trail along Río dos Amigos, 09°41'24"N, 083°47'24"W (DMS), 1600-1700 m, 23 Jun 1976, T. B. Croat 36199 (MO). PANAMA. Chiriquí: Fortuna Dam area, between Quebrada Los Chorros and Quebrada Hondo, to N of reservoir, in forest N of road, 08°45'N, 082°14'W (DMS), 1100 m, 20 Sep 1984, H. W. Churchill & A. Churchill 6172 (MO); Fortuna Dam area, between Quebrada Los Chorros and Quebrada Hondo, to N of reservoir, in forest N of road, 08°45'N, 082°14'W (DMS), 1100 m, 20 Sep 1984, H. W. Churchill & A. Churchill 6179 (MO).

Figures

Figure 8. Cestrum lentii A. K. Monro A Flowering stem B Flower C Longitudinal section through the corolla showing stamen arrangement D Style. Drawn from R. W. Lent 1051 (MO).