Leptocereus velozianus Clase, Y.Encarn., Peguero & Majure, 2021

Majure, Lucas C., Encarnacion, Yuley, Clase, Teodoro, Peguero, Brigido, Ho, Kelly & Barrios, Duniel, 2021, Phylogenetics of Leptocereus (Cactaceae) on Hispaniola: clarifying species limits in the L. weingartianus complex and a new species from the Sierra de Bahoruco, PhytoKeys 172, pp. 17-37 : 17

1. Leptocereus velozianus Clase, Y.Encarn., Peguero & Majure sp. nov. Figs 2 , 3 , 4

Type.

República Dominicana. Prov. Independencia. Sierra de Bahoruco, Parque Nacional Sierra de Bahoruco, Puerto Escondido, Rabo de Gato, 433 m, 14 mayo 2019, Majure 7843 (Holotype: JBSD!, Isotype: FLAS!).

Diagnosis.

Differing from both L. weingartianus and L. demissus by the white young spines (vs. yellowish spines) and larger stem diameter (up to 3.7 cm in diameter in L. velozianus ). Differing from L. demissus by the erect, primary trunk rather than the sprawling growth form, and oblong hypanthium in L. velozianus rather than obconic hypanthium as in L. demissus .

Description.

Erect shrubs or small trees 2-4 m tall, ultimate stem segments often sprawling among associate vegetation in smaller individuals, or merely pendent on larger individuals, 13-40+ cm long, 2.7-3.7 cm wide, ribs 4-5 per stem, 12-17 mm deep, rib margins strongly crenate, 18-28 mm between areoles, spines white (or yellowish around the developing base), aging gray, tips brownish-red to black, 13-15 per areole, erect, central spine 16-22 mm long, longest radial spines 18-30 mm long, shortest pair of reflexed radial spines at base of areole, 3-6 mm long, a tuft of brown, crisped trichomes filling areoles; flower, including hypanthium, ca. 7.6 cm long, spiny, outer tepals green, inner tepals greenish-white, apices obtuse, anthers white, 1.3-1.5 mm long, style ca. 3 cm long, stigma included in the corolla, lobes 8, pale green, apparently at the level of the ring of anthers, nectar chamber about 8 mm wide, immature fruit, 5-7.5 × 2.6-3.4 cm (excluding dried perianth), lustrous green, spiny, areoles ca. 28-36, with 8-13 spines, those 3-12 mm long, strongly brownish-red and white banded, the tips dark brownish-red to black, seeds 3.3-3.7 × 2.3-2.5 mm, dull black (only appearing shiny when not cleaned) with colliculate-pitted surface.

Etymology.

The specific epithet, " Leptocereus velozianus " is given honoring the Dominican botanist Alberto Veloz, who is the Head and Curator of the Herbarium JBSD of the "Dr. Rafael M. Moscoso" National Botanical Garden of Dominican Republic. For 27 years, Veloz has dedicated his life to the study of the Hispaniolan flora and has conducted extensive fieldwork across the island, with many collections from the Sierra de Bahoruco, where this new species was found. Together with other botanists he has collected over 10,000 specimens and has published several papers on the flora in national and international journals. His publications have included different approaches, such as floristics, taxonomy, ecology and conservation. Veloz has also contributed to the formation of young botanists by involving students as part of the staff in the herbarium JBSD and through fieldwork.

Distribution and habitat.

Leptocereus velozanius grows in well-formed, seasonally dry tropical forest over limestone from around 158-433 m in elevation occurring with the following associate species: Bursera simaruba Sarg., Celtis ehrenbergiana (Klotzsch.) Liebm., Coccoloba diversifolia Jacq., Consolea microcarpa (K.Schum.) E.F.Anderson, Cordia globosa Kunth, Cylindropuntia caribaea (Britton & Rose) F.M.Knuth, Eugenia rhombea (O.Berg.) Krug & Urb., Gouania lupuloides Urb., Guaiacum sanctum L., Helicteres semitriloba Bert. ex DC., Hybanthus havanensis Jacq., Krugiodendron ferreum Urb., Leptocereus weingartianus (E.Hartmann) Britton & Rose, Melochia tomentosa L., Opuntia repens Bello, Pisonia aculeata L., Phyllostylon rhamnoides (J.Poiss.) Taub., Prosopis juliflora (Sw.) DC., Senna angustisiliqua (Lam.) H.S.Irwin & Barneby, Senegalia skleroxyla (Tussac) Seigler & Ebinger, Tournefortia stenophylla Urb., Zanthoxylum nashii P.Wilson, Ziziphus rignonii Delponte. Currently, the species is only known from the northwestern slope of the Sierra de Bahoruco, southwest of the town of Jimaní (Fig. 4 ). Given the extent of tropical dry forest in and around that area, it is very likely that more localities of this species will be found.

Phenology.

Leptocereus velozianus has been collected in flower and immature fruit during May and with mature fruit in June, July and November. Thus, it appears likely that L. velozianus may flower over the early to mid-summer months with fruit ripening later in the year.

Conservation status.

Formal evaluation of conservation status will be undertaken by Encarnación (in prep.) for L. velozianus based on further field work and demographic study. However, based on the currently known limited distribution of the species, the few numbers of individuals that have been observed, as well as anthropogenic activity near populations of the species, we consider that this species could be Near Threatened based on IUCN criteria. Further fieldwork will be essential for providing a comprehensive assessment of the conservation status of L. velozianus . Fortunately, the larger population known for this species is within the Sierra de Bahoruco National Park, so it is mostly protected from large-scale anthropogenic disturbances. Furthermore, the SDTF in that area is very well developed (i.e., non-fragmented) and should provide extra protection for the species.

Additional specimens examined.

Dominican Republic. Prov. Independencia. Sierra de Bahoruco, municipio Duvergé, comunidad Puerto Escondido, lugar denominado Rabo de Gato, yendo hacia Cañada de Pedro Bello, 26 jun 2013, Clase et al. 8004 (JBSD). Sierra de Bahoruco, municipio Duvergé, Rabo de Gato, yendo hacía la cañada La Cuaba, Pedro Bello, 23 nov 2017, Clase et al. 9931 (JBSD). Sierra de Bahoruco, municipio Duvergé, Puerto Escondido, lugar denominado Rabo de Gato, yendo hacía la Cañada de Pedro Bello, 27 jul 2017, Clase et al. 10202 (JBSD). Sierra de Bahoruco, municipio Jimaní, yendo desde El Limón, lugar denominado Guzmán, lado Sur de la carretera, 27 jul 2017, Clase et al. 10205 (JBSD). Sierra de Bahoruco, justo al Este de Jimaní en la carretera 46 (entre Jimaní y El Limón) en el lugar denominado Guzmán; 158 m, 14 mayo 2019, Majure 7842 (FLAS, JBSD). Parque Nacional Sierra de Bahoruco, Puerto Escondido, Rabo de Gato; 433 m, 14 mayo 2019, Majure 7851 (FLAS, JBSD).

Figures

Figure 2. Photographic plate of L. velozianus A small tree habit of L. velozianus alongside T. Clase for scale B, C arching branches and spine color D trunk and bark E growing stem showing white spines as they mature F spiny, immature fruit G colliculate-pitted seed, and H stems with immature fruit, showing crenate rib margins. A, D, F, G from Majure 7851 B, C, H from Majure 7843, and E from Majure 7842. Photos taken by L. C. Majure.

Figure 3. Illustration of L. velozianus A-C stems showing crenate margins D, E cross sections showing 4 - 5 ribbed stems, also showing large crystals in the parenchyma F day old flower showing rounded external tepal apices and spiny pericarpel, and G immature fruit showing spiny pericarpel and remnant floral tube. A from Majure 7842, and B-F from Majure 7843.

Figure 4. Distribution map of L. demissus (black circles), L. paniculatus (open circles), and L. velozianus (black stars) on Hispaniola.