Passiflora tacanensis K. Porter-Utley. Brittonia 59(1): 25. figs 1 & 2. 2007.

Porter-Utley, Kristen, 2014, A revision of Passiflora L. subgenus Decaloba (DC.) Rchb. supersection Cieca (Medik.) J. M. MacDougal & Feuillet (Passifloraceae), PhytoKeys 43, pp. 1-224 : 106-109

14. Passiflora tacanensis K. Porter-Utley. Brittonia 59(1): 25. figs 1 & 2. 2007. Figs 46, 47

Type.

Mexico. Chiapas: Mpio. Unión Juárez, Volcán Tacaná, entre Talquián & Toniná, 1700-2700 m, 7 May 1987, E. M. Martínez S. 20782 (holotype: MEXU! [MEXU00665952]).

Description.

Vine, pubescent with unicellular curved trichomes on petiole, adaxial leaf surface, and stipules 0.28-0.38 mm long, 0.03 mm wide, also minutely antrorsely appressed-puberulent throughout with unicellular, curved trichomes, 0.06-0.08 mm long, 0.02 mm wide. Flowering stems 1.5-1.8 mm in diameter, terete or somewhat compressed. Stipules 6.3-7.5 mm long, 2.5-3.5 mm wide, ovate, acute to acuminate; petioles 2.3-2.6 cm long, commonly bearing at or just below the middle (0.44-0.50 of the distance from the base toward the apex of the petiole) 2, elliptic, opposite to subopposite, sessile, discoid nectaries with the rims slightly raised, 1.0-1.1 mm wide (on the widest axis), 0.5-0.6 mm high. Laminas 3.8-5.3 cm long, 12.4-14.2 cm wide, membranous, subpeltate or slightly peltate (the distance from leaf base to point of petiole insertion 1.0-1.7 mm), transversely elliptic, 3-lobed 0.02-0.10 of the distance to the leaf base at the deepest sinus, lateral lobes 6.9-7.5 cm long, 2.6-4.2 cm wide, elliptic, acute to attenuate, central lobe elliptic or present as an obtuse to rounded tip, central vein 3.7-5.2 cm long (measured from point of petiole insertion to the leaf apex), angle between the lateral lobes 109-130°, ratio of lateral lobe to central vein length 1.41-1.86, margins entire, hyaline, primary veins 3, diverging and branching above base, laminar nectaries absent; tendril 0.7-0.9 mm wide, present at flowering node. Pedicels 11.9-13.0 mm long in fruit, 0.5 mm wide, paired in the leaf axils; bract(s) absent. Flowers not seen. Stipe 6.9-8.5 mm long in fruit, 0.5-0.6 mm wide. Berry 25.0-26.0 mm long, 24.0-26.0 mm in diameter, ellipsoid to globose, very dark purple. Seeds ca. 20, 4.6-4.9 mm long, 2.9-3.1 mm wide, 2.0-2.1 mm thick, obovate in outline, acute at both ends, reticulate-foveate with each face marked with ca. 22-26 foveae.

Phenology. Flowering and fruiting May.

Distribution. Mexico, in the state of Chiapas. Bosque mesófilo de moñtana (montane moist forest), 1700-2700 m altitude.

Discussion. Passiflora tacanensis is known only from the general type locality and though Martínez ( Martínez 20782) states that the flowers are purple, the specimen does not possess flowers and I have not been able to locate any duplicates. It was found in montane mesophytic forests on Volcán Tacaná in southwestern Mexico and was collected in May during the rainy season.

Passiflora tacanensis is very similar to Passiflora eglandulosa , which grows on adjacent volcanic cones in San Marcos, Guatemala. The mature leaves of Passiflora tacanensis greatly resemble the juvenile leaves of Passiflora eglandulosa and are trilobed, with the middle lobe greatly reduced and widely obtuse to truncate. The laminae are also cordate and eglandular, and both of these species possess wide foliose stipules. However, Passiflora tacanensis possesses petiolar glands positioned near the middle of the petiole, whereas Passiflora eglandulosa does not possess petiolar glands. In addition, the fruits of Passiflora tacanensis possess more seeds and the chalazal and micropylar ends of the seed are inclined toward the raphe.

Specimens examined. MEXICO. Chiapas: Mpio. Tapachula, Volcán Tacaná. On trail between Talquián and the border of Guatemala, 1901 m, Porter-Utley et al. 436 (KESC); Mpio. Tapachula, Volcán Tacaná. On trail between Talquián and the border of Guatemala, 1857 m, Porter-Utley et al. 441 (KESC).