Clusia osaensis Hammel 2024, sp. nov.
Creators: name: Luján, Manuel
name: Wodcke, Emma
name: Hammel, Barry
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Malpighiales
Clusiaceae
Clusia
Clusia osaensis

description: Clusia osaensis Hammel sp. nov.
Type: Costa Rica. Puntarenas: Parque Nacional Corcovado, Pavo trail between Estación Sirena and Río Pavo, 8°30'00"N, 83°35'30"W, 5 m, 31 Dec. 1998, fl. ♀, C. Kernan, P. Phillips & P. Kernan 851 (holotype CR [INBI-OCRI001559875, 64630]; isotype MO).
http://www.ipni.org//urn:lsid:ipni.org:names:77348200-1
Shrub or tree, 2 – 7 m, epiphytic or less commonly terrestrial, dioecious; young branches drying light reddish-brown to reddish-brown, cylindrical, the epidermis not exfoliating; colourless resin. Leaves with petioles 1 – 3.5 cm, cylindrical or flattened distally on the adaxial surface and with a small proximal adaxial pit; laminas drying olive green or reddish-brown, 8 – 16× 4 – 9.5 cm, obovate to oblanceolate, bases attenuate or (rarely) acute, apices broadly rounded, coriaceous, midvein nearly complete sometimes bifurcating distally, 15 – 20 secondary veins at 50° – 55° to the midvein, 3 – 8 mm apart, obvious, joining into a submarginal nerve (1 – 3 mm from margin); resin lines, when visible (only on abaxial side and under magnification), intermittent lines often branched and curved which sometimes seem to form a mesh. Inflorescences deflexed to pendulous, 5 – 15× 5 – 13 cm, lax, 1 – 33 flowers; peduncles 1.5 – 6 cm; bracteoles 2 – 12, distal 2 just below flowers. Flower buds 6 – 7 (– 10) mm. Flowers unisexual, the perianth differentiated; sepals 4; petals 4 erect, cream or pale orange, fleshy, remaining almost closed during anthesis; androecium (staminate fls) without resin, uniform, c. 2.5 mm, convex, the androphore 0.5 – 1 mm, square; stamens c. 45, filaments free, 0.1 – 0.4 mm; anthers 1 – 1.5 mm, with lateral dehiscence; staminodes (pistillate fls) 16, grouped in 4 groups of 4, conspicuous, 3.5 – 4.5 mm, resembling stamens, non-resiniferous; apical stigmas 4, discoid, sessile. Fruits green to greenish-white or pink, 3.5 – 7× 2.5 – 3.5 cm, ellipsoid, without ribs, without prominent stylar residues, seeds ellipsoid, covered with an orange aril (Fig. 2).
RECOGNITION. Clusia osaensis is distinct from morphologically similar species for its relatively larger, obovate to oblanceolate leaf laminas and longer, deflexed-pendu-lous inflorescences. The pistillate inflorescences can be remarkably long and usually have a single flower with up to six pairs of bracteoles, separated from each other, dispersed along the rachis. Pistillate flowers stand out by having 16 staminodes. It is most like C. torresii with eight staminodes, and C. dotana with 24 – 26 (– 42) staminodes, both with similar leaves and fruits but smaller inflorescences and ovoid-globose seeds with a yellow aril (vs ellipsoid seeds with an orange aril in C. osaensis).
DISTRIBUTION AND HABITAT. Clusia osaensis occurs in wet forests from near sea level up to 1000 m, on the Pacific slope of Cordillera de Talamanca, N Fila Costeña (Fila Tinamastes), Valle de Coto Brus and Golfo Dulce (Map 1).
SPECIMENS EXAMINED. COSTA RICA. Puntarenas: Osa, Palmar, Cordillera Costeña Norte. Fila Retinto, aprox. 2.7 km NNE en línea recta desde Palmar Norte. Sendero que baja a través de remanente de bosque sobre ladera muy empinada, que sale de la torre del ICE y baja aparentemente hasta Palmar Norte, finca del Sr. Olivier Pérez y socios, 8°59'14.4"N, 83°27'8.8"W, 905 m, 25 March 2015, S. Lobo, A. Ruiz-Boyer, J. Solano & G. Alvarado 3575 (CR); Coto Brus, Parque Nacional (P. N.) La Amistad, Cordillera de Talamanca, Pittier, Aguas Calientes, aguas termales, rivera del Río Cotón. 09°01'30"N, 82°57'40"W, 1680 m, 1 Feb. 1995, E. Alfaro 38 (CR, MO); Coto Brus, Cuenca Térraba-Sierpe, entre Paso Real y San Vito, c. 2 km E de Unión, por Alto del Aguacate, 8°50'45"N, 83°01'40"W, 950 m, 26 May 2003, B. Hammel & I. Pérez 22791, 22792 (CR); Coto Brus, Cordillera de Talamanca, río Cotón, aguas termales cerca de Agua Caliente, 8°56'50"N, 82°55'35"W, 1000 m, 5 Sept. 1995, M. Moraga 291 (CR); Coto Brus, Cordillera de Talamanca, Refugio Nacional de Vida Silvestre (R. N. V. S.) Golfito, camino a las Torres, 1.5 km al E, 8°39'25"N, 83°09'25"W, 300 – 400 m, 1 Feb. 1992, U. Chavarría, B. Hammel, M. Grayum & J. Marín 534 (CR, MO); Golfito, 8°41'N 83°13'W, 30 m, 13 June 1997, W. Huber 14 (CR, WU); Golfito, sección Bosque de Los Austriacos, La Gamba, 8°41'N, 83°13'W, 70 – 300 m, 29 Dec. 1993, W. Huber & A. Weissenhofer 83 (CR, WU); Golfito, aprox. 3 km W del aeropuerto, 8°38'N 83°11'W, 10 m, 10 Jan. 1988, J. Gómez-Laurito 11667 (CR, MO); P. N. Piedras Blancas, sendero La Trocha, near La Gamba, 8°41"N, 83°13"W, 4 April 2002, E. G. Arauz Suarez 3246 (CR, WU); P. N. Piedras Blancas, sendero Fila and Catarata, near the Tropenstation La Gamba, 8°41"N, 83º13"W, 10 May 2002, E. G. Arauz Suarez 3474 (CR, WU); Reserva Forestal Golfo Dulce, Osa Peninsula, trocha de La Tarde Rd, 10 km SW of La Palma, S of Rincón de Osa, primary forest along red clay soil ridge, E of río Rincón valley, 8°37'N 83°28'W, 150 – 200 m, 28 April 1988, B. Hammel & R. Robles 16773 (CR, MO); Reserva Forestal Golfo Dulce, Cantón de Osa, quebrada Agua Buena, Estación Agua Buena de Boscosa: cerca campo de aterrizaje, c. 5 km W de Rincón, 8°42'00"N, 83°31'00"W, 50 m, 5 June 1992, B. Hammel, G. Galeano & A. Henderson 18510 (CR, MO); Rincón de Osa, region SW of airstrip, 20 – 60 m, 20 July 1974, J. & K. Utley 1070 (CR, F); San Vito de Coto Brus, c. 15 km N of town on road to ferry, 8°53'N, 83°5'W, 1000 m, 28 May 1986, B. Hammel, M. Grayum & G. de Nevers 15233 (CR, MO). San José: Tarrazú, Cuenca del Naranjo y Paquita, Cerros de Tarrazú, Cerros Diamante, entre el Cerro Hormiguero y el cruce a Naranjillo, 9°31'48"N, 84°02'39"W, 600 – 800 m, 7 March 1997, J. F. Morales & Abarca 6077 (CR, MO); Pérez Zeledón, fila Tinamaste, Bosque Eterno de Los Niños, 9°17'40"N, 83°46'00"W, 1000 m, 28 May 1998, O. Valverde 985 (CR, MEXU).
CONSERVATION STATUS. Clusia osaensis is known from six localities (sensu IUCN 2019) in Costa Rica, two of which are within protected areas, namely Golfo Dulce Forest Reserve, Golfito Mixed Wildlife Refuge, Piedras Blancas and La Amistad National Parks. The other localities are outside protected areas and represented by single collections. With an AOO of 48 km 2, an EOO of 5,130 km 2, a small number of localities and estimated decline in quality of habitat in most localities, we provisionally assess the conservation status for C. osaensis as Vulnerable [VU B1ab(iii)] based on the IUCN (2019) guidelines and criteria.
NOTES. Besides being distinct from Clusia dotana and C. torresii as indicated above, this new species is easily distinguished from the other two species with mesh-like resin lines of the Flava group. From C. dukei by its rounded leaf apex [Fig. 2] (vs acute to acuminate in C. dukei) and 16 staminodes (vs 8 in C. dukei) and from the more northern C. suborbicularis by having only 2 bracteoles closely subtending each flower (vs 6 – 22 in C. suborbicularis) and 16 staminodes (vs 8). As mentioned under C. dotana, this new species is potentially sympatric with the latter on the Pacific slopes of the Talamancan mountains, but usually grows at a lower elevation. It is allopatric with C. dukei, C. suborbicularis and C. torresii. Clusia osaensis is treated as “ Clusia sp. H ” in the Manual de Plantas de Costa Rica (Hammel 2010), where a key for species identification is provided.
description: Published as part of Luján, Manuel, Wodcke, Emma & Hammel, Barry, 2024, Two new species of Clusia (Clusiaceae) endemic to Costa Rica, pp. 881-887 in Kew Bulletin 79 (4) on pages 885-886, DOI: 10.1007/s12225-024-10225-0, http://zenodo.org/record/15119743