Conostegia fraterna (Gleason) Kriebel, 2016

Kriebel, Ricardo, 2016, A Monograph of Conostegia (Melastomataceae, Miconieae), PhytoKeys 67, pp. 1-326 : 172-174

Conostegia fraterna (Gleason) Kriebel comb. nov. Fig. 156

Conostegia fraterna (Gleason) Kriebel. Basionym: Clidemia fraterna Gleason, Brittonia 2(4): 323. 1937. Type: Costa Rica. San José: collected near El General, July 1936, A. Skutch 2687 (holotype: NY!, isotype: GH!, K!, MICH!, S!, US!).

Description.

Shrub 1-3 m tall with terete branches densely covered with a stellulate lepidote indument; the nodal line not evident. Leaves at each pair equal to unequal in size. Petiole 0.5-1.5 cm. Leaf blade 5-17 × 2.9-6.7 cm, 5-plinerved, with the innermost pair of veins diverging from the midvein 1-5 cm above the base in alternate or opposite fashion, elliptic, the margin entire, the base decurrent on the petiole, the apex acuminate, adaxially glabrous, abaxially deciduously stellulate lepidote but appearing glabrous. Inflorescence an openly branched pseudolateral cyme 2.5-5 cm long borne on both leafy and defoliated nodes, branching at or above the base into pedunculate mostly 3-flowered glomerules, accessory branches absent, rachis inconspicuously stellulate lepidote, paired bracteoles subtending each glomerule ovate, 2-3 × 2 mm, persistent and fused at the base, paired bracteoles subtending each flower elliptic-ovate, 2-2.5 × 1.5 mm, persistent. Flower buds 2.5-4 × 2.5-2.75 mm. Flowers 5-merous, sessile, calyx not calyptrate but fused in bud, rupturing at anthesis into 3-5 ovate hyaline lobes, 0.5-1 × 1 mm, external calyx teeth triangular-subulate, 0.25-0.5 mm long; the hypanthium broadly campanulate, 2-2.5 × 2-2.5 mm long, densely stellate tomentose. Petals 3.5-4.6 × 1.5-2.8 mm, white, oblong-obovate, rounded apically, reflexed at anthesis. Stamens 10, 2.5-3.5 mm long, radially arranged around the style, the filament 1.4-2 mm without an evident geniculation, translucent white, anthers 1.2-1.5 × 0.5-0.75 mm, elliptic-oblong, laterally compressed, yellow, the pore ca. 0.15 mm wide, dorsally inclined. Ovary 5-locular, totally inferior, apex flat and glabrous except for s few minute glands. Style ca. 5.7-5.9 mm long, straight to slightly bending, vertical distance from the anther to the stigma 1.9-2.15 mm, horizontal distance absent, stigma truncate, 0.25-0.37 mm wide. Berry 3.5 × 3.5 mm when dry, purple-black. Seeds ca. 0.5 mm long, pyramidal, the testa asperulate or undulate.

Distribution

(Fig. 157 ). On the foothills of the Pacific slope of Talamanca Cordillera in Valle del General and San Vito de Coto Brus and barely reaching neighboring Panama, 950-1300 m in elevation. One outlying population collected on the south side of Lake Arenal in northern Costa Rica.

Conostegia fraterna is a distinctive species that can be identified on the basis of its short petiolate, narrow, plinerved leaves, and unusual inflorescence which consists of pedunculate mostly 3-flowered glomerules. This kind of inflorescence is not seen in any other species of Conostegia . The sessile flowers with fused buds that rupture at anthesis, herkogamous flowers, and broad anthers are also helpful to place it in section Geniculatae . Conostegia fraterna did not fall as sister to any species with support in the recent molecular phylogeny. Nevertheless, it fell in a clade that includes similar looking species such as Conostegia cinnamomea , Conostegia dissitiflora and Conostegia grayumii . All these species are glabrous or just barely pubescent and plinerved like Conostegia fraterna . Gleason (1937) compared this species to Clidemia conglomerata and Clidemia involucrata . Of the latter two species, he believed Clidemia involucrata to be the closest relative to Conostegia fraterna . Clidemia involucrata differs in its glandular pubescence, ciliate-serrulate margins and 3-locular ovary. Based on the molecular phylogeny available ( Goldenberg et al. 2008), we know they are not closely related at all. A seed micrograph of this species is provided in Ocampo and Almeda (2013).

Specimens examined.

COSTA RICA. Guanacaste: Río Negro ford on south side of Lake Arenal, 10 km NNE of Santa Elena, Haber et al. 4808 (INB, MO) . Puntarenas: E. B. Las Cruces, Kriebel 5774 (INB) . PANAMA. Chiriquí: along road between Volcán and Río Sereno, 13.7 mi W of Volcán, Croat 66335 (CAS, MO); road from Volcán to Rio Sereno , 16.0 km from Rio Sereno , Folsom 4053 (CAS, MO) .

Figures

Figure 156. Conostegia fraterna. A Habit B Leaf adaxial surface C Inflorescence D Close up of flower E Close up of flower bud F Pickled flower G Longitudinal section of a flower at anthesis with all parts removed H Petal I Stamen J Style. Photos of specimen vouchered R. Kriebel 5774.

Figure 157. Distribution of Conostegia fraterna.