Conostegia oligocephala (Donn. Sm.) Kriebel, 2016

Kriebel, Ricardo, 2016, A Monograph of Conostegia (Melastomataceae, Miconieae), PhytoKeys 67, pp. 1-326 : 197

Conostegia oligocephala (Donn. Sm.) Kriebel comb. nov. Fig. 174

Conostegia oligocephala (Donn. Sm.) Kriebel. Basionym: Miconia oligocephala Donn. Sm., Bot. Gaz. 46: 111. 1908. Lectotype (designated here): Guatemala: Alta Verapaz: Cobán, alt. 1550 m (US), von Tuerckheim II-1781 (US!). Additional syntype: H. von Tuerckheim 8686 (US).

Description.

Shrubs to small trees 2-12 m tall with somewhat flattened cauline internodes that are densely covered with a whitish and ferrugineaous stellate indumentum; the nodal line not evident from the indument. Leaves of a pair equal to unequal in length.Petioles 0.5-3 cm. Leaf blade 3.5-14.2 × 1.5-5 cm, 5-plinerved, with the innermost pair of veins diverging in from the midvein 0.5-2 cm above the base in opposite or usually alternate fashion, elliptic, the base acute to obtuse, the apex acuminate, the margin denticulate to subentire, the adaxial surface glabrous, the abaxial surface densely covered with white stellate trichomes in between the veins and white intermixed with ferrugineus trichomes on the main veins. Inflorescence a terminal panicle 3.6-8 cm long, branching at or above the base, accessory branches absent, the axes covered with stellate hairs; bracteoles 2-5 × 0.5-3 mm, elliptic to linear-oblong, persistent. Flowers sessile or subsessile, 5 merous, not calyptrate or with the sepals fused in bud and rupturing, hypanthium 2.75-3.25 × 2.5-3 mm, campanulate, covered with stellate hairs, calyx tube 0.5 mm long, calyx lobes rounded-triangular to oblong, 1.5 × 1.5-2 mm, oblong, 1-1.5 mm long. Petals 3.5-4 × 3-4.5 mm, white, obovate, spreading, glabrous the apex rounded to emarginate. Stamens 10, 5-6 mm long, radially arranged around the style, the filaments 2.5-3 mm, with a geniculation near the apex, anthers 2.5-3 mm, linear-oblong, yellow, laterally compressed, the pore ca. 0.2 mm wide, ventrally inclined. Ovary 5-locular, half inferior, densely sericeous with trichomes surrounding and overtopping the stylar scar. Style ca. 5-7 mm long, straight but somewhat bent in some specimens, vertical distance from the anther to the stigma ca. 2.5-3 mm, the stigma punctiform, ca. 0.4-0.5 mm wide. Berry 4-5 × 4-5 mm, purple black. Seeds 0.65-0.8 mm long, angulate-ovoid, the testa smooth.

Distribution

(Fig. 175 ). Mexico and Guatemala at 1300-1950 m in elevation.

Conostegia oligocephala can be recognized by its leaf abaxial surface which is obscured by whitish and ferrugineaous trichomes, sessile flowers subtended by persistent bracteoles, non calyptrate calyx, and linear calyx teeth. This species has been confused with Conostegia plumosa and Conostegia xalapensis but can be distinguished from them by the lack of a calyptrate calyx and presence of evident calyx teeth. It is also similar to another non-calyptrate specie, Conostegia fulvostellata . See the latter species for differences between the two. The molecular phylogeny places Conostegia oligocephala as sister to Conostegia incurva with strong support. The two share a similar leaf indument and calyx teeth but are easy to separate based on inflorescence and flower size.

Specimens examined.

GUATEMALA. Alta Verapaz: Intersección de camino de terracería y Quebrada Sacsae, a lo largo del río, Kriebel et al. 5575 (NY, USCG).

MEXICO. Chiapas: steep wooded slope on the bank of the Río Hondo 4 miles north of Jitotol on the road to Pueblo Nuevo Solistahuacán, Breedlove 10134 (CAS); Lago de Monte Bello, 25 miles east of La Trinitaria, Breedlove 9712, 14981 (CAS); 10 km north of Jitotol near Río Hondo, Breedlove and Davidse 55149 (CAS); along Highway 195 between Ixtapa and Pichucalco 8 miles NW of Pueblo Nuevo Solistahuacán, Croat 47770 (CAS); at Clinica Yerba Buena, 2 km northwest of Pueblo Nuevo Solistahuacán, Raven and Breedlove 19919 (CAS); Colonia Kokijaz, Municipio Tila, Shilom Ton 6079 (CAS); on the slopes below Hy. 195 in the visinity of Clinica Yerba Buena, Thorne and Latrop 41087 (CAS).

Figures

Figure 174. Conostegia oligocephala. A Branch apex showing leaf abaxial surface and infructescence B Infructescence C Close up of an infructescence showing sessile flowers subtended by bracteoles D Close up of a fruiting hypanthium E Longitudinal section of a fruiting hypanthium showing setose rim around the style scar F Close up of the ovary with the most of the hypanthium removed. Photos of specimen vouchered R. Kriebel 5575.

Figure 175. Distribution of Conostegia oligocephala.