Hechtia huamelulaensis I. Ramírez & Carnevali, 2014

Morillo, Ivón Ramírez, Jiménez, Carlos F., Fernández-Concha, Germán Carnevali & Pinzón, Juan P., 2014, Three new species and growth patterns in Hechtia (Bromeliaceae: Hechtioideae), Phytotaxa 178 (2), pp. 113-127 : 119-122

Hechtia huamelulaensis I. Ramírez & Carnevali , spec. nov. ( Figs. 3 , 4 , Table 1).

A species similar to Hechtia glauca but leaves dull matte green (vs. glaucous), the leaf margins not undulate (vs. undulate throughout), without tufts of hairs in axils of spines (vs. with tuft of hairs in axils of spines); peduncle of the pistillate inflorescence 20–23 cm long (vs. 40–75.5 cm long); staminate sepals 2.5–3.4 mm long (vs. 1.6–2.2 mm long), pistillate floral bracts longer (2.4–4.7 mm vs. 1–2.3 mm long); fruits ellipsoid, not pendulous, 9–12.3 x 4.5–5.7 mm (vs. ovoid, pendulous, (8)9–12 x 3.5–5 mm).

TYPE:— MEXICO. Oaxaca: Municipio San Pedro Huamelula, desvío de la Carretera Federal 200 a San Pedro Huamelula, ca. 1 km, desde la carretera Salina Cruz a Pochutla , [deviation from federal road 200 to San Pedro Huamelula, ca. 1 km, from the road from Salina Cruz to Pochutla], 15° 59’ 44” N, 95º 39’ 57” W, 62 m elevation, originally collected in March 2011, blooming under cultivation, 2 Marzo 2013, Ramírez & Carnevali 1675c ♀ (holotype, CICY (x2)!) .

Plants lithophytic, rosettes globular, 50–60 cm in diameter, 25–30 cm tall. Leaves 30–40 in number, reflexed; sheaths transversely oblong, 7–8 x 10–12 cm, entire, yellowish green, glabrous, with flat or undulate margins only at base; blades narrowly triangular, long acuminate, 30–35 x 6–8 cm, recurved, succulent, broadly and shallowly channeled in cross section, dull mat green, occasionally the apical portion reddish, glabrous and opaque adaxially, white lepidote abaxially, margins straight, sometimes basally undulate, armed, red; spines antrorse, 3–5 mm long, 1–1.5 cm apart, red. Inflorescence central, emerging from lateral young rosettes (type SPFP), erect.

Staminate inflorescence (only known from dry specimens and pictures in habitat) an once-branched panicle, pyramidal, erect, 60–80 cm long; peduncle terete, ca. 20 cm long, 0.5–0.8 cm in diameter at the base, as long as the height of the rosette or shorter, internodes 1–1.5 cm long; peduncle bracts with broadly triangular sheaths, appressed to the peduncle, 2–3 x 4–7 mm, margins thin, narrowing abruptly into the blade; the blade narrowly triangular, long acuminate, 2–10 x 0.5–0.7 cm, entire to finely serrate, light brown, sparsely white-lepidote at the apex, multinerved; main axis 40–50 cm long, 0.5–0.6 cm in diameter at the base, upward to ca. 2 mm in diameter, dark olive green, internodes 1.5–3 cm long; primary bracts triangular, acuminate, 0.7–2 x 0.3–0.8 cm, margins entire and very thin, light brown, glabrous, multinerved, shorter than the branches; branches 47–53 in number, forming an angle of 90° or nearly so with the main axis, 2.5–13.2 cm long, with (8–)11–38 flowers, the distal flowers often not developing, color unknown; rachis ca. 1 mm in diameter, flattened at its base, then sulcate, drying light brown, glabrous, sterile basal portion 0.3–0.8 cm long, naked; floral bracts broadly ovate, acuminate, 2.3–2.6 x 2 mm, margins erose, minutely serrate at the apex, shorter than the sepals, glabrous, 5-nerved. Flowers (unknown at anthesis in vivo) shortly pedicellate, erect; pedicels obconic, ca. 1 mm long, ca. 0.5 mm in diameter, glabrous; sepals ovate to triangular-ovate, acute, 2.5–3.4 mm x 1.3–2 mm, erose, glabrous, 7-nerved, shorter than the petals; petals elliptic, rounded, 4.5–6.1 x 2.5–2.8 cm, entire, 7–9 nerved; filaments narrowly triangular, 4–4.7 x 0.7–1 mm; anthers oblong, 1.6–1.9 mm long; pistillode ovoid, reduced, 1–1.3 x 1.2–1.4 mm, stigmatic lobes 0.2–0.4 mm long.

Pistillate inflorescence (known from live material) a once-branched panicle, pyramidal, erect, rigid, 92–112(– 121) cm long; peduncle terete, 20–23 cm long, 1.1–1.3 cm in diameter at the base, as long as the height of the rosette or slightly longer, internodes 1–1.5 cm long, olive green to purple; peduncle bracts with broadly triangular sheaths, these appressed to the peduncle, 3–5 x 5–9 mm, serrulate, narrowing abruptly into the spreading blades; the blade narrowly triangular, long acuminate, 2.2–12 x 0.7–1 cm, entire, light brown with some pinkish hue, base and apex reddish, sparsely white lepidote mainly at the apical abaxial surface, multinerved; main axis 70–98 cm long, 0.7–1.1 cm in diameter at the base, upward to ca. 2 mm in diameter, internodes 1–1.5 cm long; primary bracts triangular, acuminate, 0.7–2.8 x. 0.3–0.7 cm, margins entire and very thin, light brown, glabrous, multinerved, much shorter than the branches except the lower ones equaling the shorter branches; branches 46−94 in number, forming an angle of ca. 90° or nearly so with the main axis, 1.5–13 cm long, with 4−40 flowers, the apex bearing abortive flowers; rachis 0.3–1(–3) cm long, ca. 0.2 cm in diameter, naked, dorsiventrally flattened at the base, then sulcate, dark purple, without sterile portion at its base; floral bracts variable in shape and size, oblong to triangular, acuminate, 2.4–4.7 x 1.5–2.8 mm, erose, with some scattered tiny spines at the apex, scarious, basally green, apically brown, glabrous, 8–9 nerved, as long as or longer than the pedicel. Flowers pedicellate, erect; pedicel terete, 1.5–3 mm long, ca. 1 mm in diameter, glabrous; sepals variable in size, deltoid, acute, 1.3–2.6 x 2–2.5 mm, entire to erose, purple, glabrous, 5–7-nerved, appressed to the petals; petals ovate, acute, 4–5.2 x 2–2.7 mm, ca. 7-nerved, arranged so as to form a star-like corolla, white, basally green, with a red longitudinal stripe, often with the red color spreading over the whole surface; staminodes narrowly triangular, 2.7–3.3 x 0.5–0.8 mm, sometimes apically capitate; ovary oblongoid to ovoid, 3.2–3.5 mm long, 1.8–2.3 mm in diameter, light green, apex purple, stigmatic lobes recurved, 1–1.2 mm long, light purple. Fruits narrowly ellipsoid, 9–12.3 mm long, 4.5–5.7 mm in diameter, glabrous, pendulous; pedicel stout, ca. 2 mm long, 1 mm in diameter, the sepals, petals, and staminodes persistent; seeds fusiform, (4–) 6.3–8.4 mm long, (0.5–) 0.7–1.1 mm in diameter, apical wing 0.4–0.6 mm long, basal wing (2–) 3–3.9 mm long.

Distribution:— Hechtia huamelulaensis occurs in the southeastern area of the State of Oaxaca ( Fig. 3 ), on the Pacific slopes of the Tehuantepec Isthmus, an area belonging to the Costas del Sur Physiogeographical Province ( Cervantes-Zamora et al., 1990). So far it is only known from the vicinity of the village of San Pedro Huamelula in the municipality of the same name. The area where this species has been found coincides with a relatively small patch of hot arid climate (type BSo(h’)w), which is embedded within a more extensive region of tropical subhumid climate ( García 1998 ). At this single locality, H. huamelulaensis grows in xerophytic vegetation at an elevation of ca. 60 m and is associated with such other plants as Agave ghiesbreghtii Lemaire ex Jacobi (1864:545) , Plumeria rubra Linnaeus (1753: 209) , Opuntia decumbens Salm-Reifferscheid-Dyck (1834: 361), and a laxly-flowered form of Hechtia rosea .

Etymology:— The epithet refers to the locality where the new species was collected, San Pedro Huamelula in Oaxaca, Mexico.

Additional specimen examined (paratypes):— MEXICO. Oaxaca: Municipio San Pedro Huamelula, desvío de la carretera federal 200 a San Pedro Huamelula, ca. 1 km, desde la carretera de Salina Cruz a Pochutla, 15° 59’ 44” N, 95º 39’ 57” W, 62 m elevation, 25 March 2011, Ramírez & Carnevali 1675a ♂ (CICY!), 1675b fruits (CICY!, MEXU!, OAX!, US!), same locality, flowering on cultivation, 01 March 2013, Ramírez & Carnevali 1882 ♀ (MEXU!, US!).

Discussion:— Hechtia huamelulaensis is characterized by the following combination of characters: rosettes with broad, succulent leaves, these dull mat green, often reddish at apex and margins, and white lepidote abaxially; the inflorescences are central but emerging from a young, newly formed lateral shoot (type SPFP); the main axis of the pistillate inflorescences as well as the sepals are dark purple, the pistillate flowers have white petals, sometimes with a purple longitudinal mid line abaxially, and pink stigma lobes.

Actually, there are some other populations of Hechtia in the same phytogeographical region of the Tehuantepec Isthmus where H. huamelulaensis grows that share the same rosette architecture with some variations on leaf number, width and length, cross section and color, but with different floral and fruit features that allow differentiating them from the new species. These are referable to species such as H. fosteriana L. B. Sm. (1961:8) and H. rubicunda Espejo & López-Ferr. in López-Ferrari & Espejo (2014:154), and perhaps others yet to be formally recognized. Because the taxonomy of this group of taxa is unresolved at this time and no closest relative to our new species is obvious, we have chosen to compare our new species against an unrelated taxon that is, however, vegetatively similar. Thus, we contrast the new species with H. glauca Burt-Utley & Utley (1993: 220) ( Table 1), native of the Mexican state of Michoacán, which is similar in rosette features.

Hechtia huamelulaensis differs from H. glauca by its dull matte green leaves (vs. glaucous), blades with flat or undulate margins only at base (vs. undulate throughout), leaf surfaces densely lepidote abaxially, without tufts of hairs in axils of spines (vs. glabrous with tuft of hairs in axils on spines), peduncle of the pistillate inflorescence 20–23 cm long (vs. 40–75.5 cm long), staminate sepals 2.5–3.4 mm long (vs. 1.6–2.2 mm long), pistillate floral bracts longer (2.4–4.7 mm vs. 1–2.3 mm long); fruits ellipsoid, not pendulous, 9–12.3 x 4.5–5.7 mm (vs. ovoid, pendulous, (8)9–12 x 3.5–5 mm).

IUCN Conservation assessment: Vulnerable (VU). Hechtia huamelulaensis meets criteria D2 of the IUCN (2010). The species is known from an area of less than 2 km 2 within which it occurs only at a handful of small sites. Albeit local populations of the species can be rich in individuals and are often inaccessible, they are widely scattered and isolated on the slopes and tops of small rocky hills.

Figures

FIGURE 3. Geographical distribution of the three new species: Hechtia flexilifolia, H. huamelulaensis, and H. nivea.

FIGURE 4. Hechtia huamelulaensis (A, C–F). A. Rosette (plant in cultivation). C. Plants in habitat, note the brown, erect infructescence. D. Pistillate inflorescence. E. Details of pistillate flowers, note the purple color on the floral parts. F. Different morph of pistillate flowers, patent and lighter petals. B. Hechtia glauca, its rosette resembles that of H. huamelulaensis (Photographs:A, B, D. Ivón Ramírez; C. Juan Pinzón, E–F. Débora Carnevali).