Pilostyles boyacensis F. González & Pabón-Mora, 2014

González, Favio & Pabón-Mora, Natalia, 2014, Pilostyles boyacensis, a new species of Apodanthaceae (Cucurbitales) from Colombia, Phytotaxa 178 (2), pp. 138-145 : 139-142

Pilostyles boyacensis F. González & Pabón-Mora , sp. nov.

Type —: COLOMBIA. Department of Boyacá, Chíquiza, vereda Juan Díaz , 2415 m, 30 Nov 2013 (fl, fr), F. González 4508 (holotype HUA ; isotypes COL , NY ). Fig. 1

Species similar to Pilostyles thurberi A. Gray (1854: 326) differing for being monoecius (versus dioecious in P. thurberi ), and for the smaller (2–3 × 1.5–2.5 mm versus 3–4 × 2–4 mm in P. thurberi ), tubular flowers (versus bell shaped in P. thurberi ), nearly cleistogamous (versus the expanded petals in P. thurberi ), with purple (versus red-brown in P. thurberi ) outer and middle scales and 5 to 6 petals [versus 4(5) in P. thurberi ].

Holoparasitic, monoecious plants. Flower cushions numerous, fusiform, oriented longitudinally. Flowers gregarious; floral buds initially developed in rows of 3–10 flowers; carpellate and staminate flowers often found on each row, but the former appear to be more frequent, tubular and almost cleistogamous. Outer and middle scales free and arranged in approximately two whorls of 5 (6) organs each, imbricate, widely oblong, 0.8–1.2 × 0.6–1.0 mm, purple, adaxially and abaxially finely grooved; petals (5)6, free, bright white, oblong, 0.7–1.1 × 0.5–0.9 mm, imbricate, not expanded at anthesis; margin of scales and petals entire or sometimes very slightly crenulate. Central column pale yellowish, reaching the same length as the petals, basally surrounded by a nectarial disk in both staminate and carpellate flowers. Staminate flowers with pollen sacs irregularly arranged in 3–4 rings below a roof-like fringe of pure white papillae; vestigial ovary absent. Carpellate flowers with an inferior ovary (with respect to the petals; semi-inferior with respect to the middle scales), unilocular, ovules numerous (100+ per ovary) attached to a proliferating parietal placenta, bitegmic, semi-anatropous; stigma cupuliform, umbonate; vestigial pollen sacs absent. Fruits bacciform, depressed, subglobose, 2.5–3.5 mm in diameter, pink to white, surrounded by the persistent lower and middle floral scales; seeds numerous (80+ per fruit), pyriform.

Distribution —: The new species is known only from four populations restricted to dry thickets in the department of Boyacá, Colombia ( Fig. 3 ), above 2000 meters in elevation.

Paratypes —: COLOMBIA. Department of Boyacá, Sáchica, vereda El Espino , 2202 m, 01 Dec 2013 (fl fr), F. González 4509, 4510 ( COL, HUA, NY) ; 2200 m, 15 Dec 2013 (fl fr), F. González 4517, 4518 ( COL, HUA, NY) ; 2205 m, 01 Mar 2014 (fl fr), F. González 4519 ( COL, HUA, NY) ; 2202 m, 01 Jun 2014 (fl fr), F. González et al. 4533 ( HUA, NY) ; Soatá, Cañón del Chicamocha , 2000–2100 m, Dec 1952 (fr), found by the authors on the Dalea cuatrecasasii specimen collected by J. Hernández 665 ( COL) ; Villa de Leyva, vereda La Cañuela , 2135 m, 450 m después de la entrada al parque Gondava, 23 Mar 2014 (fl, fr), F. González et al. 4521 ( COL, HUA, NY) .

Figures

FIGURE 1. A–C. Pilostyles boyacensis (González 4508) parasitizing Dalea cuatrecasasii at proximal (A, B) and distal (C) portions of the host banches. D, E. Details of flower rows of P. boyacensis. F Mid-level of D. cuatrecasasii branches with some anthetic P. boyacensis flowers; note the narrow space left by the white petals during anthesis. G. Detail of F showing a staminate flower adjacent to a carpellate flower in the same floral row. H–K. Four different floral rows with adjacent staminate and carpellate flowers. L. Fruits, surrounded by a number of floral buds. Scale bars: 1 cm in A, C; 5 mm in B, D; 1 mm in E–G, L; 0.5 mm in H–K.

FIGURE 3. A. Distribution of Pilostyles in Colombia. B. Altitudinal ranges of the American species of Pilostyles; host and distribution data from Karsten (1856), Solm-Laubach (1878), Rose (1909), Blassingame (1968), Vattimo-Gil (1978), Yatskievych (1993), Cerros- Tlatilpa & Espejo-Serna (1998), Yatskievych & Meijer (2004), Rodríguez et al. (2008), Lárez & Calzadilla (2012), and Bellot & Renner (2014). Geographic distributions are as follows: P. thurberi, S United States and Mexico; P. mexicana, Mexico, Honduras and Guatemala; P. blanchetii, Jamaica, Cayman Islands, Costa Rica, Panama, Colombia, Venezuela, Brazil and N Argentina; and P. berteroi, Peru, Bolivia, Chile, and Argentina.