Salvia tetramerioides Mart.Gord., Fragoso & García-Peña, 2016

Martínez-Gordillo, Martha, Fragoso-Martínez, Itzi & Peña, María Del Rosario García, 2016, A new species of Salvia section Uliginosae (Lamiaceae), from Oaxaca, Mexico, Phytotaxa 245 (3), pp. 216-222 : 217-221

Salvia tetramerioides Mart.Gord., Fragoso & García-Peña , sp. nov. ( Fig. 1 )

Species insignis inflorescentiis suis a speciebus nobis notis bene distincta ; differt pedunculis 4.2–10 cm longis, rhachidibus 0.6–1.9 cm longis, bracteis decussatis ample ovatis, ciliatis, floribus duobus per nodum, corollarum labio antico 2.2–3.4 mm, labio postico 8.4–8.9 mm.

Type:— MEXICO. Oaxaca: Zapoquila, Montaña Verde , ladera sur del Cerro Chicamole, norte de Guadalupe Membrillos, 1 October 2001, Tenorio & Kelly 21182 (Holotype MEXU!).

Annual herbs, erect stem, 30–40 cm tall, slightly branched; stems pilose with multicelullar trichomes. Leaf blades triangular-lanceolate to lanceolate, 1.7–3.5 × 0.8–1.4 cm, apex acute, margin serrate, base cuneate, upper surface hirsute, lower surface pubescent with appressed hairs, mostly on the nerves, brown spherical glands; petioles 0.1–0.8 cm long. Inflorescences terminal, spiciform, dense, 10.2–14 cm long; peduncle (4.2–) 9.5–10 cm long; rachis (0.6–) 0.8–1.9 cm; occasionally in the mature inflorescence the proximal nodes 0.6–1.1 cm apart. Bracts persistent, two per node, 5–9.1 × 4.1–6.9 mm, decussate, widely ovate, upper and lower surfaces glabrous, apex caudate, margin entire, densely ciliate with multicelullar trichomes, 1–1.5 mm long, base cuneate, purple. Flowers 2 per node; pedicel 1 mm long or less, erect, hirsute. Calyx bilabiate, green, tube 4–5.6 mm long, pilose with appressed hairs, mostly on the nerves, glabrous within; posterior lip 2–3 mm long, 5-veined, 3-mucronate, the middle tooth longer than the laterals, margin ciliate; anterior lip 2 mm long, shorter than the posterior, apex acuminate, margin ciliate. Corolla lilac or blue, tube 3.9–5.3 mm long, straight, the same size or slightly longer than the calyx tube; posterior lip 2.2–3.4 mm long, hirsute, with brown spherical glands, anterior lip 8.4–8.9 mm long, trilobate at the apex, extended. Stamens included in the posterior lip, filament and connective 1.7–2.6 mm long, connective geniculate, with a dorsal tooth near the joint with the filament, ventral surface of the gubernaculum with minute trichomes, geniculum lobate at the apex; filament ending in a tooth; thecae 1.2–1.5 mm long. Nectary horn shorter than the mericarps; style bilobate, 6.4–6.9 mm long, dorsally pubescent, posterior branch at least three times longer than the anterior branch, the anterior branch short and laterally flattened. Mericarps ovoid, 1.6 × 0.9 mm, smooth, brown.

Distribution, habitat and phenology: — Salvia tetramerioides is endemic to Zapoquila, in Oaxaca. It has been collected in oak forests and mixed Quercus -Juniperus forests at 2000 to 2310 m elevation. Flowering and fruiting from September to November.

Etymology: — tetramerioides denotes the morphological similarity of the inflorescences of the new Salvia species to the inflorescences of the species of Tetramerium from the Acanthaceae family.

Discussion: — The most notorious feature of the new species are the broadly ovate floral bracts in a congested disposition, that resemble those of the species from section Membranaceae (Bentham) Epling (1939: 143) , which are reniform and persistent. Nevertheless, when examined in detail, it is noted that the new species has characteristics that are not found in the species of section Membranaceae , such as the posterior lip of the calyx 3-mucronate and a laterally flattened style; this combination of characteristics are distinctive of the taxa from section Uliginosae . Some of the most important characters that were used for species identification in this section are the habit of the plant and the presence of subterranean structures for perennation. Within section Uliginosae two series were recognized by Epling (1939), the first one comprises species with ovate or obovate leaf blades and petioles shorter than 1 cm long; on the other hand the other series contains species with deltoid, rhomboid or linear leaf blades and petioles of 0.8–2 cm long ( Epling, 1939). Following these criteria, Salvia tetramerioides can be placed in the second series with S. laevis Bentham (1833: 251) , which shares with the new species the shape of the leaf blade. Albeit it differs from it mainly by being a perennial herb (vs. annual), with the presence of subterranean structures (vs. absence), 3 flowers per node (vs. 2 flowers per node) and caducous bracts when fruiting (vs. persistent bracts in fruiting) ( Table 1). Other morphologically similar species to S. tetramerioides are: 1) S. pusilla Fernald (1900: 495) , that shares the presence of bracts during fruiting but differs chiefly in characters such as the presence of subterraneous perennation structures, glandular indumentum, and an acute bract apex ( Table 1); 2) S. setulosa Fernald (1901:499) which occasionally presents bracts during fruiting but differs primarily in the presence of 3–8 flowers per node and a longer flower than the new species ( Table 1); 3) S. prunelloides Kunth (1818:289) that also shares the absence of glandular trichomes on the stem and pubescent lower surface of the blade; but can be differentiated by being an herbaceous perennial plant with rhomboid leaves and the presence of 3–6 flowers per node, with bracts absent during the fruiting stage ( Table 1).In the phylogenetic tree obtained by Jenks et al. (2013) section Uliginosae is polyphyletic; hence, our decision of placing S. tetramerioides within this section is provisional, since it is evident that in the near future a complete reevaluation of Epling’s sections ( Epling 1939, 1940, 1941, 1944, 1947, 1951, Epling y Jativa 1966) will be a necessary to ease the study of this species-rich subgenus. A key is proposed here to distinguish it from the species of the sect. Uliginosae growing in Oaxaca.

Additional specimens examined: — MEXICO. Oaxaca: Zapoquila, La Zotolera, E de Guadalupe Membrillos , 2000 m, 4 November 1991, Tenorio et al. 18100 ( MEXU!) ; Guadalupe Membrillos , 2310 m, 18º1’ N, 97º33’ W, 10 September 2001, Tenorio & Alvarado 20848 ( MEXU!) ; Rincón del Capulín, entre los cerros Quiote Blanco y La Zotolera , SE de Guadalupe Membrillos, 1 October 2001, Tenorio & Kelly 21136 ( MEXU!) .

Figures

FIGURE 1. Salvia tetramerioides. A) Plant with branches and inflorescence. B) Inflorescence with peduncle. C) Bract. D) Lateral view of the flower. E) Dissected calyx with style, gynobase and nectary horn. F) Dissected corolla with gubernaculum and staminodes. Illustration drawn from Tenorio et al. 18100 (MEXU) by Ramiro Cruz Durán.