Dahlstedtia colombiana, Trujillo-López, Ana María, Ariza-Cortés, William & Londoño-Echeverri, Yeison, 2024

Trujillo-López, Ana María, Ariza-Cortés, William & Londoño-Echeverri, Yeison, 2024, Dahlstedtia colombiana (Millettieae, Papilionoideae, Fabaceae), a new species and first record of the genus from Colombia and its Seasonally Tropical Dry Forest, Phytotaxa 666 (1), pp. 31-41 : 32-37

Dahlstedtia colombiana A.M. Trujillo, Londoño-Ech. & Ariza-Cortés, sp. nov. ( Figs. 1 , 2 & 3 )

Type:— COLOMBIA. Antioquia. Mun. Antioquia [Santa Fé de Antioquia]: Finca Cotové , 500–550 m, 6°34’0”N, 75°50’0”W, 26 May 2001 (fl. & fr.), J.A. Pérez et al. 1670 (holotype: MEDEL, accession 42523 [!]; isotype: COL, accession 476832 [!]) .

Diagnosis:— Dahlstedtia colombiana differs from morphologically similar D. muehlbergiana ( Hassler 1907: 164) M.J.Silva & A.M.G.Azevedo in Silva et al. (2012: 105) by its leaflet bases truncate to rounded (vs. decurrent, rarely cuneate), leaflet secondary veins not reaching at the secondary marginal vein (vs. secondary veins reaching at the secondary marginal vein), shorter secondary bracts 1.4–1.8 mm long (vs. 2.3–2.9 mm long), longer flowering pedicels 3.2–4.2 mm long (vs. 2–2.1 mm long), shorter bracteoles 1.1–1.5 mm long (vs. 3.7–4.1 mm long), wing petals obovate to oblanceolate (vs. semi-elliptical), keel petals elliptic to oblong (vs. ovate), shorter wing petal claws 2.4–3.5 mm long (vs. 5.2–6 mm long) and fruits khaki colored, silky (vs. reddish brown, velvety).

Trees 7–20 m tall, branchlets terete, striate, silky-pubescent, glabrescent, lenticellate; stipules (0.8–)1–1.7 × 1.4–2.7 mm, ovate, obtuse and straight apically, silky abaxially, glabrous adaxially, persistent, margin ciliate. Leaves with 9–11 opposite leaflets; petiole (5.6–) 6.4–10.5 cm long, silky-pubescent, glabrescent, slightly canaliculate; rachis (7–) 9.8–20.5 cm long, silky-pubescent, glabrescent, slightly canaliculate, striate; distance between leaflets pairs (1.6–) 2.3–4.8 cm long; petiolules 5–10.1 mm long, silky-pubescent, glabrescent, slightly canaliculate; leaflet blade 4.5–12.4 × 3.9–7.9 cm, ovate to elliptic, occasionally orbicular to obovate, basally obtuse, truncate to rounded, symmetrical at base in terminal ones, asymmetrical at base in lateral ones; apically acute to obtuse, straight to acuminate or rounded to emarginate; silky-pubescent on both surfaces, glabrescent adaxially; midvein, secondary and tertiary veins raised abaxially; adaxially midvein and secondary veins slightly raised to impressed, tertiary veins impressed; secondary veins 6–11 pairs, eucamptodromous, forming an angle of 33–80° with the midvein, marginal secondary vein present, secondaries not reaching at the marginal one, intersecondary veins present; tertiary veins percurrent; margin entire, slightly revolute. Panicles axillary, usually ramiflorous in leafless branchlets, solitary; axes silky-pubescent, glabrescent; primary bracts caducous, not seen; peduncle (1.2–) 7.9–12.9 cm long; rachis (5.8–) 10.4–20.6 cm long, angulate; secondary bracts 1.4–1.8 × 1.2–1.6 mm, ovate, acute and straight apically, silky-pubescent abaxially, glabrous adaxially, caducous; secondary axes (0.5–) 2.1–8 cm long; tertiary bracts 1.7–1.8 × 0.6–0.9 mm, ovate to elliptic, acute and straight apically, pubescent abaxially, glabrous adaxially, early caducous; flowering pedicels 3.2–4.2 mm long (fruiting ones 4.1–7 mm long), terete, silky, glabrescent; bracteoles 2 at the apex of pedicel, opposite, each 1.1–1.5 × 0.5–0.7 mm, ovate, acute and straight apically, silky-pubescent abaxially, glabrous adaxially, caducous in anthesis. Flowers solitary in each node, lilac to purple in vivo; calyx and corolla sometimes with discrete secretory cavities, each ca. 0.1 mm diam., orbicular, irregularly distributed when present; hypanthium 2.6–3.1 mm high, obconical, zygomorphic, silky; calyx 4.8–6.6 × 6.3–7.5 mm, cupular, gibbous vexillary at the base, silky abaxially, glabrous adaxially, 4-lobed; vexillary lobe broadly ovate, reflex and emarginate apically; carinal lobes 3, ovate, straight, acute, the central longer than the lateral ones; standard petal 11.3–14.9 × 10.1–13.2 mm (including claw), above the claw orbiculate to elliptic, basally reflex, slightly cordate, apically reflex, emarginate, recurved, 1.5–2.2 × 0.8–1.3 mm unguiculate, silky abaxially, glabrous adaxially, bearing transversal and linear callosities adaxially at apex claw; wing petals 14.3–17.4 × 3.7–4.5 mm (including claw), above the claw obovate to oblanceolate, straight to slightly curved, basally decurrent, apically obtuse, rounded, 2.4–3.5 mm long unguiculate, silky at the center abaxially, glabrous adaxially, claw twisted; keel petals 13.2–15.1 × 3.5–3.9 mm (including claw), above the claw elliptic to oblong, straight to slightly curved, basally obtuse, truncate, apically obtuse, rounded, 4.2–5.4 mm long unguiculate, silky abaxially, glabrous adaxially, with a pocket on the central basal region above the claw; androecium pseudo-monadelphous, bicallose basally, sparsely silky abaxially, denser to the apex, glabrous adaxially; longer filaments 12.2–14.3 × 1.9–3.3 mm, staminal tube reaching to ¾ of its length; anthers 0.7–0.9 × 0.5–0.7 mm, dorsifixed, ovoid, sparsely silky abaxially, glabrous adaxially, with a tuft of trichomes basally; disc ca. 1 mm high, glabrous, gynoecium 12.5–14.2 × 0.9–1.5 mm (including gynophore), densely silky, stipitate; gynophore ca. 1 mm long, ovary 6.7–7.9 mm long, 1–4 ovulate; ovules reniform, compressed laterally; style 4.6–7.5 mm long (including stigma). Fruits samaroid, 11.3–16.2 × 3.9–5.1 cm, elliptic to oblong, acute and decurrent basally, acute and acuminate apically, flat, silky, khaki colored, indehiscent, vexillary margin slightly winged, 1 or 2 seeds per fruit. Seeds 2.4–2.6 × 1.5–2 cm, reniform, glabrous, smooth.

Distribution and habitat:— Dahlstedtia colombiana is endemic to Colombia, where it has been collected in the department of Antioquia in the municipalities of Andes, Betulia, Ebéjico, Jericó, Santa Fé de Antioquia, Sonsón and Venecia and in the department of Caldas in the municipality of Norcasia ( Fig. 4 ). Specimens from Medellín city come from two mature individuals that grow in the Ciudad Universitaria Campus of the University of Antioquia, which are probably planted. The locality of the specimens collected by Jose Celestino Mutis is unknown (see discussion).

The new species inhabits seasonally tropical dry forests of northern inter-Andean valleys (about this STDF see Pennington et al. 2009, DRYFLOR 2016) on the Cauca River Valley and Magdalena River Valley biogeographic regions, at 350–1000 m of elevation.

Phenology:— Flowering in April to July and fruiting in January, April to July and November.

Etymology:— The epithet colombiana means “from Colombia ”. Indicating that so far it is the unique species of the genus recorded from Colombia.

Conservation status:— Dahlstedtia colombiana has an area of occupancy (AOO) of 40 km 2, an extent of occurrence (EOO) of 5195 km 2, and has eight known subpopulations. All subpopulations occur outside of protected areas and are located less than 5 km from an urban center. The species is found in very small and fragmented forest patches (<200000 m 2), or as isolated trees in pastures. Dahlstedtia colombiana inhabits in the dry forest in Colombia, which is considered as the more disturbed ecosystem inside the country, because it only has 8 % of original cover ( García et al. 2014). For these reasons D. colombiana is here proposed under “Vulnerable” VU category according to criteria B1ab(iii) + 2ab(iii).

Additional specimens examined:— COLOMBIA. Antioquia. Mun. Andes: 1000 m, 5°45’32”N, 75°54’2.02”W, 4–14 November 2017 (fr.), A.M. Trujillo & A. Montes 25 ( HUA). Mun. Betulia: 500–620 m, 6°14’10.83”N, 75°51’42.99”W, 20 May 2013 (fr.), J.M. Campo 2240 ( COL). Mun. Ebéjico: Hacienda Curumé, Km 55 vía Santa Fe de Antioquia-Bolombolo , 505 m, 6°22’30.40”N, 75°50’24.71”W, 13 July 2022 (im. fr.), J.M. Cano 2 ( HUA, JAUM, TOLI, UDBC) ; 630 m, 6°22’17.87”N, 75°50’14.15”W, 1 June 2023 (fl.), J.P. Tobón & J. Cano 4431 ( JAUM). Mun. Jericó: Bariloche , 941 m, 5°58’16.83”N, 75°52’38.78”W, [5°47’46.19”N, 75°42’11.90”W], 24 January 2019 (fr.), D. Arbeláez et al. 1500 ( HUA) ; Sector Puente Iglesias, vía a la Pintada, cerca al peaje, 612 m, 5°48’40.37”N, 75°41’19.91”W, 18 May 2022 (fl.), J. Colorado & I.C. Guarín 1113 ( HUA). Mun. Medellín : UdeA, Ciudad Universitaria , 1500 m, 11 July 2018 (fl.), M. Herrera-Palma 362 ( HUA) ; Universidad de Antioquia, Ciudad Universitaria, Entre los bloques 9 y 10, 1460 m, 6°15’57.78”N, 75°34’12.40”W, 18 April 2023 (im. fr.), Y. Montoya et al. 587 ( HUA) ; ibid., 6°15’57.56”N, 75°34’11.19”W, 15 June 2023 (fl. & fr.), Y. Montoya et al. 588 ( HUA). Mun. Sonsón: Vereda Las Brisas Causal Abajo, Puente La Nubia , Cuenca del rio Arma , 1030 m, 5°39’16.40”N, 75°21’59.94”W, 5 July 2013 (fr.), J.P. Tobón et al. 780 ( MEDEL). Mun. de Venecia : Orilla de la carretera, 1 km antes de llegar al corregimiento de Bolombolo, 600 m, 5°57ʹ0”N, 75°51’0”W, 30 June 1997 (fr.), Estudiantes Botánica taxonómica MEDEL-1997 95 ( MEDEL). Caldas. Mun. Norcasia: Zona Embalse, transición bh-T y bs-T, 350–650 m, 5°35’52.2”N, 74°53’44.4”W, 6 April 2002 (fl.), W. Vargas 9409 ( FAUC). S. loc., s.d., 1783–1808 (fr.) Mutis 4306 (MA-666549 [digital image], MA-666550 [digital image], MA-666551 [digital image], MA-666552 [digital image], MA-666553 [digital image]) .

Figures

FIGURE 1. Holotype of Dahlstedtia colombiana.

FIGURE 2. Dahlstedtia colombiana: A. Flowering branchlet, B. Leaflet abaxial surface, C. Floral bud at left, anthetic flower lateral view at right, D. Bracteole, adaxially at left, abaxially at right, E. Calyx manually opened, abaxial surface, F. Corolla, G. Androecium, H. Androecium manually opened, adaxial surface, I. Anthers, abaxially at left, adaxially at right, J. Hypanthium, disc and gynoecium, K. Fruit, L. Seed. (A, B, E, I, K, L from J.A. Pérez et al. 1670; C—right, F, G, H, J from Y. Montoya et al. 588; C—left, D from J. Colorado & I.C. Guarín 1113. Illustration by Ana Cristina Pareja, HUA illustrator).

FIGURE 3. Dahlstedtia colombiana: A. Vegetative branchlet, B. Inflorescence with detail of second-order axis, C. Fruiting branchlet, D. Flower: Petals at left, lower view at right top, calyx and androecium lateral view at right bottom, E. Fruit at left, fruit indumentum at right top, and seed at right bottom. (A, C, from Y. Montoya et al. 587; B, from J.P. Tobón & J. Cano 4431; D, E, from Y. Montoya et al. 588. Photographs A, C, by H. David; B, by Juan P. Tobón; D, E, by A.M. Trujillo. Composed photograph by A.M. Trujillo).

FIGURE 4. Geographical distribution of Dahlstedtia colombiana (* indicating the locality of planted individuals).