Bomarea pastazensis J.L.Clark, Fierro-Minda & N.Exe, 2023

Clark, John L., Fierro-Minda, Alisson, Exe, Nolan, Johnson, Mia, Tribble, Carrie M. & Jost, Lou, 2023, Bomarea pastazensis (Alstroemeriaceae), an exceptionally small new species from the eastern Andean slopes of Ecuador, PhytoKeys 235, pp. 31-42 : 31

Bomarea pastazensis J.L.Clark, Fierro-Minda & N.Exe sp. nov.

Figs 2 , 4

Diagnosis.

Similar to Bomarea pumila Griseb. ex Baker, differing in plant height reaching 10-14 cm (vs. 5-8 cm high in B. pumila ), pubescent stem (vs. glabrous stem in B. pumila ), the presence of ciliate leaf margin (vs. glabrous leaf margin in B. pumila ), and the presence of dark spots on the petals (vs. no spotting on the petals in B. pumila ).

Type.

Ecuador. Tungurahua: Cantón Baños, Parroquia Rio Verde , Cerro Candelaria Reserve ( Fundación EcoMinga), upper Pastaza watershed, 1°28'39.33"S, 78°17'53.61"W, 3642 m, 10 Mar 2016, J.L. Clark 14839 (holotype: QCA! [245371]; isotype: SEL! [079072]) .

Description.

Terrestrial or epiphytic herb. Rhizome short with multiple underground fusiform to globose root tubers, pale and heavily stippled with dull reddish-purple spots, 5-9 × 3-4 mm, surface striate, yellowish-brown with red spots (Fig. 2H ). Stem erect, 10-14 cm long, ca. 0.13 cm in diameter, slender, terete, base pubescent, apex puberulous, internodes 0.6 cm long. Leaves alternate; blade ovate, 1.4-1.8 × 0.4-0.7 cm, base rounded to obtuse, apex acute, abaxially glabrous, adaxially light green, suffused with whitish-translucent trichomes, ca., 0.2 mm long, clustered along veins; blades with 5-7 prominent parallel veins, raised below and slightly raised above; margin hyaline, slightly revolute with unicellular trichomes to 0.2 mm long; petioles resupinate and canaliculate, 0.1-0.4 cm long, basal leaves reduced to scales. Flowers produced from the stem apex, usually one (rarely two) apical flower(s) per stem.; pedicels 1-1.4 cm long, terete, with brownish red to dark purple trichomes, bisexual, actinomorphic, epigynous. Sepals 3, 1.0-1.3 × 1.0-1.2 cm, each sepal with 6 parallel veins, broadly ovate, apically rounded, bright red to orange-red with a 1 mm green to black claw, inner and outer surfaces glabrous. Petals 3, basally constricted and caniculate, distally obovate to broadly spathulate, 1.5-1.6 × 0.6-0.7 cm, greenish yellow, puberulous at base, inner surface with 3 large reddish-brown spots, outer surface uniformly yellow (occasionally yellow suffused with red from the inner spots). Androecium of 6 free stamens, 0.8-0.9 cm long, thickened near center of filaments; anthers pseudo-basifixed, 0.3 × 0.1 cm, fusiform; pollen grains lilac. Gynoecium comprised of three fused carpels, ovary 0.5 × 0.4 cm with surface covered with glutinous trichomes, style ca. 1 cm long, stigma with three circinate lobes. Fruits not observed.

Ecology.

Found growing on Sphagnum and mossy cushions at ground level and epiphytically (up to 2.5 m high) in high elevation cloud forest and paramo (observed from 3235 to 3700 m). Plants growing in partially shaded areas to full sunlight. Stems erect to hanging, with flowers often found on or slightly above ground level. Flowers protandrous, commonly with one flower per stem but occasionally two.

Phenology.

Observed in flower in January, March, July, and November. Approximately 20 individual plants with mature flowers were located during an expedition in November of 2022 and fewer individuals with mature flowers were observed in January of 2022. Fruits not documented.

Etymology.

The specific epiphyte, pastazensis, reflects the watershed of the type locality that includes Río Pastaza and adjacent tributaries.

Distribution and preliminary assessment of conservation status.

Bomarea pastazensis is endemic to the upper Pastaza watershed, located in the eastern Andean slopes of Ecuador. The first documented population was inside Cerro Candelaria Reserve in Tungurahua province (Fig. 3 ). The Cerro Candelaria Reserve is a private reserve of 2800+ hectares managed by Fundación EcoMinga. It is bordered on the north by EcoMinga’s Naturetrek Reserve, and the south by Parque Nacional Sangay. Along with Fundación EcoMinga’s Machay and Naturetrek Reserves to the north, it forms a protected corridor between Parque Nacional Sangay and Parque Nacional Llanganates. Cerro Candelaria Reserve was founded by Fundación EcoMinga in 2007 and financed by the World Land Trust (UK); the majority of the reserve is undisturbed by anthropogenic activity. A diverse flora and fauna has been recorded here, including many endemic species and species of high conservation priority ( Jost 2004; Reyes-Puig et al. 2013), such as Blakea attenboroughii Penneys & L.Jost ( Melastomataceae ) which is endemic to the lower elevation forests of Bosque Protector Cerro Candelaria. Several recently described species in the Orchidaceae share a similar geographic distribution to Bomarea pastazensis (Fig. 3 ), include Teagueia barbeliana L.Jost & Shepard, T. puroana L.Jost & Shepard, T. kostoglouana L.Jost & Shepard, T. lizziefinchiana L.Jost & Shepard, and T. anitana L.Jost & Shepard ( Jost and Shepard 2011; 2017). Additional surveys in Cerro Candelaria and in the surrounding upper Rio Pastaza watershed are likely to yield many more undescribed species, and potentially additional populations of Bomarea pastazensis . The distribution of this species highlights the importance of the Llanganates-Sangay corridor for allowing species gene flow and connectivity among populations ( Ríos Alvear and Reyes-Puig 2015). A second documented population of Bomarea pastazensis was provided by digital images from EcoMinga’s park guard Eduardo Peña (July 2023) in the Llanganates National Park, north of Río Pastaza (Fig. 3 ). We calculated the AOO=12 km2 from Peña’s observation and the type collection (Fig. 3 ). Based on the available information and according to the IUCN Red List criteria ( IUCN 2012; IUCN Standards and Petitions Committee 2022), Bomarea pastazensis is preliminarily assessed as Vulnerable (VU) based on a limited area of occupancy (IUCN criterion D2 where AOO <20 km2) and dependence on conservation efforts for its continued survival. The only documented populations of Bomarea pastazensis are located inside protected areas, at elevations that are used for agriculture in unprotected parts of the Pastaza province. Effective conservation of this and the other unique species of the Pastaza watershed will require constant vigilance.

Comments.

Bomarea pastazensis differs from other congeners by a distinctive pattern of three dark spots on the petals (Fig. 2D ), widely opened flowers, and small size. Bomarea pumila and B. pastazensis share similar traits such as their small size in comparison with the rest of Bomarea species, the presence of pubescence throughout their above-surface organs, and the color patterns of the flowers (Figs 2 , 5 ; Table 1 ). B. pastazensis is slightly bigger in size (10-14 cm tall) than B. pumila (5-9 cm tall). In contrast, B. pastazensis is sparsely pubescent at the base of the sepals, while the sepals of B. pumila are uniformly densely pubescent (Fig. 5 ). The petals of B. pumila are not spotted, which differentiates it from B. pastazensis which has a three-spotted pattern on the petals (Fig. 2B ). The two species are geographically isolated with B. pastazensis endemic to the Pastaza watershed on the eastern Andean slopes in central Ecuador (Tungurahua province) and B. pumila from Central Peru to northern Bolivia. Table 1 provides a summary of distribution and useful characters for differentiating B. pastazensis and B. pumila .

Additional specimens examined.

Ecuador. Tungurahua: Cantón Baños, Parroquia Rio Verde , Bosque Protector Cerro Candelaria ( Fundación EcoMinga), upper Pastaza watershed, Cerro Candelaria summit trail, just below paramo, 1°28'39.33"S, 78°17'53.61"W, 3150-3827 m, 1 Jan 2022, N. Exe, M. Johnson & A. Fierro-Minda 2 (GUAY) .

Figures

Figure 2. Bomarea pastazensis A lateral view of flower B front view of flower featuring mature androecium C mature gynoecium D petal E adaxial leaf surface F mature flowers with foliage G habitat H tuberous roots. Photos A by J. L. Clark (J. L. Clark 14839), B-H by N. Exe (N. Exe et al. 2).

Figure 3. Distribution map of Bomarea pastazensis. Red dots indicate collections or observations.

Figure 4. Holotype of Bomarea pastazensis, J. L. Clark 14839 (QCA).

Figure 5. Bomarea pumila A-D field images from Peru E syntype (K! [K 000400912]) of Bomarea pumila of W. Lechler 2240 from Sachapata, Peru. Photos A-D from Lucely L. Vilca Bustamente E from The Herbarium Catalogue, Royal Botanic Gardens, Kew. The Board of Trustees of the RBG, Kew.