Two new species of nopal (Opuntia, Cactaceae) from the Baja California Peninsula (Mexico) Muñoz, Fermín Mercado Luz, José Luis León De La Rebman, Jon P. Narváez, Alfonso Medel Ramos, Rafael Campos Phytotaxa 2021 2021-06-24 508 3 266 278 8RTMP Mercado & Leon de la Luz Mercado & Leon de la Luz 2021 [136,663,1238,1265] Magnoliopsida Cactaceae Opuntia Plantae Caryophyllales 6 272 Tracheophyta species caboensis sp. nov.   Type:—  MEXICO. Baja California Sur: municipio  La Paz, paraje  La Piedra Bonita, ladera de exposición al Suren el Cañon de La Burrera, 3.5 kmal SW del Valle de La Laguna, 23.521542° N, 109. 999775° W,  1102 m, transición bosque de encino y selva baja caducifolia,  14 May 2008,  J.L. León de la Luz08-087( holotypeHCIB 31865!, isotypes to be deposited at MEXU!). Erect and ascending plants up to 2 mtall, evenly branched; basal cladodes dark brown, woody in appearance, lacking spines, upper and new cladodes yellowish-green, in times of water stress the areolar zone is pigmented with purple spots, particularly in the upper portion of the pads, sometimes covering the whole pad. Young cladodeswith conical recurved-descending ephemeral leaves, these born at the base of the areoles, up to 5 mmlong, reddish turning yellowish-green, rostrate, circular areoles with felt or gray-white wool and numerous yellow glochids in the center up to 1.5 mmlong; pad epidermis with velvety texture to touch. Mature cladodesobovate to orbicular, yellowish green when hydrated, 17–20(–23) cm long, 8–14 cmwide, pad surface still somewhat velvety to touch throughout, but turning papillose on older cladodes; each with 2–9 diagonal series of areoles 0.7–1 cmseparated from each other, oval or circular, 1–1.5 mmin diameter, with brown wool and yellowish glochids, when stressed purple spots appear around the areoles, at times forming obvious purple stripes on the surface of the whole cladode, numerous glochids 2 mmlong, generally without spines, but when present 1–2(–3) straight, porrect, yellowish turning gray and only in the areoles of the upper third, or vestigial at the cladode margin, acicular to subulate, 1–2(–2.5) cm long. Flower budson the cladode edge, rarely on the face of the cladodes, areoles in 5–6 semi-spiral series, with white-gray wool and small, yellow and glochids of uneven length, 1–3 mmlong, more or less persistent; outer segments of the perianth in 3 series, pink or reddish turning yellow, persisting red in the central-upper part, the apical or superior areoles of the pericarpel all alike. Flowersrotate at anthesis, 5.5–7.5 cmin diameter, inner perianth segments yellow, 4–4.5 cmlong, 1.2–1.5 cmwide, oblong, with denticulate upper margins, accuminate, outer segments sometimes pink to reddish on the apical mucro; stamensnumerous, filaments yellow, sometimes ferruginous; antherswhite; stylewhite to yellow, 2.4–2.8 cmlong; stigmathe same color as the style or greenish, with 5–6 digitate lobes to 2 mmlong, short rostrate; ovarycavity obovoid to obconic 4–7 mmlong, 3–5 mmwide, with numerous ovules; pollenspherical to tetragonal, apolar, 60–90 µm in diameter, periporate, tectum reticulate, smooth walls, 10–14 circular pores, 12–19 µm in diameter; pericarpelvelvety pubescent to touch, obconic 3.5–4.5 cmlong, with 4–5 oblique series of areoles, with persistent and abundant glochids, small, yellow. Fruitovoid to obovoid, 4–4.5(–5) cm long, 3–4 cmin diameter, both cuticle and pulp green, becoming somewhat yellowish when ripe after 5–8 months, outer wall 2–3 mmthick when fresh; receptaclevariable, 0.4–0.6 cmdeep; seedssemi-circular 3–4 mmin diameter, grayish in color. Chromosomal number 2n = 4X = 44 ( F. Mercado Muñoz490).    Paratypes:— MEXICO. Baja California Sur, municipio  La Paz, camino de terracería  San Antonio de la Sierraa rancho  La Victoria, 23.623565° N, 110.916394° W,  1084 m, bosque de encinos,  17 May 2012,  F. Mercado Muñoz464(to be deposited at ARIZ); municipio Los Cabos, inmediaciones de la ranchería La Cieneguita, Sierra San Lázaro, 23.238237° N, 109.952748° W,  772 m, selva baja caducifolia,  7 May 2013,  F. Mercado Muñoz526(to be deposited at USON); municipio La Paz, Caminopor la entrada a San Blas Sierra Las Calabazas, 23.8489°N- 110.1957°W,  373 m,  11 April 2013,  F. Mercado Muñoz513(SD 265354); Municipio La Paz, Ensenada de Muertos,  40 m, 23.9781°N- 109.8371°W,  2 April 1952,  R.V. Moran3565(SD 45886); Ensenada de Muertos, 23.9781°N- 109.8371°W,  40 m,  2 April 1952,  G. Lindsays/n(MEXU 45886); near Punta Frailes, 23.3698°N- 109.4389°W,  20 m,  4 April 1937,  P.J. Rempel320(RSA 442409);   7 kmW Rancho El Saltito, 23.2385°N- 110.1961°W,  150 m,  8 November 1971,  G.A. Voss1185(SD 234104), near San Bartolo town, 23.7388°N- 109.8638°W,  439 m,  1 July 1973,  A.C. Gibson3004(ARIZ 210374);  1 kmSE Presa Santa Ines, 23.5441°N- 110.1359°W,  337 m,  17 May 1992,  J.P. Rebman1379(BCMEX 5122); near rancho Alvaro Obregón, 23.8845°N- 110.2127°W,  90 m,  8 August 1994,  J.P. Rebman2488(SD 138273); Sierra La Victoria, near Rancho La Concepción, 23.6448°N- 109.9071°W,  720 m,  3 February 1996,  M.A. Baker12163(SD 139848); Sierra La Victoria, road  La Concepción, 23.6338°N- 109.8883°W,  700 m,  5 February 1996,  M.A. Baker12173(ASU 205475); 15 Km NE Cabo San Lucas,  Arroyo El Tule, 22.9598°N- 109.8024°W,  6 m,  13 April 1977,  J.A. Tonix17(MEXU 204340); Municipio Los Cabos, near San Josédel Cabo, 23.0663°N- 109.6651°W,  15 m,  25 March 1911,  J.N. Rose16470(NY).   Etymology:—The specific epithet is derived from the toponym “Región de Los Cabos” referring to the Cape region, the extreme southern extent of the Baja Californiapeninsula. In turn, the epithet “Cabos” is also related to the two main towns in the area, CaboSan Lucas and San José del Cabo.   Distribution and habitat:—It should be noted that both of these new species overlap in their distributions in the Caperegion’s mountains, specifically in the northern portion, an area called the Sierra de La Victoria ( 23.602°N). Both species are less common in the Cape’s southern mountains (Sierra San Lázaro, 23.252°N). However, in the eastern portion (slopes toward the Gulf of California) both species populations are more common than in the western slopes of the Pacific, where they are infrequent (see Figure 1).   Opuntia sierralagunensisoccurs in dry tropical forest, from 400 min elevation, to the limits with the oak woodland at about 1400 m. Regarding  O. caboensis, it can be found most commonly between (10–) 100–1100 min elevation. Both of these new species appear to have healthy populations in the elevation belt where they come into contact with the lowest oaks (  Quercusspp.), around 700–900 min the Sierra La Victoria. Apparently, the incidence of winter frosts restricts their distribution to higher elevations, although a sole plant of  O. sierralagunensiswas seen growing underneath pine trees at 1600 m. Also, the populations along the coastal strip are uncommon, however most of the herbarium specimens historically came from it.  Phenology:—The shrubby spreading habit of some  O. sierralagunensisindividuals might be attributed to the impacts of forage pressure from cattle that graze freely in the region, since some plants that were out of reach from cattle tended to have more erect growth habits and were taller, reaching up to  2 m.Although  O. caboensishas a low number of spines, the areoles do have abundant glochids that might possibly act as a deterrent against some livestock grazing ( Fig. 5 A, B). For both species, flowering episode begins during the early spring (March), pollination seems to occur by native bees (  Augochloropsissp., and  Diadasiasp.) that are common visitors during mid-day, as well as Nitidulidaeand Cantharidaebeetles, and several ant species. Flowering ends during the dry and warm summer, when the water stress in the cladodes is noticeable. When the summer rains arrive (August-September), the plants rehydrate quickly and the fruits reach the last stage. In  O. sierralagunensisthe fruits ripen when they change their color from green to red ( Fig. 3F), they are promptly consumed by birds and other fauna. For  O. caboensis, the ever-green fruits show a noticeably low rate of setting and take more time to ripen, since they remain on the cladodes until winter or even into spring ( Fig. 5F). In both cases, the seeds have a viability greater than 50%, but the majority of propagation for both species appears to be vegetative and occurs mainly from the detachment and rooting of the stem cladodes.   FIGURE 5.  Opuntia caboensis sp. nov.A. Cladodes with red spots when stressed during the dry season; B. Cladode with few spines only in the upper third, and the presence of cochineal. Note also the velvety stem surface; C. Pericarpelar view; D. Flower view; E. Longitudinal cut of the flower, note greenish to yellowish color of the pistil; F. Mature fruit after ca. 8 months of development. Also, for both species, the development of new stem cladodes occurs from the spring months and continues until the onset of summer rains. The flowers develop on these new pads the following spring, new pads sprout mostly from 2–3 year old pads. Some immature pads are heavily attacked by herbivorous insects (such as  Moneilemasp.) and others, possibly due to their soft texture and lack of any apparent structural defenses. The extreme results are deformities in the growth of these cladodes, and an eventual lack of vegetative growth. Due to the presence of cochineal (  Dactylopius opuntiaeCockerell) colonies on some  O. caboensispads ( Fig. 5 B), there might be additional impacts that affect fitness and growth of these individuals. Finally, in respect to another important diagnostic character found in  O. caboensis, when water stress begins during the dry season (in May), red spots develop and spread from each areole to cover wide strips on the surface of the cladodes, sometimes all of them ( Fig 5A). This species shares this character with the partially sympatric  O. bravoana, which has caused misidentifications by novice botanists. Table 1shows additional taxonomical traits to take in account to separate them.  Conservation status:—Considering their irregular distributions in the tropical deciduous forest portions of the mountains of the Cape region, the relative low density of individuals in populations, as well as the herbivory pressure from cattle throughout their ranges, both  O. sierralagunensisand  O. caboensiscould likely be considered as threatened or vulnerable species. Population studies should be conducted on both of these new species following IUCN and Mexican regulatory protocols in order to assess and categorize them accurately. 2008-05-14 La Paz & La Piedra Bonita & el Canon de La Burrera & J. L. Leon de la Luz Mexico La Paz 1102 23.521542 Sur 1 -109.99978 La Piedra Bonita 6 272 1 Baja California Sur holotype SD 265354 1937-04-04 2013-05-07 1937-04-04 La Paz & San Antonio de la Sierra & La Victoria & F. Mercado Munoz & Los Cabos & La Cieneguita & Sierra San Lazaro & Camino & San Blas Sierra Las Calabazas & de Muertos & R. V. Moran & G. Lindsay & Punta Frailes & P. J. Rempel Mexico La Paz 1084 23.3698 La Victoria 7 -109.4389 San Antonio de la Sierra 7 273 1 Baja California Sur paratype SD 234104, SD 138273, SD 139848 1911-03-25 1996-02-05 1911-03-25 G. A. Voss & A. C. Gibson & J. P. Rebman & M. A. Baker & La Concepcion & Km NE & Arroyo El Tule & J. A. Tonix & J. N. Rose South Africa San Bartolo town 150 23.0663 Rancho La Concepcion 7 -109.6651 Sierra La Victoria 7 273 1 Western Cape paratype