Doselia A.Orejuela & Saerkinen, 2022
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publication ID |
https://dx.doi.org/10.3897/phytokeys.202.82101 |
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persistent identifier |
https://treatment.plazi.org/id/B0EFD573-0D35-5F97-BA53-30525F85AC8F |
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treatment provided by |
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scientific name |
Doselia A.Orejuela & Saerkinen |
| status |
gen. nov. |
Doselia A.Orejuela & Saerkinen gen. nov.
Fig. 1 View Figure 1
Diagnosis.
Like Solandra Sw. and Schultesianthus Hunz., but differing from both in having membranous leaves (vs. chartaceous or coriaceous), lacking glandular trichomes, having pendulous inflorescences with long slender peduncles (vs. solitary flowers or short erect inflorescences with thick woody peduncles), distally winged pedicels, and actinomorphic corollas (vs. weakly zygomorphic); differing from Solandra in its smaller corollas (8.5-15 cm vs. 15-40 cm long), flowers borne in groups (vs. solitary), straight filaments and styles (vs. strongly curved and declinate), and 2-locular ovaries (vs. 4-locular); differing from Schultesianthus Hunz. in the chartaceous fruiting calyx with visible venation (vs. a thick, shiny and coriaceous fruiting calyx with no visible venation).
Type species.
Doselia lopezii (Hunz.) A.Orejuela & Särkinen comb. nov. (basionym Markea lopezii Hunz.)
Description.
Hemiepiphytic lianas adhering to the trees by adventitious roots. Stems terete when fresh, irregularly angulate when dry, pubescent with simple, uniseriate multicellular eglandular trichomes, older stems with pale brown and papery bark, often peeling, with broad circular foliar scars left by fallen leaves. Leaves alternate on young stems or tightly clustered appearing sub-opposite in adult branches, simple, broadly elliptic to obovate, membranous, concolorous, sparsely to densely pubescent both abaxially and adaxially with simple, uniseriate eglandular trichomes like those on stem; major veins 3-6 pairs; base attenuate to obtuse, sometimes asymmetric; margins entire to undulate; apex acute, acuminate, or mucronate; petioles well-developed, conspicuously articulate, green. Inflorescences axillary to sub-axillary monochasial cymes, simple to one-branched, occasionally bracteate, usually long-pedunculate and pendulous, 1-7-flowered, pubescent with trichomes as on the stems; peduncles (1.2-) 8.5-50 cm long; bracts absent or if present foliaceous and linear, 5-6 cm long, 1-2 cm wide; pedicels 0.5-3.0 cm long, conical, 5-ribbed, distally thickened and winged in some species, articulated at the base. Flowers 5-merous, actinomorphic, perfect, aestivation valvate in the calyx and cochlear in corolla. Calyx cupuliform, green to whitish-green with purple colouration sometimes on the veins or along the margins only; lobes flat to undulate, 2.4-5.2 cm long, 1-1.5 cm wide, long-triangular to lanceolate, apically long-acuminate to acute, pubescent with simple, uniseriate eglandular, transparent to brown trichomes. Corollas 8.5-15 cm long, the inner corolla diameter from 2.5-5.0 cm, infundibuliform, hypocrateriform to tubular-campanulate, orange, purple, white, yellowish-green with purple veins, sparsely pubescent abaxially with trichomes like those on the calyx; lobes 1.6-4.2 cm long, 1.6-4.3 cm wide, triangular to oblong, spreading to reflexed during anthesis, glabrous to sparsely pubescent, the margins entire to undulate to revolute, the apices acute to obtuse. Stamens 5, equal, included within corolla tube or fully exserted beyond the mouth; filaments 1.7-6.1 cm long, adnate to the base of the corolla, white to purple-tinged, glabrous to pubescent at the point of insertion; anthers 1.4-2.7 cm long, 1.3-1.8 mm wide, elongate, basifixed, not connivent. Ovary conical, 2.9-7.5 mm long, 2.9-7 mm in diameter, light yellow to brown, 2-carpellate, 2-locular, glabrous, with a well-developed 5-lobed light green to pale yellow nectariferous disc; style 5.9-8.8 cm long, straight, glabrous to sparsely pubescent with simple uniseriate trichomes 0.3-0.5 mm long; stigma 2-lobed, ca. 1 mm long and wide, usually clavate. Fruit a conical berry, 1.5-4.4 cm long, 1.5-4.4 cm in diameter, pale to dark green, chartaceous to coriaceous when dry, 2-locular, the exocarp 2-2.8 mm thick; fruiting calyx persistent, the lobes 3-5 cm long, 1.2-2.3 cm wide, appressed and enveloping the berry loosely, fully covering the fruit. Seeds numerous, 2.2-3.6 mm long, 1-1.7 mm wide, subreniform, the testa reticulate, the testa cells rectangular and straight in the outline, the embryo slightly curved, the cotyledons accumbent, slightly longer than the embryo rest, endosperm rather scanty. Chromosome number not known.
Etymology.
The generic name Doselia is derived from the Spanish word “dosel”, meaning canopy. It refers to the hemiepiphytic lianescent habit of all species of Doselia , with branches rising high up to the canopy to the top of tree crowns. The plants can be challenging to see because of their position on top of the tree canopy unless the plants have their showy pendulous flowers.
Distribution
(Fig. 2 View Figure 2 ). Mid-elevation moist Andean forests from 500 to 2,300 m in Ecuador (Provinces of Morona Santiago, Napo, Pastaza) and Colombia (Departments of Antioquia, Boyacá, Caldas, Caquetá, Huila, Putumayo, Risaralda, Santander, Tolima, Valle del Cauca).
Discussion.
Doselia represents a morphologically distinct group of four hemiepiphytic lianas from mid-elevation moist Andean forests with very long branches extending to the forest canopy through adventitious roots. The combination of hemiepiphytic lianescent habit, membranous leaves arranged in tight clusters on adult branches, indumentum consisting of only simple eglandular trichomes, showy actinomorphic flowers arranged in elongated, pendulous, and few-flowered inflorescences, and conical fruits is unique within the tribe.
Within Solandreae, the lianescent hemiepiphytic habit is also known in Solandra and Schultesianthus , with the rest of the tribe mainly being epiphytic or rarely terrestrial shrubs ( Markea antioquiensis clade; Table 1 View Table 1 ). Leaves of all Doselia species are highly clustered on branch tips in whorls of 4-6 similar to species in the Markea antioquiensis clade and some species of Markea (e.g., M. plowmanii Hunz.) and differ from all other genera and species of the tribe where leaves are more spread apart and clearly alternate (Table 1 View Table 1 ). Leaves in Doselia are membranous with simple eglandular trichomes on both surfaces, a character shared with some species of the Markea antioquiensis clade (e.g., M. pilosa S.Knapp; Table 1 View Table 1 ). In many other genera of Solandreae, the leaves are chartaceous (e.g., Hawkesiophyton Hunz., Juanulloa Ruiz & Pav., Merinthopodium Donn. Sm., Solandra and Trianaea Planch. & Linden) or subcoriaceous to coriaceous (e.g., Schultesianthus ) and often have simple glandular and/or dendritic trichomes in addition to the simple eglandular ones (Table 1 View Table 1 ).
Inflorescences in Doselia are long and pendulous (up to 50 cm long), with up to three flowers of which only one or rarely two develops at a time (Table 1 View Table 1 ). Such inflorescences are not typical in the tribe but are observed only in a few other species in Solandreae, including Markea coccinea Rich., Merinthopodium neuranthum (Hemsl.) Donn.Sm., Merinthopodium pendulum (Cuatrec.) Hunz., and Trianaea nobilis Planch. & Linden. Pedicels in some Doselia species are distally winged because the sutures of the calyx are winged and continue onto the pedicel. Distally winged pedicels are also known in some species of the Markea antioquiensis clade (e.g., Markea antioquiensis S.Knapp and Markea pilosa S.Knapp; Table 1 View Table 1 ).
Corollas in Doselia are actinomorphic and showy, similar to species of the Markea antioquiensis clade, but these two groups can be distinguished based on other characters such as growth form, peduncle length, number of open flowers per inflorescence, and floral bract and calyx size (Table 1 View Table 1 ). The two groups also differ in their calyx lobes, where lobes have acute to long-acuminate tips in Doselia but are rounded in the Markea antioquiensis clade. Corollas in the two other morphologically closely related genera Solandra and Schultesianthus are slightly zygomorphic (Table 1 View Table 1 ).
Fruits in Doselia are conical, leathery, and fully covered by the calyx, like those of Solandra , but differ from the latter in being 2-carpellate and 2-locular, in contrast to the 2-carpellate and 4-locular fruits in Solandra (Table 1 View Table 1 ). Fruits in Schultesianthus appear similarly leathery but are globose in shape and covered only partially by an irregularly splitting calyx (Table 1 View Table 1 ). Chromosome number is not known for Doselia , but count numbers in other members of Solandreae, have shown a basic chromosome number × =12 for Dyssochroma Miers ( Piovano 1989; Acosta and Moscone 2000), Solandra ( Campin 1924; Lepper 1982) and Trianaea ( Chiarini et al. 2019). Similar chromosome counts might be expected for Doselia , but further research is necessary to confirm this assumption.
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