Salvia rhizomatosa J.G.González, Art.Castro & H.Ávila, 2020

González-Gallegos, Jesús Guadalupe, Castro-Castro, Arturo & Ávila-González, Heriberto, 2020, Salvia rhizomatosa (Lamiaceae) a new species from Sierra Madre Occidental in Durango, Mexico, with a synopsis of Salvia sect. Brandegeia, Phytotaxa 434 (3), pp. 255-269 : 265-266

5. Salvia rhizomatosa J.G.González, Art.Castro & H.Ávila , sp. nov., Figures 2M–2O , 3 , 4

Salviae oresbiae affinis, sed a qua imprimis differt foliis calycibusque nullo modo glutinosis, calycis labio supero 5-nervatis, corollis atroviolaceis, corollae tubis rectis prope basin, corollae labio infero, connectivo et stylo longioribus, et nuculis grandioribus.

Type: — MEXICO. Durango, Pueblo Nuevo: Rancho Pericos, km 7.5 de la brecha entre La Peña y la Mesa del León, 23º34’48.5’’N 105º20’3.26’’W, elev. 2498 m, 5 September 2019, A. Castro-C. et al. 4523 (holotype CIIDIR!, isotypes BUAP!, IBUG!, HUAA!, IEB!, MEXU!, USON!, ZEA!).

Perennial herb, decumbent, subscapose, rhizomatous, 7–30 cm tall; stems sparsely to densely hispidulose, with heterogenous hairs in length and thickness, to covered with appressed retrorse hairs, or occasionally scarcely hirsute. Leaves subcoriaceous, not conspicuously aromatic, with petioles (3–) 5–11 mm long, with similar pubescence to that of the stems; leaf blade elliptic, elliptic-lanceolate, ovate, subdeltoid to ovate-lanceolate, 2.4–3.9(–5) × 1–1.9 cm, apex acute to rounded/obtuse, base shortly cuneate, margin entire to obscurely serrate, revolute, often ciliate, both surfaces glabrous except by the main vein which is sometimes hispidulous, with tiny yellowish glandular dots beneath. Inflorescences in racemes (3.5–) 10–21.3 cm long, with 2–7 floral nodes, each one 2-flowered, the lowermost separated by (1.9–) 2.8–4.7 cm from each other, floral axis sparsely to moderately hispidulous. Floral bract narrow lanceolate to ovate-lanceolate (those of the lowermost floral nodes, sometimes transitional in shape with the leaves), mostly divaricate, late deciduous, (5.2–)8–11.7 × (1.2–) 2.1–3.8 mm, apex acute to caudate, base truncate, margin entire and ciliated, both surfaces essentially glabrous. Flowers with pedicels 3.4–4.5 mm long, densely hispidulous. Calyx 11.2– 13.2 × 6.2–8.4 mm, hispidulous on the veins, upper lip entire and 5-veined. Corolla dark violet, pilose on the dorsal surface of the tube, the upper lip and ventral portion of the lower one; corolla tube ventricose, straight at the base, 15.8–18(–20) × (4.3–) 6.6–8.2 mm, base internally epapillate; upper lip (7.2–) 10–11.3 mm long; lower lip (11–)15– 19.7 × (11–) 18.6–25.9 mm, reflexed, with two longitudinal white strands near the throat as nectar guides. Stamens included; filament 2.9–4 mm long; connective (11.3–) 12.5–15.6 mm long, ventrally ornate with a rudimentary straight tooth near midpoint; thecae (2–) 2.5–3.1 mm long; a pair of small staminodes above and behind filament insertion, filiform. Gynobasic horn 0.9–1(–1.5) mm long; style 2.1–2.8 cm long, dorsally and ventrally pilose towards the apex, upper stigmatic branch longer, the lower one acute. Mericarp ovoid, 1.3–1.6 × 1.2–1.4 mm, light brown and irregularly marbled with a darker tone, glabrous, smooth.

Distribution, habitat and phenology: — Salvia rhizomatosa is known exclusively from the middle portion of Sierra Madre Occidental in western Durango ( Figure 1 ). The three known subpopulations are found in pine-oak forest and adjacent areas with apple orchards and corn fields. The plants were found in flat and open spaces of the forest, on acid and sandy soils. It shares habitat with Arbutus tessellata P.D.Sørensen , Calochortus ownbeyi M.A.García-Mart., Aarón Rodr. & H.P. McDonald, Cosmos palmeri B.L.Rob. , Phaseolus pauciflorus Sessé & Moc. ex G.Don , Pinus lumholtzii B.L.Rob. & Fernald , Quercus sideroxyla Bonpl. , and Salvia lavanduloides Kunth. It occupies an elevational range from 2420–2498 m. As far as known, S. rhizomatosa flowers and fructifies in a short period of time from late August until mid-September.

Preliminary conservation status: — Salvia rhizomatosa is represented by 3 collections from very close localities to each other ( Figure 1 ). The EOO is 0.019 km 2, and the AOO is 4 km 2, based on cells of 2 × 2 km. According to these results and following the IUCN (2012) criteria (EOO and AOO estimated to be less than 100 km 2 and 10 km 2, respectively), a preliminary Red List Category is proposed [CR/B1a + B2a].

Etymology: —The specific epithet makes reference to the remarkable ability of this new species to produce long rhizomes as a strategy to colonize the land.

Additional specimens examined (paratypes): — MEXICO. Durango. Mun. Pueblo Nuevo: Rancho Pericos , km 7 de la terracería entre La Peña y La Mesa del León, 23º34’42.4’’N 105º19’50.7’’W, elev. 2448 m, 5 September 2019, A. Castro-C. et al. 4520 ( CIIDIR!, IBUG!, IEB!) ; Rancho Pericos , km 8.5 de la terracería entre La Peña y La Mesa del León, 23º34’41.3’’N 105º19’’’ W, elev. 2420 m, 5 September 2019, A. Castro-Castro et al. 4522 ( CIIDIR!, IBUG!, IEB!, MEXU!, USON!) .

Discussion: —The morphological characters of Salvia rhizomatosa clearly justify its placement into Salvia sect. Brandegeia according to Epling’s sectional classification ( Epling 1939, 1940, 1941, 1944, 1947, 1951, 1960, Epling & Mathias 1957, Epling & Játiva 1963, 1966, 1968). However, it slightly deviates from this in having dark violet corollas instead of red to magenta and straight corolla tubes at the base instead of invaginated ( Epling 1939). Nonetheless, corolla color is quite labile in some of the Salvia sections, even there is at least one specimen of Salvia angustiarum with dark violet corollas (M. Harker et al. 3639, IBUG!). Hence, corolla color by itself does not prevent the assignment of the new species to the section, neither the lack of the invagination because this is a minor deviation against the straightforward match with the other characters circumscribing the section. Salvia rhizomatosa is morphologically most similar to S. oresbia , but it can be distinguished by the non-glutinous leaves and calyces, upper calyx lip with 5 veins instead of 7, dark violet corolla (vs. magenta to pink), straight corolla tube at the base (vs. invaginated), longer lower corolla lip [(11–)15–19.7 vs. 6.8–8.2 mm], longer connective [(11.3–)12.5–15.6 vs. 9.7–12.1 mm], longer style (21–28 vs. 17–20.5 mm), and shorter mericarps (1.3–1.6 × 1.2–1.4 vs. 2.5–2.8 × 1.6–2.6). Additionally, these two species grow in high contrasting biogeographic provinces and environments, whereas S. oresbia grows in the Mexican High Plateau in xeric forests, S. rhizomatosa is found in a high humid area set in Sierra Madre Occidental.

Figures

FIGURE 1. Distribution of Salvia angustiarum (triangles), S. blepharophylla (diamonds), S. buchananii (squares), S. oresbia (asterisks) and Salvia rhizomatosa (stars).

FIGURE 2. Photographs of the species of Salvia sect. Brandegeia showing different views of the flower and habit. A–C S. angustiarum. D–F S. blepharophylla. G–I S. buchananii. J–L S. oresbia. M–O S. rhizomatosa. Photographs: Arturo Castro-Castro (A–C); Leccinum J. García-Morales (D–F); Rolando Uria (G–I); Jesús G. González-Gallegos (J); Marcos B. Núñez-Oberg (K & L); Heriberto Ávila-González (M–O).

FIGURE 3. Salvia rhizomatosa J.G.González,Art.Castro & H.Ávila.A habit. B leaves. C calyx and floral bracts. D & E lateral and frontal view the flower. Photographs: Heriberto Ávila-González (A, E) and Arturo Castro-Castro (B, C, D).

FIGURE 4. Salvia rhizomatosa J.G.González, Art.Castro & H.Ávila. A habit. B floral bract. C calyx. D corolla. E connective and theca. F upper portion of the style. G mericarp (Drawn by Jesús G. González-Gallegos).