Graffenrieda jefensis Almeda, Alvear & Humberto Mend., 2014

Graffenrieda jefensis Almeda, Alvear & Humberto Mend. View in CoL sp. nov. ( Fig. 1 View FIGURE 1 )

Graffenrieda jefensis is distinguished by its consistently 5-merous flowers, linear-oblong anther thecae with notched or emarginate apices, leaf bases with two revolute lobes on each side of the blade, costate hypanthia, calyptrate calyx, 3- locular ovary and persistent erect calyx teeth. Closely related species with a calyptrate calyx, 5-merous flowers, and 3- locular ovaries differ in having acuminate or caudate-acuminate leaf apices, anther thecae that are subulate, petals that are basally attenuate or clawed, and calyx teeth that are reduced to small inconspicuous tubercles.

Type:― PANAMA. Panama province: Cerro Jefe, 1000 m, 11 June 1975 (mature buds), S. Mori 6524 (holotype: CAS! ; isotypes: MEXU , MO! , PMA ).

Tree 8−9 m tall. Young branches, petioles, and inflorescence branches densely to moderately rufescent, lepidote becoming glabrescent. Internodes 1−6.5 cm long, the uppermost quadrangular to subquadrangular and irregularly sulcate when dry but becoming terete with somewhat enlarged nodes with age. Petioles canaliculate, 2−4 cm long. Leaves opposite and isophyllous, 7.5−14 × 4.5−7.5 cm, elliptic, apex blunt-cuspidate, base obtuse, slightly decurrent, with two triangular revolute lobes or flaps ca. 1.5–3 mm long on each side of the blade ca. 1.5−3 mm above the petiole/laminar junction, both surfaces densely lepidote on young leaves but the adaxial surface typically glabrescent with age. Venation acrodromous, the primary nerve somewhat elevated on the adaxial surface, very prominent on the abaxial surface, with two pairs of secondary nerves but only the innermost pair extending to the blade apex and converging with the primary nerve. The secondaries basal to shortly supra-basal, diverging from the primary nerve up to 2 mm from the base, secondary nerves impressed on the adaxial and prominent on the abaxial surface, tertiaries (transversals) impressed on the adaxial surface, flat to slightly prominent on the abaxial surface. Inflorescence a terminal, open and multiflorous panicle, 5−14.5 cm long (including the peduncle, which is 2.5−5.5 cm long), with up to 4 nodes, typically with 4 branches on the proximal node and 2 branches on the upper nodes; paracladia 4.5−6 cm long, with 2−3 levels of branching; ultimate units of each paraclade with clusters of 3−11 flowers. Bracts 2 × 0.8 cm, similar to the leaves in shape and vestiture. Bracteoles apparently early caducous and not seen. Flowers 5-merous, on pedicels 0.5−1 mm, lengthening to 2−3 mm on fruiting hypanthia. Hypanthium 2− 2.5 × 2 mm, suburceolate, externally costate and moderately to densely rufescent lepidote (the scales 0.1 mm in diameter). Calyx fused into a hyaline attenuate-apiculate conic calyptra 2.8−3.2 mm long while in bud, sparsely lepidote, dehiscing and falling away as a unit at anthesis; the 5 external deltoid teeth callose-thickened, erect, 1−1.5 mm long (from torus to apex on flowers) and persistent on mature hypanthia, calyx tube less than 0.2 mm long. Petals 2.5−3 × 1.5 mm, ovate-lanceolate, apex acute, base rounded-truncate, white, entire and glabrous. Stamens 10, isomorphic; filaments 0.5−0.8 mm long, pale yellow, ligulate; anther thecae 1.8−2.3 × 0.5 mm, yellow, linearoblong, notched or emarginate apically, the solitary apical pore 0.2 mm wide and somewhat ventrally inclined; connective not prolonged but modified into a deflexed dorso-basal acute, glabrous spur (appendage) 0.2−0.3 mm long. Ovary 1−1.5 × 0.75 mm, ovoid, the apex moderately lepidote with a lobulate collar 0.2−0.3 mm long, (2) 3- locular, basally 1/2−1/3 inferior; style 2.8−3.3 mm long, linear, glabrous; stigma punctiform. Capsules 3 × 3 mm; the enveloping hypanthium 3.5 × 3 mm, conspicuously costate externally and moderately to densely rufescent lepidote (the scales 0.1 mm diameter). Seeds 1−1.3 × 0.2−0.3 mm, cuneiform to narrowly pyramidate, brown, lateral symmetrical plane oblong-arcuate, the chalazal end typically flattened vertically and sometimes tapered to an acute projection on the raphal side that is confluent with the raphal ridge, antiraphal symmetrical plane angulate or rounded, the raphal zone narrow, oblong, and mostly forming a thin carinate ridge extending the entire length of the seed, testa ± granulate and inconspicuously papillate especially on the antiraphal side.

Distribution and habitat:― Endemic to the upper slopes of Cerro Jefe east of the Canal Area in Panama where it grows in wet cloud forests with species of Clusia ( Linnaeus 1753: 509) and Colpothrinax cookii ( Read 1969: 13) at 850−1000 m. Cerro Jefe was an important island refugium from the middle of the Miocene until the land bridge between North America and South America was established ca. 3.5−2.4 million years ago ( Graham 1985, Carrasquilla 1997, Almeda 2000a). The high incidence of vascular plant endemism on Cerro Jefe and adjacent Cerro Azul is a reflection of this geologic history ( Lewis 1971). Of the 1230 + species of plants thought to be endemic to Panama ( Carrasquilla 1997), over 150 are restricted to the Cerro Jefe region, including the following six locally endemic species of Melastomataceae : Adelobotrys jefensis ( Almeda 1981: 210) , Blakea hexandra ( Almeda 1990: 320) Penneys & Almeda in Penneys & Judd (2013: 26), Miconia jefensis ( Almeda 2000b: 43) , Miconia morii ( Almeda 2000b: 46) , Miconia peltata ( Almeda 1989a: 218) , and Tessmannianthus carinatus ( Almeda 1989b: 2) .

Phenology: ―This species has been collected with mature flower buds in early June, and in fruit in early and late July.

Conservation status:― This species is known only from the summit forest of Cerro Jefe which has protected status since it is within Chagres National Park (1290 km ²). This park was created in 1984 to protect all lands that contribute to water production and sustainability of the Chagres watershed which in turn protects the Panama Canal and Lake Alajuela ( Carrasquilla 1997). Based on IUCN guidelines and criteria ( IUCN 2001, 2011) and our current knowledge of its limited distribution, this species is assigned a provisional IUCN conservation status of Endangered (EN).

Etymology: ―The specific epithet is derived from Cerro Jefe, the type and only known locality for this species.

Additional specimens examined (paratypes):― PANAMA. Panama province: Cerro Jefe, NE of Panama City , 850−900 m, c. 9°15’ N, 79°30’ W, 12 July 1986 (fr), G. McPherson 9736 ( CAS!, MO, PMA, US) GoogleMaps ; vicinity of Cerro Jefe , 850 m, c. 9°15’ N, 79°30’ W, 24 July 1986 (fr), G. McPherson 9797 ( CAS!, CR, MO, PMA) GoogleMaps .

Discussion: — Graffenrieda jefensis is distinguished by its 5-merous, pedicellate flowers, oblong anther thecae with notched apices, leaf bases that are slightly decurrent with two triangular revolute lobes on each side of the blade, externally costate hypanthia, calyptrate calyx that falls away as a unit following anthesis, (2) 3-locular ovary, and external deltoid calyx teeth that are callose thickened, erect, and persistent on fruiting hypanthia. The calyx teeth are so prominent that they superficially resemble true calyx lobes.

In the key to species of Graffenrieda with a calyptrate calyx ( Goldenberg & Meirelles 2011), G. jefensis keys to the couplet that includes G. bella ( Almeda 1984: 275) and G. micrantha ( Gleason 1950: 346) L. O. Williams (1963: 564) . These three Panamanian species share a calyptrate calyx, 5-merous flowers, and a 3-locular ovary but they are otherwise distinct and readily separated from one another. In G. bella , which also has leaf bases with revolute lobes on each side of the blade abaxially, the leaves are smaller (4.7−8 × 2.1−4 cm) with an acuminate apex, the hypanthium (at anthesis) is narrowly subcylindric, the calyx teeth are poorly developed and evident as blunt tuberculiform projections 0.25−0.5 mm long, the petals are cuneate to distinctly clawed at the base, the anther thecae are distinctly subulate, and the ovary is copiously lepidote distally. Graffenrieda bella is also allopatric with a distribution restricted to Chiriquí and Veraguas provinces west of the Canal Area . Graffenrieda micrantha , which is only known from the type (Fish Creek mountains in Bocas del Toro province in western Panama), differs by its terete uppermost branches. It also has large leaf blades (8−20.5 × 4.5−9 cm) like G. jefensis but the apices are caudate-acuminate and the base is not decurrent and has divergent auriculate lobes at the petiole/laminar junction, small hypanthia at anthesis (ca. 1.25 mm long to the torus), inconspicuous calyx teeth (0.25 mm long) evident as mere tubercles, small narrowly oblong-lanceolate petals (3 × 0.5 mm), and minute anther thecae (2−2.25 mm).

The floral measurements given in the above description for G. jefensis were taken from mature hydrated buds so dimensions may increase somewhat when specimens are collected with fully open flowers.