Blakea ricardoi Michelang. & D.Santam., 2020

Michelangeli, Fabián A. & Santamaría-Aguilar, Daniel, 2020, A new species of Blakea (Melastomataceae: Blakeeae) with pendulous flowers from Costa Rica, Phytotaxa 442 (1), pp. 11-19 : 12-17

Blakea ricardoi Michelang. & D.Santam. sp. nov. ( Figs. 1 , 2C–F , 3C–E ).

Diagnosis:—A terrestrial shrub with pendant flowers and green petals that differs from B. gregii by the longer peduncles (5–6.5 cm vs 2–3 cm), and leaf indumentum of roughened trichomes 0.3–0.45 mm long (vs. smooth trichomes 0.8–1.7 mm long).

Type: — COSTA RICA. Limón: Valle de la Estrella, Fila Matama, Cerca de 11 km SW del pueblo de Aguas Zarcas. Punto 10 C. 09°47’49”N 083°09’44”W, 1400–1500 m elev., 29 October 2007 (fl., fr.), Daniel Santamaria 6703 with D. Solano, M. Moraga, C. Godínez, A. Rodríguez (holotype MO-6646078 [barcode: 2855274]!; isotypes: CR [barcode: ex-INB 4125202]!, PMA-76446 [barcode: 77250]!, NY [barcode: 02146181; barcode: 02684958; barcode: 02685025]!) .

Terrestrial shrub. Distal branchlets quadrate, becoming rounded with age, the younger nodes swollen up to 8.5 mm wide, with internodes 6–18 mm long, 4–6 mm wide, densely pubescent, the trichomes roughened, 0.5–1 (–1.2) mm long, later glabrate. Mature leaves isomorphic or nearly so; petioles 1.4–2 cm long, densely pubescent, the trichomes simple and moderately roughened, 0.4–1.1 mm long; blades 4.5–11.8 × 2.6–5.9 cm, subcoriaceous when dry, elliptic-ovate to obovate, apex rounded to very shortly acute or mucronate, base narrowly obtuse to rounded, margin markedly revolute (both live and when dry), the venation with one pair of secondary veins symmetrically diverging 4–7 mm above the base and running 4.5–7 mm from the margin, tertiary veins percurrent, spaced 3–5 mm apart at the widest portion of the blade, all veins elevated on the abaxial surface, impressed to slightly impressed on the adaxial surface; young leaves densely pubescent on both surfaces, the trichomes roughened, 0.3–0.45 mm long, the surface quickly becoming very sparsely pubescent on the abaxial surface but persistent on the primary and secondary veins, and glabrous on the adaxial surface; domatia on adaxial leaf surfaces absent. Flowers pendant, solitary or in fascicles of up to 5 in the axils of the distal branches; peduncles 5.1–6.5 cm long, densely pubescent, the trichomes roughened, 0.35–0.5 mm long. Floral bracts thickened, sessile, entire; outer bracts 5.8–7.6 × 5–5.2 mm at anthesis (larger in young fruits), basally connate for 2–3.2 mm, elliptic to elliptic-ovate, apex round, margin sparsely ciliate, abaxial surface densely covered by roughened trichomes up to 0.5 mm long, denser towards the middle, with only a midvein visible, this slightly elevated but obscured by the trichomes, the adaxial surface glabrous; inner bracts 5.8–6.2 × 5.4–5.6 mm, free to the base, rotund to broadly ovate, the apex round, the margin sparsely ciliate, the adaxial surface with roughened trichomes as on the peduncles and outer bracts, these denser towards the apex and areas exposed in between the outer bracts, the midvein obscured by the trichomes. Hypanthium at anthesis campanulate to suburceolate, 7.5–8.8 mm long to the torus, 7.2–7.3 mm diameter distally at the torus, glabrous to very sparsely pubescent, the trichomes stellate (the botton ¾ of the surface concealed by the inner bracts). Calyx tube 2.5–3.1 mm long, light green at the base, reddish towards the apex; calyx lobes erect, 1.1–1.3 mm long and 4.2–4.5 mm wide at the base, red, broadly ovate to deltoid-ovate with a blunt callose-thickened tooth on the abaxial apex of each lobe, roughened along interlobe sinuses, these tearing irregularly later in anthesis, adaxially sparsely pubescent, especially towards the apex, the trichomes sessile-stellate or shortly pedicellate-stellate, <0.3 mm diameter, abaxially sparsely pubescent, the trichomes as on the abaxial surface and mostly restricted to near the apex. Petals 6, glabrous, connivent to imbricate when fully expanded, green, obovate, apically rounded to emarginate, otherwise margins entire but irregularly glandular-ciliate, mostly on the exposed margin, forming a tube, 8.5–10 × 7–8.2 mm. Stamens 12, isomorphic, free and encircling the exserted style; filaments complanate, glabrous, 4.5–5.1 mm long, 1.1 mm wide; anthers 3.4–4.1 mm long, 1.6 mm wide, purple, elliptic-oblong, laterally compressed, each anther tipped with two dorsally- to upright-inclined pores; connective dilated dorso-basally ca. 0.5 mm above the filament insertion into a blunt spur. Ovary inferior, 6-celled, the apex glabrous and 12-lobulate, lacking a cone or collar around the style insertion. Style straight, glabrous, 10–13 mm long, conspicuously exserted beyond the petals at anthesis, stigma truncate. Mature berries and seeds not seen.

Phenology:— Collected in flower and fruit in October.

Habitat and distribution:— Blakea ricardoi is only known from the type collection on the Caribbean slope of the Talamanca Cordillera in the Parque Internacional La Amistad. Only one individual was seen, growing 1400 and 1500 m elev., in a relatively open grassland, among some ferns [probably Sticherus Presl (1836: 51) and Pteris Linnaeus (1753a: 1073) ], as well as with trees and shrubs of Clethra Linnaeus (1753b: 396) ( Clethraceae ), Drimys granadensis Linnaeus (1781: 269) ( Winteraceae ), Miconia Ruiz & Pavon (1794: 60) ( Melastomataceae ) and Oreopanax Decaisne & Planchon (1854: 108) ( Araliaceae ). Only a few yards from this individual, the field team also collected the types of Ternstroemia amistadensis Q. Jiménez & D. Santam. in Santamaría-Aguilar et al. (2015: 88), and Burmeistera flava Rodríguez & Solano Peralta (2018: 7) . This area is also the habitat of Byrsonima herrerae Anderson (1995: 22) and Zamia gomeziana Acuña C. (2010: 29) , unusual elements of the Costa Rican flora.

Conservation status:— Blakea ricardoi is known only from the type collection. Although this locality is inside a national park, the area is poorly collected. Based on the lack of information and the paucity of material we recommend that the species be considered Data Deficient ( DD) under the IUCN guidelines ( IUCN 2012; IUCN Standards and Petitions Subcommittee 2017).

Etymology:—It is a pleasure to honor our friend Ricardo Kriebel (1979–) with this species; Ricardo is a Costa Rican botanist who that has contributed greatly to our knowledge of the Mesoamerican Flora, particularly in the Dichapetalaceae , Gesneriaceae , Lamiaceae , Melastomataceae and Symplocaceae . Also, the second author is very grateful to him for personal support and motivation, and the first author for meaningful discussion in the field and laboratory.

Discussion:—Inflorescence and floral morphology undoubtedly places Blakea ricardoi in the B. purpusii group, characterized by pendant flowers that produce nectar and have green petals that form a tube at anthesis. Among these species, the lack of saccate appendages at the base of the leaf blade on the abaxial surface, calyx morphology, petal suggest a close affinity to B. gregii . Indeed, when keying out B. ricardoi in any of the keys that contain these species ( Almeda 1990, 2000; Almeda 2009) it comes out with B. gregii and B. purpusii , but it does not match either one. Blakea ricardoi differs from B. gregii by the longer peduncles and the rest of the characters mentioned in the diagnosis. Additionally, the calyx lobes are shorter in B. ricardoi (1.1–1.3 vs. 2–4 mm long). It also differs from B. purpusii by the longer peduncles, smaller floral bracts and the presence of roughened trichomes (see key below).

Of the five previously described species in this group, three ( B. austin-smithii , B. chlorantha , B. penduliflora ) were included in the phylogenetic analysis by Penneys and Judd (2013a), and unsurprisingly, they all form a clade, sister to B. fuchsiodes Almeda (1989: 137) , another species with pendant flowers, but with conspicuously longer red bracts and magenta to pink petals. Penneys and Judd (2013a) named this group the “vertebrate pollination clade”. Blakea austin-smithii , B. chlorantha and B. penduliflora had been suggested to be rodent-pollinated ( Lumer 1980; Lumer & Schoer 1986; Lumer 2000), while B. purpusii has been reported as bird-pollinated ( Lumer 2011). The notion of rodent pollination in Blakea has been challenged based on observations of hummingbirds visiting the same species reported as rodent pollinated, and the absence of floral scents ( Langtimm & Unnasch 2000; Wester et al. 2016). However, dual vertebrate pollination syndromes in other Melastomataceae have been found ( Dellinger et al. 2019a; Dellinger et al. 2019b), and the floral morphology of the Blakea purpusii group resembles that found in some species of Meriania Swartz (1798: 823) with mixed vertebrate pollination syndromes. As already pointed out by Wester et al. (2016), this shows the need for further pollination studies in these species of Blakea involving both diurnal and nocturnal observations on the same individuals, and that assessment of effective pollen transfer by the different visitors.

The type material of Blakea ricardoi , was wrongly identified as B. penduliflora by the second author. Duplicates were distributed under this name, which was reported by Monro et al. (2017).

Figures

FIGURE 1. Blakea ricardoi. A. Flowering branch with detail of the leaf apex. B. Peduncle and immature fruit. C. Inner (left) and outer (right) bracts. D. Flower before anthesis. E. Petal. F. Flower bud, with petals removed and calyx in longitudinal section. G. Immature fruit in longitudinal sections. H. Anther from flower bud in dorsal (left) and lateral (right) view. (Drawn by Bobbi Angell from Santamaria et al. 6703, NY and MO).

FIGURE 2. Scanning electron photographs of the indumentum of Blakea gregii and B. ricardoi. A–B. Blakea gregii. A. Adaxial surface of young leaf. B. Abaxial surface of young leaf. C–F. Blakea ricardoi. C. Adaxial surface of young leaf. D. Abaxial surface of young leaf. E. Detail of peduncle trichomes. F.Abaxial surface of outer floral bract. (A–B from Almeda 6137, NY; C–F from Santamaria et al. 6703, MO, NY).

FIGURE 3. Field photographs of Blakea gregii and Blakea ricardoi. A–B. Blakea gregii. A. Flowering branch with flowers and young fruits. B. Flower at anthesis. C–E. Blakea ricardoi. C. Leaf abaxial surface. D. Flowers in bud and at anthesis. E. Branch with young fruits. (A–B photographs by Petra Wester; C–D photographs by Daniel Solano).