Hechtia marthae I. Ramírez, 2021

Ramírez-Morillo, Ivón, Carrillo-Reyes, Pablo, Tapia-Muñoz, José Luis & Ramírez-Díaz, Claudia J., 2021, In disentangling two species limits of Hechtia (Bromeliaceae: Hechtioideae) from Sierra Madre Occidental, a new species is discovered from Durango, Mexico, Phytotaxa 523 (1), pp. 55-72 : 63-67

Hechtia marthae I. Ramírez , sp. nov. ( Figures 4 , 5 ).

TYPE:— MEXICO: Durango: Municipio Nombre de Dios, adelante de Nombre de Dios, camino a El Venado , 11 km del desvío, matorral de encino-pino, sobre laderas en suelo volcánico, 23°47’55’’N, 104°17’40’’W, 1745 m, originally collected by I. Ramírez, A. Espejo, A. López-Ferrari, A. Mendoza & J. Ceja, September 2005, flowering under cultivation, June 2009, I. Ramírez & G. Carnevali 1627 ♂ (Holotype, CICY!) .

Diagnosis: — Hechtia marthae is similar to H. subalata but differs in its pistillate branches much shorter than the primary bracts (vs. conspicuously larger than the primary bract), with shorter branches (2–5 vs. (2–) 5–15 cm long), floral bracts narrowly triangular, 2–5 × 1 mm (vs. broadly ovate, 3–4.5 × 3–4 mm), ovary 1/3 inferior (vs. completely superior), with longer petals (5–7 vs. 3–5 cm long).

Plants lithophytic or terrestrial, cespitose, 1.1–1.75 m height when flowering; rosettes generally round, 30–40 cm tall, 35–45 cm in diameter, generally forming dense, colonies of 5–21 rosettes. Leaves 20–30 in number, central ones erect to slightly reflexed in basal ones; sheath ovate to broadly ovate, 2.8–6.5 × 2–6.3 cm, light brown, margins entire and erose distally, lustrous and glabrous at the base, slightly lepidote distally; blade narrowly triangular, acuminate to long attenuate, 20–33(–50) × 1.3–4 cm, green, reddish toward the apex and margin when sun exposed, densely white lepidote abaxially, white lepidote adaxially; marginal spines antrorse and retrorse, triangular, 2–5 mm long, 6–20 mm apart, brown, with a short tuff of white trichomes in the concave portion of the spine. Inflorescence central, erect, emerging from a mature rosette (strict sympodium growth pattern, type SPP sensu Ramírez-Morillo et al. 2014).

Staminate inflorescences a once-divided panicle, cylindrical in general shape, erect, 0.7–1.35 m long; peduncle terete, green to light brown, slightly white lepidote, 33–79 cm long, 8–17 mm in diameter at the base, longer than the rosette; internodes 0.8–2.5 cm long; peduncle bracts the basal ones, with ovate sheath, 2–3 × 1.5–2 cm, the blades narrow triangular, 9–24 × 0.9–1.3 cm, the distal bracts with a sheath rectangular to triangular, 4–7 × 0.8–1.4 cm, margins entire then erose and spiny toward the blade, this long attenuate to acuminate, multi-nerved, brownish, densely white lepidote abaxially, glabrate or slightly lepidote adaxially, longer than internodes, clasping the peduncle; rachis (main axis) 33–62 cm long, 3–9 mm in diameter at the base, terete, green to brownish; internodes 0.8–3.6 cm long, white lepidote; primary bracts rectangular to triangular, abruptly acuminate, 4–5 × 1.2–1.4 cm, entire at the base to erose and spiny toward the apex, brown when dry, sparsely white-lepidote abaxially, glabrous to slightly lepidote adaxially, multi-nerved, about the length of the branches; branches 18–27 in number, forming an angle of 15° or less with the rachis, (1.8–) 4–7.5 cm long, ca. 5 mm in diameter, 16–29 flowered; rachis (branch) flattened at its base, 0.2–1 cm long, glabrous, stipe; floral bracts inconspicuous, narrowly-triangular, acuminate, 1.5–2(–4) × 0.1 mm, green, brownish at the apex, slightly lepidote, inconspicuously nerved, equaling or slightly exceeding the pedicel. Flowers pedicellate, polystichous, 7–9 mm long, 3–5 mm in diameter, fragrant during the morning (sweet smell); pedicel obconic, 2–3 (–4) mm long, ca. 1 mm in diameter, light green, slightly lepidote; sepals ovate to triangular, acute, 3–4 × 1.8–3 mm, entire, green at the base, apically brownish, slightly lepidote at the base, 3-nerved, shorter than petals; petals elliptic, acute, 5–6 × 2–3.5 mm, green with brownish spots, multi-nerved; filaments triangular, terete, 4–5 mm long, ca. 1 mm in diameter, white to greenish; anthers oblong, 2–3 mm long, dorsifixed, green, pollen yellow; pistillode reduced, 0.5–0.8 mm long × 1.5 mm in diameter, light green, stigmatic lobes much reduced.

Pistillate inflorescences a once-divided panicle, in general shape cylindrical, erect, 0.83–1.12 m long; peduncle terete, 40–55 cm long, 0.8–1.9 cm in diameter at the base, longer than the rosette; internodes 1–2.5 cm long; peduncle bracts without clear distinction between sheath and blade, basal ones with ovate sheath, blade triangular and long acuminate, 5–8.5 × 1.8–2.6 cm, margins entire at the base to erose and spiny distally, brownish, densely white lepidote abaxially, glabrate or slightly lepidote adaxially, multi-nerved; longer than internodes, clasping the peduncle; rachis (main axis) 30–57 cm long, ca. 0.7–1.1 cm in diameter at the base, terete, green, internodes 1–3 cm long; primary bracts rectangular to ovate-triangular, acuminate, 2–4 × 0.8–2 cm, brown when dry, sparsely white-lepidote abaxially, glabrous to slightly lepidote adaxially, entire at the base to erose and spiny toward the apex, multi-nerved, as long or shorter than the branches; branches 15–25 in number, in an angle of ca. 45° with the rachis, 2–5 cm long, ca. 1.3–1.8 cm in diameter (up to 4 cm when in fruit) 5 mm in diameter, 10–20 flowered; rachis (branch) terete, white lepidote, glabrous in the infructescence, stipe nearly none; floral bracts inconspicuous, narrowly-triangular, acuminate, 2–5 × 1 mm, green, white lepidote, margins serrate. Flowers pedicellate, verticillate, fragrant during the morning (sweet smell), 10–12 mm long, ca. 5–7 mm in diameter; pedicels which are a constriction of the base of the floral receptacle resembling a pedicel, obconic, 2–3 mm long, 1–2 mm in diameter, tomentose; sepals ovate to triangular, acute, 4–5 × 3–4 mm, green, slightly lepidote abaxially, entire, 3-nerved; petals elliptic, acute, 5–7 × 3–4 mm, green, glabrous, entire, multi-nerved; staminodes six in number, narrowly triangular, laminar, 2.5–2.9 mm long, ca. 1 mm at the base; ovary 1/3 inferior, oblongoid, 7–9 mm long, 3–4 mm in diameter, glabrous, green, stigmatic lobes recurved, ca. 1 mm long, pale green. Fruits pedicellate (rather the base of the floral receptacle shrinks and resembles a pedicel), ellipsoid, 10–14 mm long, 5–8 mm in diameter, glabrous, green when mature, brown when dry; seeds fusiform, 3.5–5 mm long, 1–1.5 mm in diameter, brown, reticulate, caudate, wings ca. 1 mm long, brownish.

Additional specimens examined:— MEXICO. Durango: Municipio Mezquital, Temoaya , a 4.5 km por el camino a Agua Zarca , 23°20’N, 104°30’W, matorral subtropical, 1650 m, August 18, 1983, M. González E. s.n. fruits ( CIIDIR!, HUAA!, UAMIZ!, UJAT!); Temoaya, 2.5 km al noreste por la carretera a Mezquital , 23°18’59’’N, 104°29’19’’W, matorral subtropical, 1704 m, May 25, 2020 (cultivated), R. Quirino-Olvera 143♀ ( CICY!); Municipio Nombre de Dios, Chachacuaxtle , 33 km al SSW de Nombre de Dios, 22°40’N, 104°16’W, matorral subtropical, 1740 m, March 21, 1988, S. González E. 4086 fruits ( CIIDIR!, HUAA!, UAMIZ!, UJAT!); ca. 10 km sobre la brecha a El Venado , a partir de la carretera Nombre de Dios-Durango , 23°47’55’’N, 104°17’40’’W, matorral espinoso, 1739 m, July 25, 2003, A.R. López-Ferrari et al. 2989 fruits ( UAMIZ!, UJAT!); 2993♂ ( UAMIZ!, UJAT!); ca. 10 km en la brecha que va de la carretera Durango-Nombre de Dios hacia El Venado, 23°47’54.3’’N, 104°17’38.8’’W, cañada con matorral xerófilo, 1751 m, June 18, 2009, I. Ramírez 1627♂ ( CICY!, WU!); same locality, June 3, 2013, I. Ramírez 2205♂ ( CICY!); same locality, October 31, 2019, I. Ramírez et al. 2442 fruits ( CICY!); Municipio Topia, canyon below Topia, just downstream from Los Molinos , on cliff, 3800 feet alt., June 1978, M. Kimnach & H. Sánchez-Mejorada 1777♂ ( HNT!, US!) .

Phenology:—Staminate plants have been collected in June, pistillate plants only reported for May, while fruiting specimens have been collected from March to October.

Distribution and habitat: —Populations of Hechtia marthae has been found thus far only on four localities in the western slope of the Sierra Madre Occidental, in the state of Durango, in Mezquital, Nombre de Dios, and Topia municipalities. Its distribution matches partially with the extensions of the Pacific Lowlands province that penetrate the lowlands of the Sierra Madre Occidental province ( Morrone et al. 2017). It grows at elevation between 1158–1751 m, on xerophytic shrublands and subtropical scrub along with species of Agave L., Dasylirion Zucc. , Fouquieria Kunth , Opuntia , Prosopis L., and Vachellia Wight & Arn. ( Figure 5 ).

Eponomy:—The species is named after Martha González-Elizondo in recognition for her outstanding contribution to the knowledge on the Flora of Durango and for collecting material of the species.

IUCN Conservation assessment:—The GeoCAT ( Bachman et al. 2011) indicates that, based upon the EOO (7953 km 2) and AOO (28 km 2), H. marthae is classified as Vulnerable (VU) and Endangered (EN), respectively, according to the IUCN B set of criteria. In order to better understand the conservation status of this species robustly, it is necessary to evaluate demographic aspects of its populations and possible threats.

Discussion: —Populations included here in Hechtia marthae were misidentified previously as Hechtia subalata or H. podantha Mez (1896: 549) , due to a holotype that only represents an apical portion of an immature infructescence (see Table 1 for comparisons of main differences among the three species). As many species of Hechtia , blooming periods are very short and flowers in an inflorescence are open for 1–3 days, making difficult to document floral structures which show more accurately differences among species (such as colors, shapes, fragrances, etc.). This species shows wide and relatively long primary bracts, lepidote, with condense pistillate branches resembling species of the Hechtia podantha complex ( Martínez-Correa 2008), probably a case of convergent evolution grouping species from different lineages ( Ramírez-Morillo et al. 2018a) invading high elevation dry habitats occasionally exposed to frosts.

Hechtia marthae , H. podantha and H. subalata are very similar in several features: they share the central inflorescence that emerges from a fully formed rosette, inflorescences in both sexes have their primary branches subtended by a conspicuous primary bract, branches are usually condensed, and flowers are usually green, as well as the fact that inflorescences are in bloom for 2–3 days, a common feature of Hechtioideae but with few exceptions. Main differences among the three species are depicted on Table 1 .

Figures

FIGURE 4. Hechtia marthae. A. Pistillate plant in bloom. B. Staminate plant in bloom. C. Detail of inflorescence with young fruits. D. Female flowers at anthesis.E. Male flowers at anthesis. Illustration byAlberto Guerra based on photographs byA, D. Ricardo Quirino-Olvera. B. Gustavo Romero-González. C.Adolfo Espejo-Serna from the specimen A. R. López-Ferrari et al. 2989 (UAMIZ). E and staminate rosette based of photographs by Ivón Ramírez-Morillo. D and pistillate rosette in based of photographs by Ricardo Quirino-Olvera.

FIGURE 5. Hechtia marthae. A. Plants in habitat. B. Infructescence with open fruits in habitat. C. Seeds. (Credits A-C. Ivón Ramírez- Morillo).

Tables

TABLE 1. Main differences among Hechtia marthae, H. podantha and H. subalata. *Characters for Hechtia podantha were mostly taken from Espejo-Serna et al. (2010) and completed with information from herbarium specimens; seed features were from Fatzer (1996) and Gorocica (2017).

Characters	Hechtia marthae	Hechtia podantha *	Hechtia subalata
Leaf blades: length x	20–33(–50) × 1.3–4	19–44.7 × 0.5–1.5	20–50 × 2.5–4.8
width (cm)
Leaf blade surfaces	Densely white lepidote	Minutely white lepidote adaxially,	Densely white lepidote abaxially,
	abaxially, white lepidote	rather glaucous, white lepidote	white lepidote at base but soon
	adaxially; rarely developing a	abaxially; rarely developing red	glabrous and glossy adaxially;
	red color on the blade	longitudinal lines at the margin of	sometimes developing a red spot at
		the blades	the base of the spine
Spines length (mm);	2–5; 6–20 apart, with white	3.1–7 (–8); 6.4–32 apart	1.5–2.5; 8–25 apart
separation	tuff of hairs on concave portion
	of spine
♂Inflorescence type	1-branched	3-branched	1–branched
♂Peduncle diameter	8–17; green to light brown,	4.6–11(–15), dark green to purple,	5–14; green to brownish, densely
mm; color; surface	slightly white lepidote	sparsely white lepidote	white lepidote
♂Primary bracts length	40–50 × 12–14; rectangular	22–48(–60) × 7–12(–25); widely	12–40 × 8–14; narrowly ovate-triangular
and width (mm); shape	to triangular and abruptly	ovate
	acuminate
♂Branch length (cm)	(1.8–)4–7.5	1.6–6.6	2.5–10(–15)
♂Floral bracts (mm);	2–4 × 1; linear-triangular,	1.2–3.1 × 0.2–1; linear to triangular,	4.5–6 × 2.5–4.5; broadly ovate,
shape	acuminate	acute	acute
♂Pedicels length (mm)	2–3(–4)	1.4–2.7	0 (sessile flowers)
♀Inflorescence length	Once-branched; 83–112	3-branched, 35–127	Once-branched; 120–170
(cm)
♀Peduncle diameter	8–19; light green; densely	7.3–18; dark green to purple;	8–20 mm; green to brownish;
mm; color; surface	white lepidote	sparsely white lepidote	sparsely lepidote
♀Branch length (cm)	2–5	2.5–9	(2–)5–15
♀Primary bracts (mm)	20–40 × 8–20; rectangular to	24–60 ×18–20; ovate triangular	15–25 × 8–15; triangular
	ovate triangular
♀Floral bracts (mm)	2–5 × 1; narrowly triangular,	1.1–5.3 × 0.1–0.6; triangular, acute	3–4.5 × 3–4, broadly-ovate, acute
	acuminate
Fruit length; diameter	10–14; 5–8, ellipsoid	7.1–12; 4.1–6.5, ovoid	9–15; 6–7; ellipsoid
(mm), shape
Seeds length x diameter	3.5–5 × 1–1.5; fusiform	2–52; 7.2–21; ellipsoid	35–40 × 1; triangular
(mm); shape
Distribution (Mexican	Durango	Hidalgo, Aguascalientes,	Durango, Jalisco, Nayarit, Zacatecas
States)		Guanajuato, Querétaro

mostly taken from Espejo-Serna et al. (2010) and completed with information from herbarium specimens; seed features were from Fatzer (1996) and Gorocica (2017).