Nopalxochia phyllanthoides (DC.) Britton & Rose (1923: 205

Martínez-González, César Ramiro, Alcántara-Ayala, Othón, Luna-Vega, Isolda & García-Sandoval, Ricardo, 2015, Phylogenetic placement and new data on macro and micro morphology of Nopalxochia phyllanthoides (Cactaceae), an endangered species from Mexico, Phytotaxa 222 (4), pp. 241-250 : 243-247

Nopalxochia phyllanthoides (DC.) Britton & Rose (1923: 205 f, 207)

Bas.: Cactus phyllanthoides DC. (1813: 84)

Lectotype (designated here): — MEXICO. [icon] TAB. 247, Fig. 5 (Pluckenet 1692; image available from http://bibdigital.rjb.csic.es/ing/ Libro.php?Libro=4827&Pagina=131).

Epitype (designated here): — MEXICO. Hidalgo: El Damo, 5 km East from Tenango de Doria, 28 April 2007, Alcantara & Ponce 6875 (FCME-150648!).

Description (macromorphology): —Epiphyte or epipetric ramified plant ( Fig. 1A ), with lanceolate phylloclades ( Fig. 1B ), cute, with cylindrical bases, ca. 5 cm width, obtuse lobes, pale or dark green, sometimes reddish, midvein prominent, with little spines when young, caducous when old. Epidermis glabrous, irregular epidermal cells with smooth texture, anticlinal walls; paracytic stomata. The collateral branches are born frequently from the cylindrical part of the plant, but some are born from the applanate part. Collateral branches 15–30 cm wide, cylindrical base 5 to 10 cm long, applanate part 10–25 cm long, 2.5–4.0 wide and 0.3–0.4 cm thick; crenate margins, each undulation of 0.1–0.2 cm long; areoles located in the borders of the stem, with 3–4 small acicular spines from 0.2–0.3 cm long. The young plants have branches with 2–5 ribs, with areoles distant in 0.3–0.5 cm from each other, with 3–15 very fine acicular spines of 5 mm long. Solitary flowers ( Fig. 1C ), falsely zygomorphic ( Cruz-Espíndola & Arias 2013), hermaphroditic, 8–10 cm long, more or less campanulate, pale pink, pericarpel nearly 4 cm long and 1 cm wide, striate, podaria with small lanceolate scales; lanceolate scales, elongated, finished in a dark scale, the inferior flowers smaller and triangular, from 1–1.5 mm long to less than 1 mm wide, the superior flowers lanceolate and acuminate ( Fig. 2A ), increasing in size up to 5–7 mm long and 3–4 mm width, with smooth edges, dark reddish. Receptacle-tube curved above the pericarpel, pale pink, almost 5.5 cm long, supporting petaloid bracteoles, broadly lanceolate; exterior segments of the perianth oblanceolate, mucronate ( Fig. 2B ), more or less 4 cm long, pale pink; interior segments of the perianth 5.5 × 2.0 cm, oblanceolate, mucronate, pale pink; filaments around 170, anthers with longitudinal dehiscence, cream color, pale pink filaments, basified ( Fig. 2D ); whitish style, until 7.6 cm long, stigma lobes 7–8, papillate ( Fig. 2C ), ovules arranged in non-ramified follicles ( Fig. 2F ), nectarial chamber almost 1.5 cm long. Pollen grains spherical, small, with rough texture, without pores. Fruit berry-like, elliptic, 3.0– 4.5 cm long, with ribs and few spines in the areoles, green when immature and purplish-red when mature. Seeds many (more than 280) in each fruit, obovate, more than 2 mm long, brown-reddish.

Description (micromorphology): ―Spines with lignified epidermal cells, long and thin ( Fig. 2B ), middle part of the spine of 84.64 μm wide, continuous epidermal cells without fissures between the cells and smooth texture ( Fig. 2C ). Epidermis glabrous, irregular epidermal cells with smooth texture and anticlinal walls; paracytic stomata of 29.84 μm long ( Fig. 2D ). Pollen grain spherical, 52.62 μm diameter, 2131.11 μm 2 of area, without distal apertures (pores),

rough texture ( Fig. 2E ). Seed obovate, 2.16 mm long, 1.38 mm wide, brown-reddish, small micropylar-hilum region, without strophiole and dotted testa ( Fig. 3F ).

Typification:— Cactus phyllantoides was described by de Candolle (1813: 84) who cited synonym from Plukenet (1692). The latter author provided an illustration (TAB. 247) that is part of the original material for the name. Although Britton & Rose (1923) designated this name as the generic type for Nopalxochia , no formal typification of the name Cactus phyllantoides was made. No specimens in the Candolle’s collection at G, MPU, and P were found, so the Plukenet’s image appears the only extant original material. Fortunately it matches the diagnosis, and it is here designated as the lectotype of the name Cactus phyllantoides . According to the art. 9.8 of ICN (McNeill et al. 2012) we also designated an epitype as interpretative from a recent collection by O. Alcántara and A. Ponce preserved at FCME.

Vernacular names: —Nopalxóchitl,nopal,nopalito,nopalillo; Bauer(2003) wrote thatAztecs called it“Nopalxochiquezaltic”, that means “cactus with scarlet flowers”.

Ecology and distribution: — Nopalxochia phyllanthoides is distributed in the Mexican states of Veracruz (Huayacocotla Municipality), Hidalgo (Lolotla and Tenango de Doria Municipalities)and Puebla (Zacapoaxtla and Teziutlán Municipalities). This species has been poorly reported and collected, e.g., Meyrán (1962) documented it from the Sierra Norte of Puebla; Bauer (2003), Guzmán et al. (2003) and Hunt (2006) reported it as Disocactus phyllanthoides from the states of Veracruz and Puebla. Flowering time is April–June, fruiting July–October. Very restricted distribution, present in the Mexican cloud forest of Puebla, Hidalgo and Veracruz, at elevations 850–1000 m.

Conservation status: ―The species is included in the Norma Oficial Mexicana ( SEMARNAT 2010) as threatened. Also included in the IUCN Red Lists as vulnerable ( Hernández et al. 2013).

Uses: —These plants are greatly appreciated as ornamentals, because of its rareness and beauty of its flowers. Bauer (2003) consider it as one of the most beautiful and floriferous Mexican houseplants. Fruits are consumed due to their sweet flavor, and are known locally as tunitas ( Pérez-Escandón et al. 2003). Fruits are eaten by cattle, humans, birds and possibly by bats as well. Direct observations in the field by the first author supports the idea of pollination and dispersal facilitated by animals.

Phylogenetic results: —The proper mixing and convergence of the Bayesian inference was indirectly assessed with the evaluation of the estimated sample size for relevant parameters (ESS). All the ESS were of 640 or above and standard deviation between chains was 0.01; trees from both MC3 chains were mixed, and the maximum clade credibility tree was recovered with TreeAnnotator. Posterior probabilities and character support values were drawn over the MCCT as suggested by García-Sandoval (2014).

Nopalxochia phyllanthoides was recovered inside of the expanded Hylocereeae clade ( Hernández-Hernández et al. 2011) with a posterior probability of 0.99 ( Fig. 4 ), but with very low character support (below 50%). The next more inclusive clade was recovered with 95% of character support and includes species from Disocactus , Hylocereus and Selenicereus . The whole phylogenetic structure that was recovered is highly congruent with the one obtained by Hernández-Hernández et al. (2011), both in terms of topology and character support.

Figures

FIGURE 1. Habitat and macro morphology of Nopalxochia phyllanthoides. A) Epiphyte wild plant growing on Ostrya virginiana (Miller 1768: without pagination) Koch (1873: 6–7), 1.13 m tall, B) Ramified phylloclades, showing the flower base bend upwards. C) Flower in anthesis, internal segments pink, superior view. Recollected in the Municipality of Tenango de Doria, Hidalgo.

FIGURE 2. Morphological floral characters of Nopalxochia phyllanthoides. A) Longitudinal flower view, whitish filaments and yellow anthers, very long style, thin and white, yellow stigma lobes. B) Interior tepal finishing in a dark mucro. C) Seven stigma lobes, yellowish and papillate. D) Yellow anthers with longitudinal dehiscence. E) Pericarpel showing scales with the a dark and widen base. F) Ovaric chamber showing numerous white ovules.

FIGURE 3. Micro-morphological characters of Nopalxochia phyllanthoides. A) Areole with short trichomes, gloquides, base of two central spines and six radial spines, (×50). B) Apical part of a spine, continuous epidermic cells, (×900). C) Middle part of a spine, continuous epidermic cells without fissures among the cells and with smooth texture (×700). D) Glabrous epidermis, epidermic cells with smooth anticlinal walls, paracytic stomata, (×150). E) Pollen grain. F) Seed.

FIGURE 4. Phylogenetic relationships of Nopalxochia phyllanthoides. Maximum clade credibility tree for the Cactaceae family, with emphasis in PHB clade. Character support values along branches for maximum likelihood non-parametric bootstrap. Bold branches correspond with Bayesian posterior probabilities of 0.95 or above. Clade names follows Hernández-Hernández et al. (2011).