Triphora gallegosii Figueroa, Zabalgoitia, Velázquez-R. & R. Jiménez, 2023

Figueroa, Dante S., Zabalgoitia, Alejandro, Velázquez-Ríos, Perla, Muñiz-Castro, Miguel Á., Jiménez-Machorro, Rolando, Guerrero-Hernández, Ricardo & Huerta-Galván, Oassis, 2023, A new species of Triphora (Orchidaceae: Triphoreae, Triphorinae) from Mexico, Phytotaxa 599 (2), pp. 89-99 : 91-96

Triphora gallegosii Figueroa, Zabalgoitia, Velázquez-R. & R. Jiménez , sp. nov. ( Figures 1–2 )

Type:— MEXICO. Jalisco: Municipio de Mixtlán, en las inmediaciones del puente “ Los Tablones ”, a un lado de la carretera Ameca-Mascota a 3.9 km al noreste de Mixtlán , 20°27’44.59”N, 104°22’44.01”W, alt. 1724 m, 19 September 2019, A. Zabalgoitia, et al. 680 (holotype: IBUG!; isotype: AMO!).

Triphora gallegosii is similar to T. gentianoides and T. wagneri in having lips with three longitudinal and verrucous lines, and in the size of floral parts. However, in T. gallegosii these lines vanish towards the middle of the central lobe (vs. reaching the apex of the central lobe), in addition, T. gallegosii has resupinate flowers (vs. non-resupinate). Furthermore, T. gallegosii differs from T. gentianoides in having 1–4 flowers (vs. 3–10 flowers), sepals and petals magenta at the apex, decreasing in intensity towards the middle portion and green at the base (vs. ranging from green to white, commonly with some brown or reddish tones on sepals), a white lip with a magenta spot at the tip of the central lobe (vs. white to pale green), green warts on the lip lines (vs. green and white warts), lateral lobes of the lip with entire margins (vs. erose to nearly lacerate), a column with a magenta apex and whitish towards the middle portion with a green base (vs. magenta to brown at the apex and the rest green or yellowish-white), a magenta anther (vs. yellow), leaves of 3.5–13 × 2–6 mm (vs. 10–18 × 5–10 mm), solitary growth habit (vs. growing in clusters), and blooming between August and September (vs. June and August). It also differs from T. wagneri in having 1–4 flowers (vs. 1 flower), lateral lobes constricted at their junction with the central lobe and with an acute apex (vs. unconstricted and obtuse), and blooming between August and September (vs. April).

Description:— Geophyte herb, inconspicuous, 10.0– 20.4 cm tall. Formed by a red-like stem attached to a corm. Corm 18.5–37.5 × 9.0– 15.3 mm, oblong-ellipsoid to oblong-ovoid, glabrous, fleshy, white. Roots 1–2 mm diameter, from the base of the stem, glabrous, cylindrical, eventually producing new corms. Stem 7.0–15.5 × 0.1–0.3 cm, cylindrical, fleshy, glabrous, erect, the hypogeal part 4.0– 6.5 cm long, with a shoot bud towards the middle of this, white, the epigeal part 4.6–15.9 cm tall, wine red. Leaves 2–3, distributed along stem, scale-like, adpressed to the stem; blades 3.5–13 × 2–6 mm, oblong-ovate, semiamplexicaul, the apex acute, the margin entire, the adaxial face wine red to slightly green, the abaxial face wine red. Inflorescence 2.5–4.0 cm long, terminal, solitary, racemose. Flowers 1–4, successive, open one at a time, short-lived, resupinate in frontal position, sepals and petals magenta at the apex, decreasing in intensity towards the middle portion, green at the base, lip white, with a magenta spot at the tip of the central lobe, with green warts. Floral bracts 5–10 × 4.0– 6.9 mm, ovate, amplexicaul, acute, the margin entire, the same color as the leaves. Ovary 6–15 mm long including pedicel, 2–7 × 1–2 mm (without the pedicel), dilated towards the perianth, 6-costate, striated, slightly verrucose, growing faster after pollination; pedicel 4–6 × 0.8–0.9 mm, cylindrical, up to 12 mm long after anthesis. Sepals elliptic to narrowly elliptic, acute, the margin entire, 3-veined; dorsal sepal 6.0–13.6 × 2–3 mm; lateral sepals 8.0–11.6 × 2–3 mm, oblique, falcate, concave. Petals (7.5–) 9.0–12.3 × 1.5–2.7 mm, projecting forward covering the column, narrowly elliptic, falcate, concave, unguiculate at the base, the claw 1.2 mm long, the apex acute, the margin entire, 3-veined. Lip 6.5–10.7 × 3.8–5.8 mm, trilobate, unguiculate and cuneate at the base, claw 1.0–1.5 × 1 mm, cuneate base 2.6–4.0 × 1.5–3.5 mm, with three longitudinal green lines arising from the base towards the middle part of the central lobe, becoming undefined and verrucous without reaching the apex; lateral lobes 1.1–1.9 × 0.9–1.5 mm, not exceeding more than a half of the length of the central lobe, semiovate to lanceolate, falcate, projected upwards surrounding the column, the apex acute, margin entire; central lobe 2.5–4.0 × 2.0– 3.2 mm, constrained at the union with the lateral lobes, obovate, the apex rounded, margin undulate and minute papillose. Column 5.5–9 mm long, elongate, slightly arching, glabrous, magenta at the apex, decreasing in intensity towards the middle portion, green at the base. Anther incumbent, with a granular surface, magenta. Pollinarium ca. 1 × 1 mm, with two pollinia; pollinia oblong from frontal view, reniform from lateral view. Rostelum trilobate, the lateral lobes thinner and longer than the central one. Stigma 1.5–2.5 mm long, oblong, concave, scarcely papillae with margins slightly raised, white. Capsule 8–15 × 3.5–7.9 mm, obovoid, pendent, wine red before opening; pedicel 4.1–10.0 mm long. Seeds not seen.

Distribution and ecology:— This species is currently known from central, western, and northwestern Mexico in the states of Jalisco, Sinaloa, Michoacan, and Estado de Mexico ( Figure 3 ), but there are probably more intermediate populations among known localities. From a biogeographic perspective, this species is distributed in the Trans-Mexican Volcanic Belt, the Sierra Madre del Sur and Sierra Madre Occidental provinces proposed by Morrone et al. (2017).

Triphora gallegosii inhabits in oak, oak-pine or pine-oak forests with a marked dry season, in low light conditions among leaf litter in well-drained soils. The elevational range of the populations known to date is between 1500 and 2000 (–2300) m a.s.l. At the type locality, it grows along with Pinus oocarpa Schiede ex Schlechtendal (1838: 491) , Pinus douglasiana Martínez (1943: 4) , Quercus resinosa Liebman (1854: 182) , Comarostaphylis sp. Zuccarini (1837: 331). Achimenes glabrata ( Zuccarini 1832: 99) Fritsch (1894: 174) , Calochortus occidentalis M.A. García-Martínez & Aarón Rodríguez (2018: 133), Prochnyanthes mexicana ( Zuccarini 1837: 319) Rose (1903: 14) , Chaetium bromoides (J. Presl 1830: 324) Bentham ex Hemsley (1885: 503) , Habenaria sp. Willdenow (1805: 44), and Tristachya sp. Nees (1829: 458). In other populations, the presence of Quercus eduardii Trelease (1924: 121) , Agave maximilliana , Calliandra hirsuta (G. Don 1832: 395) Bentham (1875: 554) , Ximenia parviflora Bentham (1839: 7) , Eysenhardtia sp. Kunth (1824: 489) Sedum jaliscanum S. Watson (1890: 148) and Bletia roezlii Reichenbach (1877: 7) has been recorded.

The specimens with flowers were collected between August and October, during the rainy season. We observe that most individuals bloom simultaneously within the same population. Although we have recorded the presence of 1–4 flowers per individual, only 1–2 bloom at the same time. The aboveground vegetative parts disappear in the dry season. Immature capsules were found in September. We have visited the type locality during the flowering time in different years and we have not found any specimens, which leads us to think that the species does not emerge every rainy season.

Etymology:— This species is named after Dr. Jesús Guadalupe González-Gallegos, dear friend and researcher of the CIIDIR herbarium who has contributed substantially to the floristic knowledge of western and northwestern Mexico.

Additional specimens examined (paratypes):— MEXICO. Estado de México: Municipio de Ocuilan, Mexicapa, 30 July 2008, J. H. Nava Bernal 223 (AMO!); Municipio de Valle de Bravo, camino de Temascaltepec a Valle de Bravo, 6 September 2013, D. Szeszko sub R. Jiménez 2901 (AMO!, illustration voucher); 18 October 2006, D. Szeszko s.n. (AMO!; non-labeled material); 9 September 2007, D. Szezsko 54 (AMO!; non-labeled material). Jalisco: Municipio de Atenguillo, Km 38–39 de la carretera San Vicente-Volcanes entre Tierras Blancas y Fresno Hueco, 20°15’2.5”N, 104°29’10”W, 1931 m, 17 August 2012, A. Rodríguez et al. 6744 (IBUG!); Municipio de Ayutla, km 19.3 del camino Ayutla-San Miguel de la Sierra, 20°07’21.1”N, 104°29’01.9”W, 1837 m, 15 September 2019, D. S. Figueroa & R. Guerrero-Hernández 393 (IBUG!, AMO!). Michoacán: Municipality Tancitaro, on road from Tancitaro to Apatzingan, 17 August 1940, W. M. C. Leavenwoerth (F!). Sinaloa: Municipio de Concordia, El Carrizo, carretera Mazatlán-Durango, 23°31’27.56”N, 105°50’11.95”W, 1926 m (georeferenced), 29 August 1988, R. Vega et al. 2909 (MEXU!).

Other records:— MEXICO. Jalisco: J. G. Gonzáles-Gallegos s.n. (INaturalist observation: 1604925 image!). Sinaloa: M. G. Millán-Othero s.n. (INaturalist observation: 131170951 image!).

Conservation status:— Triphora gallegosii is only known from eight locations ( Figure 3 ). The primary risk factors for this species and its habitats are extensive livestock grazing, expansion of the agricultural frontier, invasive species such as exotic grasses, severe forest fires, logging, drier soil conditions due to forest clearing, and global warming. Based on IUCN Red List guidelines and criteria B2ab(iii) ( IUCN Standards and Petitions Committee 2022) Triphora gallegosii could be considered in the category of Vulnerable (VU), because the number of its known locations is <10 [condition B2(a)], its scarce eight locations have an estimated area of occupancy (AOO) of only 32 km 2 (<2000 km 2, B2 criterion), and an estimated continued decline of area and quality of habitat [condition B2(b)(iii)]. Nevertheless, there are probably more intermediate populations among the known localities in an extent of occurrence (EOO) of 127,550.4 km 2.

Taxonomic Discussion:— This new species is morphologically similar to T. wagneri and T. gentianoides , with whom it shares the presence of scale-like leaves, similar sizes in floral parts, and lips with three longitudinal and verrucous lines. However, T. gallegosii differs from both by many characters (see Table 1 ), mainly present in flowers, as the shape and length of the lines of the lip, the position and number of flowers, and their phenology. Also, it differs from T. wagneri by having a constricted central lobe and lateral lobes with an acute apex (vs. not constricted and obtuse apex), and from T. gentianoides by having an entire margin in the lateral lobes (vs. erose to nearly lacerate), a column with a magenta apex and whitish towards the middle portion with a green base (vs. magenta to brown at the apex and the rest green or yellowish-white), a magenta anther (vs. yellow), leaves of 3.5–13 × 2–6 mm (vs. 10–18 × 5–10 mm), and by having solitary growth (vs. growth in clusters). In addition, while T. gallegosii can be found in the highlands of central, western and northwestern Mexico, T. gentianoides is distributed in the lowlands of southeast Mexico, Central America, the Caribbean islands and the state of Florida in the USA. On the other hand, T. wagneri is distributed in Central America. In our herbarium review we could not find a single reliable specimen of T. wagneri due to the lack of dissected flowers or because the material was in poor condition, so our comparison between this species and T. gallegosii was based on a drawing of the holotype (AMES, barcode: HUH00090830 image!) and the original description of the species. Medley (1996) cites some specimens of T. wagneri from the state of Michoacan, but it is more probable that these specimens belong to T. gallegosii , since habitat description, phenology and distribution fits better with this species.

Sympatric populations of T. gallegosii and T. trianthophoros or T. mexicana may exist, since distribution ranges overlap. The flowers of these three species may appear similar, but T. gallegosii can be easily distinguished from these two by its reddish stems and its scale-like leaves.

The presence of mycorrhizae has been reported in some species of Triphora (including T. gentianoides ) and other genera in Triphorinae ( Carlsward & Stern 2009). Ongoing research on mycoheterotrophy in T. trianthophoros using isotopic evidence has also shown that this species is partially mycoheterotrophic (Brandon Corder, pers. comm., 2023). Scale-like leaves and reddish colorations on stems and leaves may indicate some degree of mycoheterotrophy ( Cameron & Leake 2007), as in other groups of orchids (Merckx et al. 2012, Feng et al. 2016), so it is possible that T. gallegosii also has some type of relationship with fungi. Further studies (e.g. analyzing isotope signatures) could corroborate this hypothesis.

Figures

FIGURE 1. Triphora gallegosii. A. Flowering plant B. Flower from front C. Flower from side D. Flower in oblique view E. Dorsal sepal F. Petal G. Lateral sepal H. Lip I. Lip surface J. Margin of the central lobe K. Flower from side with petals and sepals removed showing the lip and the column in natural position L. Column from front M. Column from side N. Pollinarium from front O. Pollinarium from back. Drawing by R. Jiménez-Machorro from D. Szeszko sub R. Jiménez 2901.

FIGURE 2. Triphora gallegosii. A. Flower at anthesis B. Flower dissection showing sepals, petals and lip C. Lip showing its shape at anthesis D. Corm E. Dorsal and lateral view of column F. Adaxial and abaxial surface of a leaf G. Fruits. Photos by A. Dávalos-Martínez (A, D, F), A. Zabalgoitia (C, E, G) and D. Figueroa (B).

FIGURE 3. Known localities of Triphora gallegosii.