Cestrum gilliae A.K.Monro, 2012

Monro, Alex K., 2012, Eight new species of Cestrum (Solanaceae) from Mesoamerica, PhytoKeys 8, pp. 49-82 : 59-61

Cestrum gilliae A.K.Monro sp. nov. Fig. 5 A-D

Diagnosis.

Most similar to Cestrum morae Hunz. from which it can be distinguished by the fewer secondary nerves, the ascendant inflorescences bearing flowers along a greater proportion of its length, shorter bracteoles and flowers and filaments with a 2-lobed appendage towards its base.

Type.

Panama. Darien: Rancho Frío to summit of Cerro Pirre, 07°51'N, 077°42'W - 07°58'N, 077°43'W (DMS), 500-1140 m, 30 Mar 1985, W. G. D'Arcy & G. McPherson 16210 (holotype: MO-4407602).

Description.

Robust herb to shrub 1.5-2.0 m. Leaf-bearing stems dark grey-brown, the internodes 15-43 × 4-6 mm; young stems regularly or sparsely pubescent, the hairs 0.25-0.75 mm, branched, dendritic, erect, crooked, not glandular. Axillary buds 1.5-2.5 mm, brown, densely pubescent, not subtended by a minor leaf. Lamina 135-285 × 32-124 mm, length width ratio 2.0-4.2, oblong-elliptic, obovate, elliptic, or oblong-obovate, chartaceous to subcoriaceous, brown or dull green, the upper surface glabrous, sparsely pubescent at the base, the hairs 0.375 mm, branched, erect, crooked dendritic, primary and secondary veins clearly visible to the naked eye, primary or primary and secondary raised; lower surface sparsely pubescent on nerves, the hairs 0.125-0.50 mm, branched, glandular, erect, crooked-dendritic, orange-brown; primary and secondary or primary to tertiary veins clearly visible to the naked eye, primary and secondary veins raised, the veinlets not visible, secondary veins 9-15 pairs, 30-45° to the midrib, straight, apically curved; base obtuse, cuneate, asymmetrical, obtuse-cuneate; margin entire; apex subcuspidate to cuspidate; petioles 12-23 × 1.75-3.0 mm, brown to very dark brown, moderatley pubescent when young, becoming glabrous with age or always glabrous, the hairs 0.25-0.75 mm. Inflorescences 1-3 per herbarium sheet, terminal, indeterminate, solitary, clustered towards the branch tips, 150-210 mm long, bearing 27-36 flowers borne in panicles of 10-16 clusters of flowers, each cluster bearing 1-3 flowers; peduncle ca. 30 × 2-3 mm, brown to very dark brown, sparsely pubescent, the hairs 0.375-0.675 mm, branched, dendritic, eglandular; bracts 7-41 × 1.5-12 mm, leaf-like; bracteoles 6-7 mm, narrow oblong to linear, sparsely pubescent; flowers subsessile or pedicellate, where pedicellate the pedicels 0.25-0.50 mm; flowers yellow-green or white, becoming purple blue; calyx 4-6 × 2.25-3.0 mm, the outer surface glabrous, the lobes 3 or 5, 0.75-1.75 mm, erect or spreading; corolla 26-30 mm long, the tube 23-27 mm long, 2-3 mm in diameter at the mouth, 1-2 mm at the base, glabrous, the lobes 5, 4.0-4.5 mm long; stamens 5, the filaments 22-23 mm long, equal, adnate for 16.5-17.5 mm, pubescent, with a bilobed appendage present at insertion point, the anthers 1.25 × 1.0 mm; style 22-25 mm, the stigma 0.50-0.75 × 0.675-1.0 mm. Infructescences ca. 125 mm long, bearing ca. 14 fruit; calyx 6 × 7.0-7.5 mm; fruit immature, 5-6 × 5 mm, purple-black when ripe. Seeds not seen.

Etymology.

This species is named in honour of Gill Stevens ( née Douglas, born 1965), botanist, colleague and close friend who died during the preparation of this manuscript. Gill, an algologist by training, helped pioneer the use of amateur groups in the collection of biodiversity data in the UK.

Distribution.

Cestrum gilliae is known from three cloud forest localities within the Cerro Pirre mountain range. Cerro Pirre covers an area of ca. 50 × 25 km. Using collection label data and Google Earth (accesssed June 6, 2011; images from 2003) the Extent of Occurrence is calculated to be ca. 260 km2.

Discussion.

Of the three collections of Cestrum gilliae seen, only one had been previously determined to species, as Cestrum langeanum D’Arcy. A comparison of the holotype and paratype material with type specimens from the herbaria listed in the Materials and methods section recovered Cestrum gilliae most similar to Cestrum morae Hunz. and to a lesser extent Cestrum langeanum D’Arcy (see Discussion for Cestrum darienense above). For this reason Cestrum gilliae is contrasted to both Cestrum morae and Cestrum langeanum on the basis of habit and inflorescence and flower morphology as summarised in Tables 7 & 8 respectively.

Conservation status.

Using IUCN criteria ( IUCN 2001) Cestrum gilliae is considered to be Near Threatened under IUCN (2001) criteria. The Extent of Occurrence is calculated to be ca. 260 km2 (Criteria B1, <5,000km2) and there are only three known localities (Criteria B1a, ≤5). No decline in geographic range or fragmentation of the habitat has been observed and Cerro Pirre is located within the Darién Biosphere Reserve, a UNESCO World Heritage Property. The Darién is, however, vulnerable to factors (see Conservation Status above for Cestrum darienense ) and any decline in geographic range or fragmentation would result in this species being assessed as Endangered. For this reason Cestrum gilliae is considered Near Threatened.

Paratypes.

PANAMA. Darién: Cerro Pirre ridge top near Rancho Plastico, 07°57'N, 077°42'W (DMS), 1200 m, 10-20 Jul 1977, J. P. Folsom 4253 (MO); Cuasí-Cana Trail between Cerro Campamiento and La Escalera to 'Paramo' east of Tres Bocas, 07°44'N, 077°44'W - 07°46'N, 077°47'W (DMS), 30 Apr 1968, J. H. Kirkbride & J. A. Duke 1277 (MO).

Figures

Figure 5. Cestrum gilliae A. K. Monro A Flowering stem B Style C Longitudinal section through the corolla showing stamen arrangement D Flower. Drawn from W. G. D'Arcy & G. McPherson 16210 (MO).