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Hechtioideae Givnish, a Megamexican lineage (distributed in Megamexico III sensuRzedowski 1991), contains three genera: Bakerantha L.B.Sm. restricted to Mexico, Mesoamerantha I.Ramírez & K.J.Romero distributed in Belize, Guatemala, Honduras, El Salvador, and Nicaragua (Romero-Soler et al. 2022a, b); and Hechtia Klotzsch, with the largest amount of its species in Mexico, few ranging into United States to the north, and in Belize, Guatemala, and Honduras to the south.
All Hechtia taxa are dioecious (but one polygamomonoecious, Hechtia gayorum L.W. Lenz). Most species have individuals with large to medium-sized rosettes and long inflorescences, making difficult to prepare herbarium specimens that adequately represent all forms and dimensions of the species, resulting in fragmentary vouchers: a leaf, and one or few branches of the inflorescences of one sex. The locality also is vague for several species, making impossible to relocate them, this is very important because of the narrow endemicity of almost all species (Rivera-Martínez et al. 2022). An additional factor that makes species identification difficult is the floral dimorphism, i.e., the differences between flowers of both sexes is not only the presence/absence of anthers and pistil but floral size, color, arrangement on the inflorescence, etc. About 70 Hechtia species were described before 1994 but since 2007, 46 species have been described, becoming the Mexican genus with the largest rate of species description in the family. Fortunately, species described since 2007 are well morphologically and geographically documented, with images of plants in habitat and cultivation, providing all information to understand the species (e.g. Flores-Argüelles et al. 2019, Hernández-Cárdenas et al. 2022, Ramírez-Morillo et al. 2023a; for the complete list go to https://www.tropicos.org/name/Search?name=hechtia).
Within the 15 provinces proposed by Morrone et al. (2014) in Megamexico, for the genus Hechtia, the Balsas Basin is the one with the largest number of species (36) and endemism (22), followed by the Pacific Lowlands (25 species, 12 endemic) and Sierra Madre del Sur (24 species, 10 endemic) (modified from Rivera-Martínez et al. 2022), figures subject to change by new species described every year for the genus, which reaches more than 90 species. For the Mexican state of Jalisco, there are seven reported species of Hechtia (McVaugh 1989, Espejo-Serna & López-Ferrari 2018, Flores-Argüelles et al. 2019, Ramírez-Morillo et al. 2023b), which are: H. iltisii Burt-Utley & Utley, H. jaliscana L.B.Smith, H. pedicellata S.Watson, H. santanae I.Ramírez & P.Carrillo, H. subalata L.B.Sm. (but also present in the neighboring states of Zacatecas and Nayarit, Ramírez-Morillo et al. 2021), H. ibugana Flores-Arg., Espejo & López-Ferr.; and the recently described H. carrilloi I.Ramírez (Ramírez-Morillo et al. 2023b). All of them are endemic to Jalisco excepting H. subalata. The presence of Hechtia podantha Mez in Jalisco (McVaugh 1989) has been previously discussed (Ramírez-Morillo et al. 2016, 2023b) and its presence in Jalisco has not confirmed. The new species herein proposed will be the eighth species reported to Jalisco, and the seventh endemic to this state.
Materials and methods
Field work was carried out under the scientific permits (SGPA/DGVS/01280/21 and SGPA/DGGFS/712/2913/17) issued by the Secretaría de Medio Ambiente y Recursos Naturales (SEMARNAT) to researchers at Centro de Investigación Científica de Yucatán, A.C. (CICY). To describe the new species, field work was performed in the Chamela-Cuixmala Biosphere Reserve, at Jalisco state where plants of both sexes were collected and herbarium specimens prepared, as well as bloomed under cultivation at the Roger Orellana Regional Botanical Garden at CICY (accession number 2021-012) in order to obtain fresh flowers of both sexes. The herbarium specimens were deposited at herbarium CICY (acronyms according to Thiers [count. updated]) whereas duplicates were sent to the herbarium IBUG. Specimens from herbaria MEXU, SLPM, and XAL were borrowed and studied as well. Additionally, we visited and studied collections at the following herbaria: GUADA, IBUG, MEXU (at UNAM and at the Chamela Biological Station), and ZEA. The new species was compared with all species reported for the Mexican state of Jalisco and surrounding states (Aguascalientes, Colima, Michoacán, Nayarit, and Zacatecas) and to those from the Pacific Lowlands, in order to determine its status.
Herbarium specimens of the new species from Chamela proposed here have been misidentified as Hechtia laevis L. B. Sm. and H. reticulata L. B. Sm., as a consequence of the fragmentary types of both taxa that do not allow to understand either of the two species morphology. We studied the types of both species and compare them with the specimens of the new species from Chamela. For H. reticulata, we studied the following types: Palmer 1352, HT: GH!, IT: US!; and for H. laevis: McVaugh 15528, HT: MICH!, IT: MICH!, in order to discard if the proposed new taxon was one of these two. All types of both taxa are fruiting specimens thus we compared pistillate inflorescence architecture, fruit shape and arrangement on the rachis, as well as seeds among them, resulting that the new species was neither H. reticulata nor H. laevis but a new to science taxon. Later, we provide information and detailed discussion to support our hypothesis.
Results
Hechtia chamelensis Magaña & I. Ramírez, sp. nov. (Figures. 1-4).
Figure 1 Hechtia chamelensis; A) Infructescence, note its length of the infructescence when growing on shady places, Dr. Pablo Carrillo-Reyes (right) and Dr. William Cetzal (left) on the picture; B) same species with shorter infructescence (pointed by an arrow) when growing on exposed places, this individual is a few meters from the previous one; C) details of the origin of the inflorescence (terminal or central); D) details of adaxial surface of the leaves, color of foliar blade and spines. Photographs: I. Ramírez-Morillo.
Figure 2 Hechtia chamelensis; A) pistillate inflorescence; B) a branch with pistillate flowers in anthesis; C) staminate inflorescence; D) a branch with staminate flowers; E) a comparison of staminate and pistillate flowers. Photographs: A-B and E: I. Ramírez, C: G. Carnevali, D: C. Ramírez-Díaz.
Figure 3 Hechtia chamelensis in bloom; A) staminate inflorescence; B) staminate flowers; C) pistillate inflorescence; D) pistillate flower; E) fruits. Illustration by Alberto Guerra based on photographs provided by Ivón M. Ramírez-Morillo.
Figure 4 Distribution of Hechtia chamelensis in Jalisco state, Mexico; A) location of the study area in the west coast of Mexico (orange square); B) collections of H. chamelensis inside the protected natural area Chamela-Cuixmala Biosphere Reserve (white circles), the yellow line indicates the boundaries of the reserve; C) close up of the collection locations of this species.
Type: Mexico. Jalisco, municipio La Huerta, estación biológica de Chamela, vereda Calandria, 350 m, 4 septiembre 1985, P. Magaña-Rueda & R. S. Almeida 317 (fruits, ♀MEXU-420881(1/6)!; ♂, fruits (MEXU-420882 (2/6)!; ♂MEXU- 660589 (3/6)!; ♂MEXU-666157(4/6)!; ♀MEXU-666159(5/6)!; ♂MEXU-676801(6/6)!).
Diagnosis. This new species differs from Hechtia reticulata in the following characters: fruits 5-6 per each 5 cm length (vs. 8-2 fruits), reticulate (vs. smooth), seeds ca. 1 mm long (vs. 3 mm), inflorescence branches 10-15 cm long vs. 10-12(-25) cm long). H. laevis has branches with many fruits (40-50 in each 5 cm length) while H. chamelensis only has 5-6 fruits in each 5 cm length, primary inflorescence branches have no stipe nor primary bracts (vs. 2.5-4 cm long in H. chamelensis and primary bracts triangular, long-acuminate, 3-4.5 cm long, 4-10 mm wide, longer to equaling the length of the stipe). The new taxon also shows staminate flowers 6-8 mm long, 7-9 mm diameter, petals apically white, basally pink, widely spread; pistillate flowers 3 mm long, ca. 1 mm diameter; with white petals and sepals basally green apically brown, adnate to the ovary.
Description. Terrestrial or lithophytic plants, rosettes cespitose, in general shape globose, 40-60 cm tall, 50-60 cm diameter, generally forming dense, small groups of 3-6 rosettes. Rhizomes abbreviated, 3-5 cm long. Leaves 40-60, rigid, central ones erect, basal ones slightly reflexed; sheaths broadly ovate, 4-6 × 4-5 cm, light brown, margins erose, densely white lepidote abaxially, lustrous and glabrous adaxially; blades narrowly triangular, attenuate, 26-40(-58) × 1-3(-4) cm, succulent, barely conduplicate in cross section, green, sometimes with red spots at the apex or margins, densely white lepidote abaxially, white lepidote at base but glabrous and glossy adaxially, margin straight, armed; spines antrorse, triangular, 1.5-2.5 (-5) mm long, 0.4-1(-1.5) cm apart, light green or occasionally purple, with a short tuff of white trichomes at the axile of the basal spines. Inflorescence central, erect, emerging from an immature or mature rosette (strict sympodial growth pattern, type SPP, sensuRamírez-Morillo et al. 2014).
Staminate inflorescence a 1 (-2)-divided panicle, cylindrical in general shape, erect, but becoming somewhat arched when in bloom, 1-1.25 m long; peduncle terete, 40-53 cm long, 0.9 cm diameter at the base, green, surface white-lepidote, internodes 1.5-2.5 cm long; peduncle bracts sheath wide triangular, 8-10 × 6-8 mm, purple, finely dentate, glabrous above, sparsely lepidote below, blade triangular, long attenuate, acute, 1.9-3.2 (-6 the basal ones) × 0.5-0.9 (-1.3) cm, brownish, entire to slightly erose, multinerved, homogeneously lepidote on the adaxial surface, abaxially glabrous, shorter than internodes but the very basal ones larger than internodes; rachis 60-75 cm long, ca. 4 mm diameter at the base until 1 mm in diameter at the apex, terete, green, slightly lepidote, internodes (2-) 2.5-3.5 cm long; primary bracts triangular, acute, (0.6-)1.4-1.9(-3.0) × 0.3-0.5 cm, papyraceous, shorter than the stipe of the branch, erose to spinulose, brownish, multinerved, lepidote adaxially, glabrous to slightly pustulate abaxially; branches 20 in number, forming an angle of 70-110° relative to the main axis, (3.5-)10-15 cm long, each with (13-) 30-40 flowers; stipe of the branch 1.4-4 cm long, 2.5 mm diameter at the base, terete; branch rachis 1 mm diameter, terete; floral bracts oblong to oblong-ovate, attenuate and acuminate, 2.3-2.7 × 1.5-1.8 mm, brown with some reddish macules at the base, abaxially and adaxially glabrous, margin erose and hyaline, ca. 5-10 nerved, almost as long than sepals at anthesis. Flowers subsessile, slightly fragrant with a sweet aroma, erect, 6-8 mm long, 7-9 mm diameter, actinomorphic, alternate or verticillate; pedicels 0.5-1 mm long, 1-1.5 mm diameter; sepals oblong, acuminate to rounded, green, apically brown-reddish, 2-2.5 × 1.2-1.5 mm, slightly erose, lepidote, 5-nerved, shorter than petals; petals oblong to oblong-elliptic, acuminate, 4.3-4.8 × 2.8-3.2 mm, widely spread, apically white, basally light pink, 7-nerved; stamens with triangular filaments, flattened, 3-4 mm long, white, adnate to the base of pistillode; anthers oblong, ca. 0.7-1 mm long, dorsifixed, green-yellowish; pistillode reduced, white, ca. 1.5 × 1.2 mm, stigmatic lobes reduced, erect, ca. 0.5 mm long.
Pistillate inflorescences a 1-divided panicle, some basal branches 2-divided, in general shape ovoid (larger branches at the middle part of the axis), erect, ca. 1 m up to 2 m long when growing on the shade and then, elongated and then longer and gangly; peduncle terete, 30-40 cm long, 6-11 mm diameter at the base, glabrous; internodes 3.5-6 cm long, green, glabrous, sparsely white lepidote where bracts are inserted; peduncle bracts with blades and laminae without a clear division, wide triangular, acute, acuminate, 5.5-9 mm long, 1.5 cm wide, drying light brown, entire, margins thin, multinerved, glabrous above, basally white lepidote below, larger to equaling the length of the internodes; rachis 60-90 cm long, ca. 1 cm diameter at the base, terete, light green, internodes 1.5-3.5(-5) cm long; primary bracts triangular, long acuminate, 3-4.5 cm long, 4-10 mm wide, longer to equaling the length of the stipe; stipes (1.5-)3-4.5 cm long, flattened; branches 20-22 in number, pedicellate, ascending, (3-12)20-25 cm long, with 20-50 flowers; branch rachis terete, glabrous, smooth, slightly ribbed when dry, green; floral bracts triangular-oblong, acuminate, 2.8-3 × 1.8-2.2 mm, margin erose, 5-nerved, brown, sparsely white lepidote. Flowers with sepals and petals adnate to the ovary, fragrant during the morning, sweet aroma; pedicel terete, ribbed when dry, 3 mm long, ca. 1 mm diameter; sepals triangular, acuminate, 1.5-2.2 × 1.4-1.8 mm, basally green, apically brown, entire, sparsely white lepidote, 5-nerved; petals narrowly triangular, rounded, cucullate, entire, 4.5-5 × 2-2.5 mm, white, 7-nerved, adnate to the ovary; staminodes six, triangular, laminar, 3.2-3.5 mm long, as long at the ovary and attached to its base, white; ovary superior, oblongoid, 3.5-3.7 mm long, 2-2.3 mm diameter, green, slightly lepidote, stigmatic lobes recurved, 2-2.5 mm long, adnate at their bases, white, equaling the length of the petals in anthesis; placentation central, ovules white greenish. Fruits conical to cylindrical, 6-13 mm long, 2-3(-5) mm diameter, 1-2 cm apart, brown, smooth, glossy, with a conspicuous mid nerve in each carpel, sepals, petals and staminodes remnant, pedicel obconical, 1-2 mm long, ca. 1 mm diameter. Seeds fusiform, 5-7 cm long, dorsal wing with two cauda at each end, brown.
Distribution and ecology. Hechtia chamelensis is currently known only from the Chamela-Cuixmala Biosphere Reserve in the Mexican state of Jalisco, but it could be found in localities near the reserve, along the coast, due to the similarity of the vegetation type. The distribution of this species occurs within the biogeographic province of the Pacific Lowland (sensuMorrone et al. 2014), characterized by dry weather at elevations below to 300 meters. Plants of Hechtia chamelensis have been found in dense groups of rosettes, growing as lithophytes, mainly on sun-exposed rocky slopes, inside tropical deciduous forest vegetation (Rzedowski 1978), also sometimes in thicket of secondary vegetation, frequently accompanied in the tree layer by Plumeria rubra L. (Apocynaceae), Bursera spp. (Burseraceae), Cordia alliodora (Ruiz & Pav.) Oken (Cordiaceae no Boraginaceae), Forchhammeria pallida Liebm. (Resedaceae), Leucaena lanceolata S.Watson, Libidibia sclerocarpa (Standl.) Britton & Rose, Lonchocarpus sp. (Fabaceae), Ruprechtia fusca Fernald (Polygonaceae), Thouinidium decandrum (Bonpl.) Radlk., Thouinia paucidentata Radlk. (Sapindaceae), Vitex hemsleyi Briq. (Lamiaceae); in the shrub layer species such as Comocladia engleriana Loes. (Anacardiaceae), Cnidoscolus spinosus Lundell, Jatropha sp., Acalypha langiana Müll. Arg., Croton niveus Jacq. (Euphorbiaceae), Coursetia caribaea (Jacq.) Lavin (Fabaceae), Piper sp. (Piperaceae); in the understory or herb layer Agave colimana Gentry (Asparagaceae), Commelina erecta L. (Commelinaceae), Encyclia adenocarpos (Lex.) Schltr. (Orchidaceae), Tillandsia paucifolia Baker subsp. schubertii F. Ebel & J. Röth (Bromeliaceae), Elytraria imbricata (Vahl) Pers. (Acanthaceae), Lasiacis ruscifolia (Kunth) Hitchc. (Poaceae), Mirabilis russellii Le Duc (Nyctaginaceae), Desmodium procumbens (Mill.) Hitchc. (Fabaceae), Salvia languidula Epling (Lamiaceae), and some climbing species such as Ipomoea trichocarpa Elliott (Convolvulaceae), Melothria pendula L. (Cucurbitaceae), Cardiospermum halicacabum L., Paullinia cururu L. (Sapindaceae), and Ruehssia lanata (Paul G. Wilson) L.O. Alvarado (Apocynaceae).
Preliminary conservation status. Hechtia chamelensis is currently known from seven collections, separated by less than 1 km among them. All collections are inside the limits of the natural protected area Chamela-Cuixmala Biosphere Reserve, in the municipality of La Huerta, Jalisco. Using GeoCAT (Bachman et al. 2011) and according to the limited number of localities, the Extent of Occurrence (EOO) is 0.436 km², meanwhile the size of the Area of Occupancy (AOO) is 0.094 km² (based on cells of 1 × 1 km). Following the IUCN (2012) criteria, this species is considered Critically Endangered (CR B1ab(i,ii), B2ab(i,ii)) given the AOO and EOO values, but a preliminary category of Endangered (EN) is proposed following the IUCN (2022) criteria, because the species is found in a protected natural area, which reduces the risk, ensuring its protection.
Phenology. It has been collected in bloom in September, and in fruit from September to March.
Etymology. Herbarium specimens of the new taxon were first identified as a new species by Patricia Magaña (proposing Hechtia chamelensis as its name; Magaña-Rueda 1986) but was never described until now. The species epithet refers to the type locality and recognizes the value of the Chamela-Cuixmala Biosphere Reserve on preserving a large area of dry tropical forest, one of the most important, although threatened, vegetation types in Mexico.
Additional specimens examined (paratypes). Mexico: Jalisco: Mun. La Huerta, estación biológica de Chamela, ruta del sendero Calandria, 19° 30' 16'' N, 105° 02' 12.8'' W, ca. 92 m, matorral xerófilo en una matriz de bosque seco tropical, colectada estéril el 1 julio 2014, por I. Ramírez, P. Carrillo, W. Cetzal & J. L. Tapia, florece en cultivo en 3 agosto 2019, Ivón Ramírez 2429 ♂ (CICY, IBUG); otro espécimen fue recolectado al final del sendero Calandria, al NE de la estación biológica de Chamela, 19° 29’ 59’’ N, 105° 2’ 3’’ W, 60 m, 14 October 1997, J. Calónico S. 4867 fruits (MEXU-1063806!, MEXU-1030539! [FOTO CICY-067024!]); estación biológica de Chamela, ruta del sendero Calandria, 19° 30' 16'' N, 105° 02' 12.8'' W, ca. 92 m, matorral xerófilo en una matriz de bosque seco tropical, I. Ramírez, P. Carrillo, W. Cetzal & J. L. Tapia 1936 fruits (CICY-071967!, CICY-071966!, CICY-071969!, CICY-071968!, CICY-071970!); en la marca de 800 m en el sendero Calandria, dentro de la estación biológica Chamela, UNAM, 19° 30' 10.5" N, 105° 01' 56.4" W, 110 m, 26 September 1997, A. Domínguez M. 565 fruits (MEXU -1026066!; MEXU-1223257!); Bosque de la Enseñanza, estación de biología Chamela UNAM, Latitud: 19.50028°, Longitud: -105.04722°, 40 m, 10 July 1997, A. Domínguez 804 fruits (MEXU-1390563!, MEXU-1390564!); El Mirador, vereda Búho, estación biológica Chamela, UNAM, 6 March 1982, E. J. Lott 909 fruits (MEXU-321668, MEXU-CHAMELA s.n.).
Discussion
We propose a new species of Hechtia from the biogeographical province of Pacific Lowlands, from the Mexican state of Jalisco. Specimens under this species concept had been previously identified as Hechtia laevis or H. reticulata. Hechtia laevis was described from the Mexican state of Colima, and the holotype (McVaugh 15528, MICH!) consists of a fruiting branch, while the isotype (US00089093) has a leaf, a foliar sheath, three loose fruiting branches and a young staminate inflorescence with its branches barely developing. When comparing infructescence of Hechtia chamelensis with that of H. laevis (holotype and isotypes), the last one has densely arranged fruits, and stipes terete without primary bracts, while in H. chamelensis shows a conspicuous primary bract that is longer or rarely equaling the length of the stipe, stipe flattened, and fruits less densely arranged (ca. 5-6 fruits in 5 cm length vs. 40-50 fruits in the same length). Additionally, the very young staminate inflorescences on the isotypes (US00089093 and MICH) of H. laevis shows a thicker peduncle differing from that of H. chamelensis, staminate branches are impossible to compare since they are extremely young on both isotypes of H. laevis. However, leaf features do differ, H. chamelensis has wider leaves (1-3(-4) cm vs. 2.6-2.8 cm wide) and glabrous and shiny above (easily seen in the holotype of the species vs. lepidote, glaucous above), spines 1.5-2.5 (-5) mm long, 0.4-1(-1.5) cm apart vs. ca. 3 mm long vs. ca. 1.5 mm apart). All these features support the recognition of two different entities.
On the other hand, Hechtia reticulata was described from the Mexican state of Colima. The holotype (Palmer 1352, GH!) just shows some loose fruiting branches, while isotypes (F, US) show infructescence´s features. Comparing these available characters with those in Hechtia chamelensis fruits, in the former there are 8-12 per 5 cm length (vs. 5-6 fruits), length of the fruits is similar (ca. 9 mm long vs. 1 cm long), seeds differ in length (3 mm vs. 5-7 mm). The paratype of Hechtia reticulata (Ferris 6111, GH!) has fruits and seeds (in a small envelope) and a sketch of leaf margins on the holotype: foliar margin differs between H. chamelensis and H. reticulata: the margins are serrate in both cases, but spines are different in size (at least proportionately since there is not scale on the drawing on the paratype), and the new taxon shows a more sinuous margins, with concavities between spines (Figure 5). It is important to comment that McVaugh (1989) mentioned that H. laevis and H. reticulata are almost identical only differing in the texture of the fruits, smooth on the first, reticulate on the second. This species pair needs further investigation in order to circumscribed each one with the aid of more evidence.
Figure 5 A comparison of some features of Hechtia chamelensis, H. laevis and H. reticulata; A) holotype (MEXU-676801-C!) of Hechtia chamelensis showing features of a staminate inflorescence and leaf, especially foliar margins; B) isotype of Hechtia laevis (US-2429395!) showing features of leaves, especially foliar margins, immature staminate inflorescence, and branches with fruits; C) isotype of Hechtia reticulata (F!), showing a partial infructescence, with no leaves; D) a handmade drawing of foliar margins made by Lyman Smith on the paratype of Hechtia reticulata (GH!); E) seeds of H. chamelensis; F) seeds of H. reticulata; G) seeds of H. laevis.
Another specimen (Solís Magallanes 4090, SLPM!, TEX!) from isla la Pajarera in Chamela Bay, was compared to the new species. The specimen represents a pistillate inflorescence only, and it is very similar to the pistillate inflorescences of the new species, but the flowers are almost sessile (vs. pedicellate) and there is no information on the leaves, fruits, or staminate flowers, so we do not assign it to the new species. Similarly, we studied a pistillate specimen collected on the same island by Carmen del Río (75, MEXU) and the branches are ribbed and the flowers are sessile. This specimen was not assigned to the new species either, since in H. chamelensis the branches are terete, and the flowers are pedicellate.
Hechtia chamelensis is one the species until now, with the larger staminate flower known in the genus, surpassed by Hechtia matudae L.B.Sm. with staminate flowers 1-1.5 cm diameter (López-Ferrari et al. 2008). Petals of staminate flowers in the new taxon are white with pink dots at their bases or almost absent and then petals yellowish. Pistillate flowers are very inconspicuous, white petals and these form a cup-like corolla during anthesis, with white stigmatic lobes. Both flowers are fragrant during morning hours and visited by bees (Apis mellifera L. and Meliponini bee species).
