Hyptis macvaughii J.G.González & Art.Castro, 2014

González-Gallegos, Jesús Guadalupe, Castro-Castro, Arturo, Argüelles, Alejandra Flores- & Romero-Guzmán, Ariosto Rafael, 2014, Discovery of Hyptis pseudolantana in Jalisco and Michoacán, and description of H. cualensis and H. macvaughii (Ocimeae, Lamiaceae), two new species from western Mexico, Phytotaxa 163 (3), pp. 149-165 : 158-162

Hyptis macvaughii J.G.González & Art.Castro sp. nov. ( Figs. 1 , 4 and 5 )

Hyptis subtilis Epling affinis sed indumento trichomatum ramosis, petiolis plus minusve brevioribus, cymis sessilibus, plus floribus per verticillastum, pedicellis longioribus, calycum dentibus in florem et in fructum plus minusve brevioribus, corollarum tubo longiore, stylo longiore, plus nuculis fertilibus per florem et magnioribus differt.

Type:— MEXICO. Nayarit. Compostela: 3.5 km al O de Las Mesilla por la carretera 200D rumbo a Las Varas, 15–20 km antes de llegar a esta población, 285 m, 21 November 2013 (fl, fr), J . G . González-Gallegos & A . Castro-Castro 1547 (holotype IBUG, isotypes CIIDIR, ENCB, IEB, MEXU, ZEA) .

Shrub 1–2.5 m tall, stems puberulent, with branched hairs, young branches reddish, scarcely aromatic. Leaves with petioles 1.7–3.1(–4) cm long, puberulent, densely covered with branched hairs; blade lanceolate, 6.2–14.5(–17) × (1.5–) 2.5–5.6 cm, acute to attenuate at the apex, rounded at the base and slightly oblique, margin serrate, both surfaces covered with branched hairs, mainly in the veins, and beneath. Inflorescence terminal, spiciform, lax to dense flowered, 18–40 cm long (sometimes the spiciform inflorescences branched and forming a raceme), cymes sessile (with no apparent peduncle), each node composed by a verticillaster with 30–40 flowers, floral bracts linear, 0.7–2.2(–4) mm long, bracteoles linear 0.8–1.2 mm long; inflorescence axes, floral bracts and pedicels covered with appressed hairs and sometimes with branch hairs as those in the stems and leaves; inflorescences become pendulous and flowers resupinate as the axis is overcome by the weight. Flowers with pedicels (6.7–) 9–15 mm long. Calyx tube 2–3.2 mm long and 1.8–2.1 mm wide at the throat in flower (up to 5–5.5 × 2.5–3 mm in fruit), calyx teeth 0.2–0.4 mm long in flower (up to 0.5 mm long in fruit), densely covered with pale purple branched hairs. Corolla dull violet to lavender, sparsely pilose at the apex including the lobes; tube (4.6–) 5.2–6.4 mm long, 1.5–2 mm wide at the throat, lobes subequal, 2–2.5(–2.9) mm long. Stamens 4, attached at 3.6–5.5 mm of corolla tube length; filament 1.7–2.5 mm, pilose; thecae 0.2–0.7 mm long. Style (8.7–) 10–11.6 mm long, long exserted, white and glabrous, without stylopodium, bifurcate at the apex, the branches acute. Mericarp 4, ovoid, triquetrous, 1.2–1.4 × 0.8–0.9 mm, black, tiny verrucose and glabrous.

Distribution, habitat and phenology:— Hyptis macvaughii inhabits in western Jalisco, in the municipality of Puerto Vallarta, and southern Nayarit, in the municipality of Compostela (figure 1). It grows in savannoid vegetation and ecotones of this with tropical subdeciduous forests, from 200–430(–1204) m elevation. It shares habitat with Alvaradoa amorphoides Liebm. , Barleria oenotheroides Dum. Cours. , Bejaria mexicana , Brosimum alicastrum Sw. , Bursera fagaroides (Kunth) Engl. var. elongata McVaugh & Rzed. , Byrsonima crassifolia (L.), Kunth, Chamaedora pochutlensis Liebm., Clethra rosei Britton , Cochlospermum vitifolium (Willd.) Spreng. , Cryosophila nana (Kunth) Blume ex Salomon , Curatella americana, Dioscorea sp., Erythroxylum havanense Jacq. , Glossostipula blepharophylla (Standl.) Lorence , Hyptis suaveolens (L.) Poit., Mandevilla subsagittata (Ruiz & Pav.) Woodson , Maranta arundinacea L., Miconia saxicola Brandegee , Pinus maximinoi , Quercus acutifolia Née , Q. aristata Hook. & Arn. , Tabebuia sp. , Vitex mollis Kunth , V. pyramidata B.L.Rob. , Waltheria lundelliana J.G.Saunders , Zamia sp. and several species of grasses. It flowers and fructifies from September to December and probably extending until March.

Etymology:— Hyptis macvaughii is dedicated in recognition to the efforts of Rogers McVaugh (1909–2009), an outstanding botanist who contributed greatly to the exploration and knowledge of western Mexican flora. This new name is one of many more coined to honor his contributions ( Carvajal & González-Villarreal 2012).

Taxonomic relationships:— Hyptis macvaughii can be easily distinguished from the members of section Umbellatae Epling (1949: 197) by means of its flowers directed attached to thicken portion of main floral axis instead of forming an umbel or panicle through the insertion of pedicels to a secondary floral axis (peduncle), together with its inconspicuous linear floral bracts and indumenta composed of branched hairs throughout stems, leaves, inflorescence axes, pedicels and calyces (figures 4 and 5). Hyptis subtilis Epling (1933b: 79) is its morphologically most similar species, but H. macvaughii can be separated from this because of the peculiarities already mentioned about the inflorescence without a peduncle and plant indumenta composed of branched hairs; the slightly shorter petioles [1.7–3.1(–4) vs. 2.7–6.1 cm], more flowers per floral node (30–40 vs. 15–21), longer pedicels (6.7–15 vs. 4–5.8 mm), slightly shorter calyx teeth in flower (0.2–0.4 vs. 0.5–0.6 mm in flower) and in fruit (up to 0.5 vs. 0.8 mm), longer corolla tube [(4.6–)5.2–6.4 vs. 2–2.7 mm), longer style [(8.7–)10–11.6 vs. 4.3– 4.9 mm), production per flower of 4 fertile mericarps instead of only 1 and these smaller (1.2–1.4 × 0.8–0.9 vs. 1.5– 2.1 × 1.4–1.6 mm), are other characters that supports the recognition of the former. The elevation range and type of vegetation both species occupy are not substantially different, both grow in tropical environments, though the distribution of H. macvaughii is much more restricted (figure 1, table 3).

Hyptis iodantha Epling (1939: 16) is the third representative of section Umbellatae in Mexico. The three species altogether constitute an interesting case of disjunction since the other species of this section grow in South America ( Argentina, Bolivia, Brazil, Colombia, Paraguay, Peru, and Uruguay) without any continuous connection between both areas of distribution ( Fernández-Alonso 2010). Finally, H. macvaughii would belong to the genus Condea according to the proposal of Harley & Pastore (2012).

Conservation assessment:— Hyptis macvaughii appears to be in danger of extinction, based on its limited geographic range. It should be classified as endangered [EN, criteria B1a] according to the IUCN (2008). Changes in land use are the greatest threat to this species.

Additional specimen examined (paratypes):— MEXICO. Jalisco. Puerto Vallarta: Ojo de Agua , 8.3 km en línea recta al SO de Llanitos, 1204 m, 28 November 2013, A . Flores-Argüelles & A . R . Romero 873 ( IBUG); cresta Palo María y Chupalodo, hacia el mirador de la cascada del río Mismaloya , 430 m, 30 November 2013, E . Iñarritu- Medina et al. s.n. (IBUG). Nayarit. Compostela : 5–6 miles W of Mazatán, 350 m, 17 September 1960 (fl), R . McVaugh 19093 ( MICH!); 8 km above ( E of) Las Varas, new road to Compostela , 200 m, 20 December 1970 (fl), R . McVaugh 25584 ( MICH!); 11 km by road E of Las Varas toward Compostela , 200 m, 28 October 1971 (fl), J . V .A. Dieterle 3933 ( MICH!); along highway 200, W of Compostela , 2.5 miles W Mesillas, 280 m, 9 October 1978 (fl), T . F . Daniel 1070 ( MICH!); 3.5 km al O de Las Mesillas por la carretera 200D rumbo a Las Varas , 15–20 km antes de llegar a esta población, 285 m, 15 August 2013 (fr), J . G . González-Gallegos & A . Castro-Castro 1536 ( IBUG!, IEB!, MEXU!, ZEA!) .

Figures

FIGURE 1. Distribution map of Hyptis pseudolantana (squares), H. cualensis (triangles), and H. macvaughii (dots) in Mexico.

FIGURE 4. Hyptis macvaughii holotype.

FIGURE 5. Hyptis macvaughii spiciform and racemose terminal inflorescences (A, C, E), stem (B), verticillaster, calyx and corolla detail (D), infructescence (F, G).