Monographs Details – Ericaceae

Monographs Details:

Authority:

Luteyn, James L., et al. 1995. Ericaceae, Part II. The Superior-Ovaried Genera (Monotropoideae, Pyroloideae, Rhododendroideae, and Vaccinioideae P.P.). Fl. Neotrop. Monogr. 66: 560. (Published by NYBG Press)

Family:

Ericaceae

Scientific Name:

Pernettya prostrata (Cav.) DC.

Synonyms:

Gaultheria myrsinoides Kunth, Gaultheria ciliata Cham. & Schltdl., Arbutus pilosa Graham, Pernettya ciliaris D.Don ex G.Don, Pernettya purpurea D.Don ex G.Don, Pernettya elliptica DC., Pernettya pentlandii DC., Pernettya prostrata var. pentlandii (DC.) Sleumer, Pernettya buxifolia M.Martens & Galeotti, Gaultheria hirsuta M.Martens & Galeotti, Pernettya parvifolia Benth., Pernettya angustata Benth., Pernettya coriacea Klotzsch, Pernettya halliana Klotzsch, Pernettya setigera Klotzsch, Pernettya pentlandii var. parvifolia (Benth.) Wedd., Pernettya robusta Wedd., Pernettya congesta Klotzsch, Pernettya oerstediana Klotzsch, Pernettya ciliaris var. alpina J.D.Sm., Gaultheria sanmartensis Rusby, Pernettya albiflora B.Fedtsch. & Basil., Pernettya densa Rusby, Pernettya schizostigma Rusby, Pernettya leucantha Linden ex Sleumer, Pernettya mexicana Camp, Pernettya obovata Camp, Pernettya tomasii Camp, Pernettya saxicola Standl. & Steyerm., Andromeda prostrata Cav., Pernettya cavanillesiana G.Don, Pernettya myrsinoides (Kunth) Zucc. ex Steud., Pernettya prostrata var. myrsinoides (Kunth) Sleumer, Pernettya pilosa (Graham) G.Don, Pernettya prostrata (Cav.) DC. var. purpurea (G. Don) Sleumer, Pernettya prostrata var. elliptica (DC.) Sleumer, Pernettya purpurea var. pentlandii (DC.) Kuntze, Gaultheria buxifolia Willd., Pernettya buxifolia M.Martens & Galeotti, Pernettya hirsuta (M.Martens & Galeotti) Camp, Pernettya pentlandii var. parvifolia (Benth.) Wedd., Pernettya purpurea var. angustata (Benth.) Kuntze, Pernettya prostrata var. angustata (Benth.) Sleumer, Gaultheria alpina Mart. ex Meisn.

Description:

Species Description - Prostrate and stoloniferous, to erect or ascending shrub, sometimes forming dense tufts or extensive mats, (0.1-)0.2-l(-3) m tall, bisexual; stems terete to subterete (sharply angled), glabrous or weakly to densely puberulous or laxly crisped pilose, and also usually moderately to densely strigose or hirsute-setose with basally swollen ferruginous, appressed or spreading eglandular and/or rarely gland-tipped hairs 0.5-3 mm long. Leaves subcoriaceous to coriaceous, narrowly to broadly elliptic, oblong, or ovate-oblong to linear-oblong, (2-)6-14(-40) × (2-)4-7(-12) mm, base rounded, obtuse, attenuate or cuneate, apex obtuse, acute or subacuminate, rarely short-mucronate or rounded, margin slightly to conspicuously thickened, usually slightly revolute, minutely crenate-serrulate with 6-12(-17) caducous teeth per side, these bristle-tipped or gland-tipped and 0.2-0.3 mm long, to hirsute-setose and eglandular to 2 mm long, blades themselves usually glabrous or rarely weakly short-pilose along the basal half of midrib above, rarely strigose beneath; midrib and secondary veins slightly impressed or raised above, raised and ± prominent beneath; petiole 1-4 mm long, often canaliculate above, glabrous to puberulous above. Flowers with pedicels (1-)4-10(-13) mm long, glabrous or puberulous (bearing short-strigose or hirsute-setose, straight or crisped, eglandular or gland-tipped hairs); bracts 5-10, ovate, ciliate, appressed, persistent, at the base and 1-6 scattered along pedicel, these (1.5-)2-4 mm long; calyx lobes membranaceous or rarely becoming fleshy after anthesis, ovate, 2-4 mm long, acuminate to acute, weakly to densely ciliate (also basally with short, gland-tipped hairs); corolla cylindric to campanulate-urceolate, (3.5-)5-6(-7) mm long, white to rose tinted when fresh, lobes 1-1.5 mm long, reflexed; stamens with filaments 1.5-3 mm long, glabrous (pilose); ovary glabrous to densely short-pubescent, style 2-4 mm long, glabrous (short-pilose in lower half). Berry subglobose, 6-16 mm diam., glabrous to densely short-pubescent, dark blue-black, rarely light purple to almost white. Chromosome number: n = 11 (Luteyn et al. 7966).

Discussion:

The berries are used in Edo. Mexico (Mexico) for making black ink (Balls 4187). On the Galapagos Islands Taylor G22 records the berry as "sweet and good." However, it is more frequent to hear the following: "said to poison mules" (Leavenworth 281, Michoacán, Mexico) or "sheep get drunk, often die, also people (children)" (Woythowski 5272, Peru). Reports vary in that some people eat the berries without ill effects (e.g., P. C. Standley, Flora of Guatemala; various others, pers. comm.) while others have been made ill (H. Pittier, Flora of Guatemala; various others, pers. comm.). Therefore, it is probably safest to avoid them.

Pernettya prostrata is characterized by an obtuse to acute (rarely mucronate-tipped) leaf apex, eglandular pubescence, glabrous filaments, and essentially Andean distribution from Mexico to northern Argentina. Because of its broad distribution in highly dissected montane regions, there is much isolation between populations and, hardly surprisingly, morphological variation. Therefore, it is not surprising that many different names have been assigned to the different populations from throughout the geographical range. I cannot see any consistent morphological variation that correlates with geography, geology, elevation, habitat, habit, etc., however, and virtually any character may appear throughout the range. Therefore, I am recognizing P. prostrata as a polymorphic species of wide distribution.

A brief discussion of some of the morphological variation is in order. Within and between adjacent populations leaf size and shape may vary considerably (see Fig. 1). In my experience, leaf size and shape may change with age of the plant. Likewise, elevational differences and exposure (to sunlight or wind) have noticeable effects on the plants, with growth being diminished and plants stunted with increasing elevation and/or exposure. The very narrow and elongate (almost linear) leaves supposedly characteristic of P. pentlandii from Bolivia also turn up at scattered localities to the north from Colombia to Mexico (where such forms were called P. buxifolia or P. mexicana). In Costa Rica (Cerro de La Muerte and Cerro Chirripo at 3300-3600 m) some plants may have leaves with distinctly and persistently mucronate tips, a feature found in P. howellii and some of the temperate Chilean-Argentinean species. While giving the plants a recognizable morphology, this character is not even consistent within a population. Furthermore, some young leaves with mucronate leaf tips lose this feature with age. Mucronate leaf tips are another unreliable character.

Stem and leaf indumentum is totally unpredictable and may range from none (glabrous) to closely appressed (strigose) to spreading (hirsute). Furthermore, the range of pubescence types may occur with any of the different leaf shapes.

In Pernettya prostrata the mature fruit color is a dark purple to blue-black. Although some apparently mature fruits are white or whitish-violet, when fully mature they will become blue-black. When in fruit, the calyx lobes of Pernettya species normally remain green and membranaceous. In some populations, however, it is often possible to find plants with some calyx lobes green and thin, while others may be blue-black and succulent.

Pernettya prostrata is closely related to P. hirta, which is known only from one small area east of Bogota, Colombia. The combination of characters given in the key is consistent, however, and gives to the species very different facies. Therefore, I have maintained them as distinct.

Pernettya prostrata is also closely related to the geographically isolated and endemic Guayana Highland species P. marginata. Here again, however, the characters given in the key are consistent and are reinforced by geographical separation.

The relationships between P. prostrata and the more temperate South American taxa from Chile and Argentina (including P. howellii from the Gal£pagos Islands) are more obscure to me because I have not studied the temperate taxa in either the herbarium or the field. One feature present in those taxa, and seemingly not in P. prostrata, is dioecy (cf. Sleumer, 1985; Cambi & Hermann, 1989).

Distribution and Ecology: Widespread from central Mexico south through Central America and the Andes to extreme NW Argentina. Found in pine-fir forest undergrowth with Arbutus, Gaultheria, and Comarostaphylis (Mexico-Guatemala), grasslands or scrub vegetation, cloud forest, subpáramo to páramo, from montane to the alpine zone, scattered or sometimes dominant and covering square kilometers on exposed slopes or in the Guatemalan highlands sometimes covering thousands of acres fide Flora of Guatemala, often on coarse rocky soil among shrubs, or over exposed banks and boulders, occasionally in wet meadows, frequently a pioneer species in new habitats created by road building, landslides, or volcanic activity at (900-) 2000-3900 (-4630) m elev. Flowering and fruiting throughout the year.