Hechtia santanae I. Ramírez & P. Carrillo, 2016

Ramírez-Morillo, Ivón, Carrillo-Reyes, Pablo, Tapia-Muñoz, José L. & Cetzal-Ix, William, 2016, An addition to genus Hechtia (Hechtioideae; Bromeliaceae) from Jalisco, Mexico, Phytotaxa 266 (4), pp. 261-270 : 262-268

Hechtia santanae I. Ramírez & P. Carrillo , sp. nov. ( Figs. 1–4 , Table 1)

The new species is similar to H. laevis L. B. Smith , a species native of the neighboring state of Colima, from which it differs in its rhizomatose habit (vs. no discernable rhizomes), shorter leaves (leaves 12–34 vs. 60 cm long), sparsely white lepidote on both surfaces (vs. glabrous above and lepidote below), staminate and pistillate branches with several basal bracts vs. without basal bracts, when in fruit, shorter pistillate branches (ca. 4–9.5 vs. 15 cm long), pistillate flowers with non-articulate pedicels (vs. articulate), sepals triangular, acute, 2.4–2.9 mm long (vs. widely ovate, apiculate, 1.5 mm long), and petals oblong, 4.7–5 mm long (vs. triangular, 3.5 mm long.

Type: — MEXICO. Jalisco: Municipio Tuxcacuesco, desvío de la carretera 429 tomando la brecha a El Agua Dulce, ca. 1 km SO de San Buenaventura , 19°45’32.9’’N, 104°02’49’’W, 840 m, 2 July 2014, Ramírez, Carrillo-Reyes, Santana-Michel, Tapia & Cetzal 1940 ♂ (Holotype CICY; isotypes IBUG, MEXU, US, ZEA) .

Epitype (designated here):— MEXICO. Jalisco: Municipio Tuxcacuesco, desvío de la carretera 429 tomando la brecha a El Agua Dulce, ca. 1 km SO de San Buenaventura, 19°45’32.9’’N, 104°02’49’’W, 840 m, 2 July 2014, Ramírez, Carrillo-Reyes, Santana-Michel, Tapia & Cetzal 1941b ♀ (Epitype, CICY).

Plants lithophytic, rosettes caespitose, globose, 20–30 cm height, 20–40 cm in diameter, producing basal rhizomes and forming colonies of 3–7 or more rosettes. Rhizomes medium size, 6–10 cm long, 3–4 cm diameter. Leaves (20–) 30–40 in number, central ones erect, basal ones slightly reflexed; sheaths widely ovate to widely oblong, 3–4 × 3.5–4.8 cm, pale yellow with light brown spots when dry, glabrous in the middle area but featuring white lepidote margins and at distal end, margins finely spiny; blades narrowly triangular, attenuate, 12–34 × (1.2–) 1.7–2.8 cm, succulent, green, occasionally with reddish margins, densely to sparsely silvery lepidote adaxially, densely white lepidote abaxially, margins spiny; spines antrorse, triangular, 1–3 mm long, 4–17 mm apart, brownish, with a short tuff of white trichomes at the axil of basal spines. Inflorescence central, emerging from the center of a newly-forming rosette (growth pattern SPFP sensu Ramírez et al., 2014), sometimes tips of branches brown, without flowers (probably abortive floral buds).

Staminate inflorescence a 1-divided panicle, cylindrical, erect, 0.8–1.10 m long; peduncle terete, 24–34 cm long, 0.5–1 cm diameter at the base, reddish, surface waxy, twice to almost three times longer than rosette height but shorter than main axis of the inflorescence, internodes 1–2.5 cm long; peduncle bracts triangular, long attenuate, acute, 2–9 × 0.7–0.9 cm, brownish, erose at base, sparsely spiny to the apex, multinerved, glabrous at base and densely white toward apex on both surfaces, usually longer than internodes but occasionally as long as the internodes; main axis 54– 73 cm long, 5–6 mm in diameter at the base, terete, reddish, surface waxy, internodes 0.5–2 cm long; primary bracts ovate-triangular, attenuate, acute, 1–1.8(–2.5) × 0.4–0.7 cm, papiraceous, usually shorter than the stipe of the branch, entire to rarely erose, sometimes spinulose, brownish, multinerved, sparsely lepidote on both surfaces; branches (35–) 40–45 in number, forming an angle of 45°–75° or smaller relative to the main axis, (3.5–) 5.5–13.5 cm long, 1.5–2 cm diameter, each with 60–100 flowers; stipe of the branch 1–6 cm long, covered by bracts similar to the floral bracts; rachis 1–2 mm diameter, dorsiventrally flattened; floral bracts oblong-triangular, acuminate, 3.4–3.9(–5) × 2.2–2.4 mm, purple with a brown apex, margins erose and hyaline, glabrous, 3–5 nerved, shorter than sepals at anthesis. Flowers subsessile, erect, 5–5.5 mm long, 3.8–4.2 mm diameter, actinomorphic; pedicels obconic, 1 mm long, ca. 1.5 mm diameter; sepals ovate, acute, purple with a brown apex, 2.3–2.7 × 1.8–2.3 mm, entire, glabrous, 3-nerved, shorter than petals; petals elliptic, rounded, 4.3–4.8 × 3–3.2 mm, white, 7–9 nerved; filaments triangular, flattened, 3.8–4.4 mm long, white; anthers oblong, ca. 2–2.2 mm long, dorsifixed, reddish; pistillode reduced, pale purple to reddish, ca. 1 mm long.

Pistillate inflorescences a 1-divided panicle, cylindrical, erect, 1.10–1.40 m long; peduncle terete, 58–72 cm long, 0.6–1 cm diameter at the base, much longer than rosette height and as long as the main axis, green with purple hues, waxy surface, internodes 0.8–3.5 cm long; peduncle bracts triangular, acute, long-attenuate, 1.4–10.5 cm long, 0.4–1.4 cm wide, brownish, margins entire to erose at base, sparsely spinulose toward apex, multinerved, glabrous at base to densely white lepidote towards the apex on both surfaces, usually longer to rarely equaling the internode length; main axis 51–66 cm long, 4–5 mm in diameter at the base, terete, green, some sections are reddish, provided with a waxy cover, internodes 0.5–2 cm long; primary bracts ovate-triangular, attenuate, acute, 0.8–1.6 × 0.4–0.8 cm, entire to erose to sometimes spinulose, brownish, multinerved, sparsely white-lepidote on both surfaces, usually shorter than the stipe of the branches; branches 30–37 in number, forming an angle of ca. 45° with the main axis, 4–9.5 cm long, 10–50 flowered, stipe of the branch 0.8–2.5 cm long, rarely completely absent and sessile; rachis 1–2 mm diameter, dorsiventrally flattened, green, some sections are reddish, stipe of the branch absent or 1–1.5(–2) cm long; floral bracts oblong, acuminate, 4–4.2 × 3–3.2 mm, margin erose, hyaline, purple, apex brownish, 3-nerved, longer than sepals at anthesis, adnate to the pedicel for more than half of its length. Flowers 5.7–6 mm long, 3–4 mm diameter, pedicellate, actinomorphic, erect; pedicel terete, 2.8–3.2 mm long, ca. 1 mm diameter; sepals triangular, acute, 2.4–2.9 × 2–2.2 mm, purple with a brownish apex, entire, glabrous, 1-nerved, shorter than petals; petals oblong, acute, 4.7–5 × 2–2.2 mm, entire, white-purplish; staminodes six in number, triangular, laminar, 2.5–3 mm long, white; ovary superior, oblong to ellipsoid, 3–3.2 mm long, 1.7–2 mm in diameter, purple to reddish, glabrous; stigmatic lobes recurved, 1.2–1.7 mm long, adnate at their bases, white, equaling the petals at anthesis; placentation central. Fruits ovoid to narrowly ovoid, 6–11 mm long, (2–) 3–4 mm in diameter, scattered lepidote, brown when mature; seeds fusiform, brown to reddish brown, reticulate, 5–6.8 mm long, ca. 1 mm diameter, with a lateral wing ending in two hyaline caudae.

Distribution and habitat: — Hechtia santanae is known from four localities in the Municipalities of Tuxcacuesco, San Gabriel, and Tolimán, in the floodplain and contiguous foothills of the Ayuquila river basin, in Southern Jalisco ( Figure 4 ). This area is a valley system which represents a dry enclave influenced by the rain shadow produced by the Sierra de Manantlán, Nevado de Colima and Volcán de Fuego. Some other endemic species of succulent plants has been described from this area ( Jimeno-Sevilla et al., 2015: 72). The Ayuquila river basin belongs to the Pacific Lowland biogeographic region ( Morrone, 2014) and to the ecoregion Bosques Secos de Jalisco ( WWF 2001). The new species forms large colonies on gypsum and limestone outcrops at 780–920 m elevation. The vegetation of all localities corresponds to tropical deciduous forest ( Rzedowski, 1978), along with Bursera fagaroides (Kunth 1824: 27) Engler (1880: 44) , B. schlechtendalii Engler (1883: 41) , Cyrtocarpa procera Kunth (in Humboldt et al. 1825: 20), Hintonia latiflora (Sessé & Mociño ex De Candolle 1830: 350) Bullock (1935: 4) , Mimosa rosei Robinson (1898: 317) , Stenocereus queretaroensis ( Weber 1891: 27) Buxbaum (1961: 101) , Wimmeria lanceolata Rose (1909: 283) , and Ziziphus amole (Sessé & Mociño 1888:38) Johnston (1963: 1021) . Locally it grows in association with Bletia sp. , Polianthes howardii Verhoek (1976: 365) , Selaginella lepidophylla ( Hooker & Greville 1830: 162) Spring (1840: 126) , and Tradescantia orchidophylla Rose & Hemsley (in Hooker 1897: pl. 2522).

Etymology: —The specific Latin epithet, s antanae, honors Francisco Javier Santana Michel (1958–2015) ( Figure 1A ), who, based on his profound knowledge of the flora of Jalisco took us to the type locality since he suspected that this species was new to science. Sadly, Francisco passed away recently while preparing the first draft of this article.

Additional specimens examined (paratypes):— MEXICO. Jalisco: Municipio Tuxcacuesco [originally assigned to El Limón], 4–5 km al SW de San Buenaventura, por la brecha a El Agua Dulce, 19°45’02’’N, 104°03’07’’W, 950 m, 24 April 1999, Santana-Michel & Cervantes 9355 fruits ( ZEA!). Same locality ; 9 September 2000, Santana-Michel 10407 ♀ ( CICY, IBUG, ZEA). Same locality, 2 July 2014, Ramírez et al. 1941, fruits ( CICY, IBUG, MEXU, SEL, UAMIZ, US, WU, ZEA) . A 3 km al W de Tuxcacuesco, camino a El Camichán, pendientes fuertes que dan al pueblo, 7 October 1982, Lott & Hernández M. 1370 fruits ( MEXU!). Municipio San Gabriel , 0.5 km O de Apulco, 19°44’15’’N, 103°54’20’’W, 920 m, 2 July 2014, Carrillo-Reyes et al. 7405 ♂ ( IBUG) ; 11 March 2016, Carrillo-Reyes et al. 8246 ♀ ( IBUG) ; Municipio Tolimán, Arroyo La Ciénega, ca. 1 km al N de Tolimán , 19°36’33.4’’N, 103°54’33’’W, 783 m, 13 January 2015, Carrillo-Reyes et al. 7627 ♂ ( IBUG!) ; Carrillo-Reyes et al. 7632, fruits ( CICY!, IBUG!) .

Discussion: —The species has been collected in the biogeographical region of Pacific Lowlands (Tierras Bajas del Pacífico, TBP, Morrone 2014), a narrow strip that extends from Mexico (Sinaloa) to Costa Rica. This region is one of the thirteen biogeographical provinces within the Megamexico III region (sensu Rzedowski, 1991) and houses the largest number of Hechtia species ( Pech-Cárdenas, 2015). Hechtia santanae is characterized by its relative small rosette, size not exceeding 40 cm in diameter and 30 cm in height, with succulent, rigid, light green leaves, covered by a silvery, shiny layer of trichomes. Rosettes produce basal rhizomes as well as basal new rosettes, thus mature individuals consist of small colonies of 3 to 7 (rarely more) rosettes ( Figure 1C ). Inflorescences emerge from the center of a newly-formed, still undeveloped rosette denominated SPFP pattern ( Ramírez Morillo et al., 2014) ( Figure 1C ) and rarely from mature rosettes, suggesting that both patterns are variations of a central inflorescence. All taxa with SPFP growth pattern comprise a group whose monophyletic origin has been tested with molecular and morphological evidence (Ramírez-Morillo unpubl.). Two remarkable characters distinguish H. santanae from other Hechtia species: female and male inflorescences have the same architecture (simple panicles) ( Figures 3A, B ), an uncommon feature in this group of dioecious species where male plants tend to have more branched inflorescences and more flowers than their female counterpart. The second key character is the presence of sterile bracts enclosing the base of the branches, giving the entire structure a scaly aspect ( Figures 3A, B ); these bracts are very similar to the floral bracts but sterile. This last feature has also been observed in Hechtia iltisii with the difference that the stipe of the branch is located at the tip of the branches not at the base ( Burt-Utley & Utley 1993: 225).

As mentioned above, specimens of Hechtia santanae were previously referred to H. laevis , particularly in fruiting stage (Lott & Hernández 1370, MEXU!). Hechtia laevis ( Fig. 1B ) is a species that grows on gypsum-rich soils in xerophytic scrubland or low forests in the state of Colima along the Colima-Manzanillo road; the two species can be distinguished easily using the character summarized in table 1.

IUCN Conservation assessment:— Hechtia santanae is currently known from few collections from four localities that are separated by no more than 23 km among them. All populations were found outside protected areas. At San Buenaventura, the population is located over a gypsum outcrop. Although the site is apparently not suitable for agriculture, low levels of perturbation by cattle have been observed. Neighboring areas to this population are heavily disturbed by agricultural activities. At Apulco (Municipio San Gabriel) and at Arroyo La Ciénaga (Municipio Tolimán), plants grow on vertical limestone cliffs that are inappropriate neither for agriculture nor for raising cattle. No threats were detected there. Using GeoCAT ( Bachman et al., 2011) and based on the limited number of localities, the Extent of Occurrence (EOO) is 130.064 km 2, meanwhile the size of the Area of Occupancy is 16 km 2, based on cells of 2 km. A preliminary category of Endangered (EN (B2 bii)) is proposed following the IUCN (2012) criteria.

Figures

FIGURE 1. A, C. Hechtia santanae I. Ramírez & P. Carrillo. A. Francisco Santana Michel at the type locality. B. Hechtia laevis L. B. Sm. in habitat. C. Rosettes in habitat, showing (arrow) rhizomes. (Photographs A, C by Pablo Carrillo-Reyes; B by Ivón M. Ramírez- Morillo).

FIGURE 2. A–D. Hechtia santanae I. Ramírez & P. Carrillo. A. Flowering plant in habitat. B. Pistillate flower. C. Staminate flower. D. Fruits (Photographs A by Ivón M. Ramírez-Morillo; B–D by Pablo Carrillo-Reyes).

FIGURE 3. A–B. Type specimens Hechtia santanae I. Ramírez & P. Carrillo.A. Pistillate plant (Based on Ramírez et al. 1941b♀, epitype CICY). B. Staminate plant (Based on Ramírez et al. 1940♂, holotype CICY).

FIGURE 4. Geographical distribution of Hechtia santanae I. Ramírez & P. Carrillo.