Barkeria palmeri (Rolfe) Schltr.
Palmer’s Barkeria
Synonyms:
Homotypic name:
Epidendrum palmeri (1893)
Barkeria chinensis subsp. palmeri (1971)
A caespitose, erect deciduous herb with an epiphytic habit that grows between 15-75 cm. Roots: flattened, gray. Stems: thin, fusiform, pedunculate (stalked), grayish-white, with 4-5 internodes, 2-25 cm. in length. Older stems are covered with scarious, papery bracts. Leaves: 2-6 linear-lanceolate, acuminate, distichous, subsucculent, present only on the newly developing growth and appressed to the stem via an articulated joint. Inflorescence: terminal, erect, frequently arching, panicle (rarely a raceme), from the new growth, on an elongated subterete, rather thin peduncle with 5-9 internodes covered by tubular bracts (scarious at anthesis), from 6.5-35 cm in length with 3-60 flowers arranged in a horizontal plane. Flowers: Attractive, resupinate, sweetly fragrant, 1.4-2.6 cm diameter spread, with the tepals straight and extended in the same plane and held over the descending lip. Color of the segments is variable in the population ranging from pure white to dark magenta with intense color saturation. Sepals are usually somewhat darker than the petals with darker venation evident. Lip is white, greyish-white or yellowish with magenta pigmentation over the raised veins and margins. Sepals are subequal, extended, lanceolate, acute-acuminate, with seven conspicuous parallel veins, incurved or flat with the margins reflexed making them concave. Petals are lanceolate, acuminate to obtuse, with five parallel vein, in the same plane as the dorsal sepal and positioned at a 45° angle to it. Both lip and column point down in their natural configuration. The lip is entire, ovate, acuminate, acute, basally cuneate, fused to the column, strongly concave with the basal margins raised and incurved, and the apex is extended or deflexed. Callus is a white, raised platform, deeply sulcate to form a fovea with three longitudinal rows of white or transparent warty or papillose veins that extend forward but do not reach the apex. The subtrigonous column is winged, short, pinkish or purple-red apically but green at the base, somewhat incurved, dorsiventrally flattened into a flabellate outline with a truncate but relatively wide apex with three teeth. The ventral surface of the column is convex and longitudinally sulcate. Anther is reddish and the same color as the apex of the column.
Barkeria palmeri is known from the Pacific Coastal Plain in the western Mexican states of Nayarit, Jalisco, Colima and Sinaloa. There are two populations in the northern and southern part of its range that are very close to the border with adjoining states so it would not be surprising to find it in Durango and Michoacán, respectively.
This species is frequently encountered throughout its range and at some of its stations could even be classified as abundant. Be that as it may, the populations are probably even larger than estimated because this plant often grows high up in the canopy of trees and only dedicated botanists who are willing to climb into the tree can observe and count them.
This Barkeria grows exclusively as a stem or twig epiphyte on trees. In the area around Boca de Tomatlan in Jalisco, this species grows in high-canopy tropical evergreen forest (jungle) dominated by high trees of Brosimum alicastrum and Cecropia obtusifolia. It seems to have an affinity for trees with smooth bark such Plumeria rubra and Ficus spp. in this habitat. It also grows in tropical deciduous forest and shrubby savanna habitats. In these biomes it can be found growing on trees of Crescentia alata, Curatella americana, Vitex mollis, Byrsonima crassifolia and Bursera spp. At higher elevations this species sometimes ventures into the tropical oak forest or semi-deciduous forest, but observations of this species there are less frequent.
1000-2000 meters above sea level. The Michoacan populations are at the higher elevation limits between 1800-2000 meters while the rest of the populations seem to grow best between 1400-1700 meters.
For most of its range in Western Mexico, this species is the only member of the Obovata section that can be found there. However, in the areas around Puerto Vallarta and Cihuatlán (both in Jalisco, Mexico), this species is sympatric with Barkeria obovata. For all intents and purposes, these two species can only be distinguished when they are blooming since they are so similar in terms of their vegetative structures. When flowers are encountered they are quite easy to determine mostly on account of their differing floral coloration. Barkeria obovata has tepals in cream or white while B. palmeri has floral segments in tones ranging from pale pink at one end of the spectrum to purple at the other. The lip outline in B. obovata is obovate and entire, whereas in B. palmeri it is usually elliptic but apically denticulate. The pigmentation of the lips is quite distinct, as well, since B. obovata has sprinkles of reddish-purple dots without any discernible pattern and yellow, verrucose, poorly-defined keels; while B. palmeri has dark lilac pigment but only on elevated veins and the conspicuously tri-keeled callus. Similarly, the anther cap in B. obovata is red but magenta in B. palmeri. The nectary in B. palmeri is decurrent to the pedicellar ovary but it is just barely visible to the trained eye of a botanist. It is not ventrally engorged or visibly swollen as in B. strophinx and B. naevosa.
This species begins blooming about a month later than the species in the Scandens and Uniflora groups at the end of November and continues for the first 6 weeks of the new calendar year.
This species is not at risk according to the Mexican government and does not merit any special protection. Barkeria palmeri has robust populations and is known from many stations throughout its range. It does not seem to interest collectors much perhaps on account of its finicky reputation for ex-situ culture.
In hybrids this species imparts floriferousness and highly branched inflorescences to hybrids. The flowers are also sweetly scented and this seems to be heritable in some of its progeny. One major negative of this species, that is also true of the other four species in the Obovata section, is that the dorsal sepal covers the lip. Thankfully this is not a dominant trait and so subsequent crosses with members of the Scandens section are useful in raising the dorsal sepal so that the lip may be more easily seen. This species is possibly the one with the most differently colored flowers of all the species in the genus. Perhaps that is why so many color variants are known including semi-alba, alba, albescens and caerulea.