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

Synonyms:

Ledothamnus guyanensis var. nitidus A.C.Sm., Ledothamnus tatei A.C.Sm., Ledothamnus guyanensis subsp. tatei (A.C.Sm.) Maguire, Steyerm. & Luteyn, Ledothamnus tatei var. puberulus A.C.Sm., Ledothamnus steyermarkii A.C.Sm., Ledothamnus steyermarkii subsp. longisetus Maguire, Steyerm. & Luteyn, Ledothamnus stenopetalus Maguire, Steyerm. & Luteyn

Description:

Species Description - Slender, wiry or virgate, to stout, erect shrub 0.2-1 m tall; mature stems terete, glabrous; bark smooth and lustrous, or cracking reticulately; twigs terete to subterete, short-white pilose, glabrate, or very rarely glabrous. Leaves in whorls of 4, imbricate, ± appressed or more commonly spreading, elliptic to linear-elliptic, or ± oblong, 3.5-8 × 1.2-2.2(-2.5) mm, base tapering, broadly cuneate, short-decurrent, apex blunt to acute (keeled), mucronate with a deciduous, translucent, glandular or eglandular seta 0.3-0.8(-1.3) mm long, apparent margin usually minutely ciliate over entire length, also ± pectinate with few to many, deciduous, translucent, (branched) setae 0.8-2.2 mm long, these usually tipped with deciduous, minutely spherical to cylindric, reddish glands, otherwise lamina glabrous and nitid to densely puberulous, or short-pilose all over and then glabrate; petiole subterete, puberulent above, 1-2 mm long, ciliate (Fig. 2A-E). Inflorescence axillary, flowers 4-7 clustered at tips; floral bract leaf-like in all aspects; pedicel terete, striate, (10-)15-22(-50) mm long, densely short-white-pilose (glabrous), also usually densely glandular-hispid with setae often of varying lengths to 1.3 mm long (eglandular), setae also often minutely pilose at base (bifid to thinly-branched at apex); bracteoles leaf-like but 4-5 mm long. Flowers (5-)6(-7)-merous; calyx 4.5-10 mm long, lobes spreading, flat to keeled, ovate to linear-ovate, 4-9 mm long, long-acuminate, long-mucronate, densely puberulent to short-pilose all over including inner surface, also moderately to densely glandular-hispid at margin and dorsally with trichomes to 1.2(-2) mm long (eglandular); petals erect or spreading and then corolla ± campanulate (imbricate, then corolla ± campanulate-urceolate), obovate, rarely oblong-obelliptic, ca. 10-16 × (4-)5-12 mm, rounded or rarely obtuse, margin conspicuously erose (entire), scarlet to brick-red (salmon-red) when fresh, glabrous (puberulent within); stamens 5-7 mm long; filaments 2.5-5.5 mm long; anthers 2.5-3(-4) mm long; ovary glabrous to weakly puberulent; style usually verrucose at base, 2.5-3 mm long, glabrous. Capsule ovoid to globose, 6-7(-9) × 5-6 mm.

Discussion:

Ledothamnus guyanensis is characterized by leaves pectinately setose along the margins with usually glandular setae; pedicels long, short-pilose, hispid with usually glandular setae; calyx lobes nearly always puberulent on both surfaces and hispid along the margins and dorsally with usually glandular setae; and large, scarlet to brick-red petals with conspicuously erose margins. The leaves may be totally glabrous on the surfaces, but more commonly they are puberulent to (sometimes densely) short-pilose. The glandular setae of the leaf margins may be short- or long-stalked, and the actual glands may be spherical to cylindric. The setae of the pedicels are usually of varying lengths and are themselves often branched at the base or apex with thin, ± pilose hairs. Frequently, on the same herbarium sheet (= same population?) may be found separate twigs with glandular or eglandular setae, leaves glabrous to densely short-pilose, ovaries glabrous to weakly short-pilose, or setae branched to unbranched. It is interesting to note that the species, which is so widely distributed and common in the state of Bolivar, has only been collected once at Cerro Roraima (Schomburgk 963, BM, W), where it seems to have been replaced by L. sessiliflora, and once on the Chimanta Massif (Huber 9253, MYF), where it seems to be replaced by L. luteus and L. decumbens.

The collections from the two known localities in the Territorio Federal Amazonas, Cerro Marahuaca and Cerro de La Neblina, show some variation not encountered in the state of Bolívar. For example, at Marahuaca, the petal margins are not especially erose and the flowers are often nodding. At Cerro de La Neblina, normal forms of L. guyanensis are found, but there are also some with nearly glabrous sepals, nearly glabrous pedicels with few setae, and extremely long pedicels (to 4.5-5 cm long in Luteyn & Steyermark 9446 and Liesner 16040).

Several names have been synonomized under L. guyanensis because the numerous collections made in recent years have indicated that the characters used to distinguish them as distinct species are not consistent. In 1978, Maguire et al. included L. tatei under L. guyanensis as a subspecies, placing L. tatei var. puberulus in L. steyermarkii as a subspecies because they realized that presence or absence of glands on the setose hairs was not a good specific character. Furthermore, in this study I have not been able to justify the presence or absence of pubescence, presence or absence of glands on pubescence when it is present, or branching of the setose hairs as consistently useful characters at any level; branched hairs may occur on leaf margins, pedicels, or calyx lobes on all species. Both glandular and eglandular setae and glabrous and short-pilose pedicels also occur in both L. luteus and L. parviflorus. Finally, pubescence (or lack thereof) of the leaves is totally unpredictable in all species of Ledothamnus.

Ledothamnus stenopetalus, from the Meseta de Jaua, has petals more oblong and narrow (10 × 2.6-3 mm) than typical L. guyanensis, which is also found there, but I do not feel that this one character merits the basis for specific recognition.

Distribution:

Venezuela South America| Bolívar Venezuela South America| Brazil South America| Amazonas Brazil South America|