Monographs Details: Disterigma ollacheum Pedraza
Authority: Pedraza-Peñalosa, Paola. 2010. (Ericaceae, Vaccinieae). Fl. Neotrop. Monogr. 108: 1-126. (Published by NYBG Press)
Family:Ericaceae
Description:Latin Diagnosis - Species nova foliis crassis, in sicco rugosis, ellipticis vel raro suborbicularibus, in apice obtusis, prominenter apiculatis, floribus maximam partem solitariis, pedicello 1.5–4.5 mm longo, manifesto vel minimum ex parte per bracteas imbricatas non omnino occulto, bracteolis apicalibus glabris, floribus 5-meris, aestivatione calycis valvata, tubo calycis acuti-angulato, sinubus acutis, corolla pallide viridi vel cremea incrassato-carnosa urceolata, adaxialiter glabra, thecis tubulisque papillosis, fructibus purpuratis, embryone seminis alba distincta.

Species Description - Shrubs growing over rock outcrops or inside rock cracks, prostrate and decumbent, or erect, to 0.6 m tall. Young branchlets ridged, ± smooth, glabrate or puberulous, the hairs white, minute, eglandular and glandular, the mature branches glabrous. Leaves 0–4 per cm, spirally arranged, diffuse; petiole 1.1–2.6 mm long, glabrate, the hairs eglandular and glandular; lamina succulent and drying wrinkled, elliptic or rarely suborbicular, (0.9–)1.3–2.5 × (0.5–)0.7–1.2 cm, basally obtuse, marginally entire, apically ciliolate or ciliate with eglandular hairs (especially in young leaves), apically obtuse and prominently apiculate, adaxially glabrous or glabrate in young leaves with eglandular and glandular hairs, abaxially glabrate with glandular hairs, the venation obscure or hyphodromous on both sides, the midvein adaxially impressed and abaxially raised. Axillary solitary flowers and sometimes 2-flowered fascicles; bracts 3–6, chartaceous, ovate, 0.8–2 × 1–2 mm, marginally ciliolate with minute and few eglandular and glandular hairs, apically obtuse, abaxially glabrous; pedicel 1.5–4.5 mm long, evident or at least with a portion of it not completely obscured by overlapping bracts, glabrous or glabrate with eglandular and glandular hairs; differentiated apical bracteoles green, 2, distinct, chartaceous, enveloping the base of the calyx tube or the entire calyx tube, covering 36– 50% of calyx, transverse-elliptic, 1.8–2.7 × 3–4 mm, marginally ciliolate with eglandular hairs or minute glandular hairs, apically truncate or sometimes obtuse, the surface smooth, abaxially and adaxially glabrous. Flowers 5-merous. Calyx aestivation valvate, campanulate, 4.2–5.5 mm long; tube sharply angled with the angles sometimes looking like very small wings in herbarium specimens, 1.7–2.5(–3) mm long, abaxially puberulous with eglandular or glandular hairs; limb (2.3–)2.5–3 mm long, abaxially puberulous with eglandular or glandular hairs, adaxially glabrous; lobes triangular, 1.3–1.8 × 1.5–3 mm, marginally eciliate, apically acute; sinuses acute (V-shaped). Corolla light green or cream-colored, thick-fleshy, very hard and leathery in both fresh and dry material, bistratose, urceolate, (6.6–)7–8.5(–9) mm long, 5.3–6 mm diam., 3.3–4 mm wide at throat, abaxially and adaxially glabrous; lobes 1.1–1.5 × 1.1–1.7 mm, apically acute, adaxially rugose. Stamens 10, 5.1–6.2 mm long, included; filaments distinct, straight, ± linear with parallel sides, 2.9–3.5 mm long, abaxially glabrous, adaxially puberulous distally; anthers distinct, papillae on both thecae and tubules; thecae 1.6–2.2 mm long, without basal appendages; tubules 2, distinct, 1.7–2 mm long, dehiscing introrsely by longitudinal slits, 0.8–1.2 mm long. Ovary 5-locular; style 6.7–7.7 mm long, included. Berry purple, ± spherical, 6–8.3 mm diam., the persistent calyx lobes erect or spreading, becoming succulent (at least at base), same color as mature berry; embryo white.

Distribution and Ecology - Disterigma ollacheum is known from southern Peru, around Ollachea (Puno) and Tabina, a locality that probably belongs to the same province (Fig. 35). The species has a wide altitudinal range of (1800–)2100–3600 m, growing epilitic in puna and montane vegetation (Fig. 34A). Flowering in May, Jun and Aug; fruiting in May. The flowers are visited by bumblebees and hummingbirds (Boeke 2983). Additionally, an intricate ant nest (ant collection P. Pedraza 1534, undetermined) was found in the root system of this plant in the narrow layer between the rock and the humus.

Discussion:

Disterigma ollacheum (Figs. 33, 34A,B) is characterized by having succulent leaves that are wrinkled when dry, the leaf lamina elliptic or rarely suborbicular and with an apex obtuse and prominently apiculate; relatively long and evident pedicels, or at least with a portion of the pedicle not completely obscured by overlapping bracts; 5-merous flowers; sharply angled calyx tube that sometimes looks shortly winged in herbarium specimens; a light green or cream-colored, leathery, urceolate, and adaxially glabrous corolla; papillae on both thecae and tubules; and purple berries with white embryos. Disterigma ollacheum has leaves similar in size and shape to those of D. ovatum, as well as flowers solitary and 5-merous. Nevertheless, these two species can be easily separated with careful observations; their major differences are summarized in Table X.

Distribution:Peru South America| Puno Peru South America|

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