Dendrophthora apiculata Canelon , S.M. Nino , Dorr & Caraballo, 2020

Canelon, Daniela S., Nino, Santos M., Dorr, Laurence J. & Caraballo-Ortiz, Marcos A., 2020, Two new species of Dendrophthora (Viscaceae) from the Venezuelan Andes, PhytoKeys 140, pp. 1-10 : 1

1. Dendrophthora apiculata Canelon, S.M. Nino, Dorr & Caraballo sp. nov. Figures 2 , 3

Type.

Venezuela. Trujillo: Municipio Boconó, Parque Nacional Guaramacal, Páramo de Guaramacal, from summit of Boconó-Caserío de Guaramacal road to the television towers, 2900-3100 m, 13 June 2001, L.J. Dorr 8953, with B. Stergios & S.M. Niño (holotype: PORT!; isotypes: K, MO, US-00662868!).

Diagnosis.

Dendrophthora apiculata is distinguished from congeners by its rough striate stems; minute, ca. 0.5 mm long cataphylls surrounding all nodes; leaf blades 5-20 × 3-6 mm, apex apiculate with an apiculum 0.2-0.5 mm long; inflorescences usually 1(2) per leaf axil, staminate inflorescences triseriate and pistillate ones uniseriate; flowers ca. 1 mm long; and mature fruits globose-compressed, ca. 0.8-2 × 2-3 mm when dried.

Description.

Aerial parasitic shrubs, monoecious; yellowish-green when fresh and drying dark brown. Stems woody; erect branches 20-30+ cm long; mature nodes at 2-3 cm long intervals, dichotomous, with multiple branches; coarse, longitudinal striations along principal branches with some transversal striations in basal branches (striations not visible in distal branchlets), minute papillose trichomes dispersed or absent; some lenticels present; cataphylls at nodes ca. 0.5 mm long. Leaves opposite, coriaceous; petioles winged, 2-5 mm long, indistinct; blades obovate, 5-20 × 3-6 mm, base cuneate, apex apiculate with an apiculum 0.2-0.5 mm long, margin entire; veins reticulate with midvein evident on the adaxial side when fresh and inconspicuous when dried. Pistillate and staminate inflorescences separate, alternate on the same branch or branches either predominantly staminate or predominantly pistillate, usually 1 inflorescence per leaf axil, sometimes 2; fertile internodes usually 1(2), 7-18 mm long; staminate inflorescences triseriate; peduncles simple, 1-3 mm long, rugose; cup subtending inflorescence 1.5-1.8 × 2-2.5 mm, edge of cup papillose; basal portion of staminate inflorescences with 9-12 flowers per segment (see Fig. 2C ); flowers ca. 1 mm in diameter; embedded in an alveolus (sunken receptacle), emerging up to 2/3 during anthesis; pistillate inflorescences uniseriate; peduncles simple, 2-4 mm long, rugose; cup (sensu Kuijt) subtending inflorescence 0.8-1 × 1-2.5 mm, edge of cup papillose, with 3-5 flowers per segment, sometimes more (Fig. 3 ), flowers adjacent (sometimes touching each other); petals 3(4), triangular, glabrous. Fruits globose-compressed, ca. 0.8-2 × 2-3 mm when dried, ripening white-translucent, crowned by persistent petals.

Distribution and hosts.

Dendrophthora apiculata is known only from Guaramacal National Park (Trujillo state) between 2600-3100 m on both its northeastern and southwestern mountain slopes. This mistletoe grows in open areas of the páramo and evidently is uncommon throughout its distributional range. Its host range seems to be limited, as the only hosts recorded so far are the shrubs Cybianthus marginatus (Benth.) Pipoly ( Primulaceae ), Hypericum juniperinum Kunth ( Hypericaceae ), and Espeletia griffinii Ruiz-Teran & López-Fig. ( Asteraceae ). Interestingly, the mistletoes found so far on the first host listed were observed on lower and middle branches, while in the last one they were found at the tips of branches.

Phenology.

Reproductive individuals of Dendrophthora apiculata have been observed with flowers and fruits all year round, and the fruits seem to be an important source of food for the bird fauna present in the páramo and subpáramo habitats.

Etymology.

The specific epithet is derived from “apiculate,” which describes the minute sharp apiculum observed at the apex of leaves.

Discussion.

Dendrophthora apiculata is similar to D. lindeniana Tiegh., but the latter has stems up to 1 m long, dense papillose trichomes covering the entire plant, leaves with rounded apices with papillose edges, and the cup subtending the inflorescence is usually bifid. In contrast, D. apiculata has stems up to 40 cm long, coarsely striate stems with scarce papillose indumentum or papillae absent; leaves with a smooth margin and a persistent, minute apiculum 0.2-0.5 mm long at the apex; and a cup subtending the inflorescence that is usually whole (or rarely rounded).

Regarding their distributions, Dendrophthora apiculata is found in the Páramo de Vicuyal (ca. 2730 m) in Guaramacal National Park (Trujillo state), while D. lindeniana grows in the Páramo de Portachuelo (2860 m) ( Táchira state), near the border with Colombia. The known localities for these two species are separated one from the other by ca. 240 km.

Additional specimens examined.

Venezuela. Trujillo: Municipio Boconó, Páramo de Guaramacal, SE of Boconó, 09°10-14'N, 70°11-15'W, 2600-3100 m, 18 July 1990, L.J. Dorr, L.C. Barnett, W. Diaz, G. Aymard, F. Ortega & N. Murakami 7377 (NY, PORT); Carretera de tierra vía hacia las antenas, 09°14'29.0"N, 70°11'65.0"W, 2800 m, 23 Sep. 2000, M. Niño, A. Licata & L. Linárez 1385 (US); Sector El Campamento, UTM: 19 368148-1022056 [9.244052N, - 70.200324W], 2600 m, 13 Apr. 2019, S. Niño & D. Canelón 6112 (PORT, US); Páramo de Guaramacal, 3000-3100+ m, July 2002, B. Stergios & R. Caracas 19754 (PORT, US-00728477); Parque Nacional Guaramacal, Páramo Vicuyal, UTM: 1014040 N, 362685 E [9.171395N, - 70.249794W], 2730 m, 11 Apr. 2003, B. Stergios, L.J. Dorr, S.M. Niño & R. Caracas 20126 (PORT, US-00728399).

Figures

Figure 2. Dendrophthora apiculata. A Habit B fruit C basal flowers (staminate) (Photograph: D. Canelon).

Figure 3. Dendrophthora apiculata. A Terminal branches showing inflorescences and leaves, including an enlargement of a leaf apex showing the apiculum (striations are not visible in these terminal branches) B Cataphylls at the base of a node C Papillose indumentum D-F Segments of pistillate inflorescences G-I Pistillate flowers J, K Mature fruits. (Source: Stergios et al. 20126, US).