Loeselia spectabilis

Loeselia spectabilis J.M. Porter & V.W. Steinm.—TYPE: MEXICO. Michoacán: municipio de La Huacana, Sierra Las Cruces, 6.5 km (by air) SW of Los Ranchos, Cañada Las Cruces, 18°39’59”N, 102°03’46”W, ca. 650 m, tropical deciduous forest, 15 Mar 2003, V.W. Steinmann 3190 (holotype: RSA; isotypes: IEB, MEXU).

      Suffrutescent perennial; stems slender, branched at base, erect and openly spreading, 1.0–2.5 m long, young branches green, becoming whitish or gray, glandular-pilose with glandular hairs 0.3–0.8 mm long, trichomes often deciduous in age.  Leaves opposite, stiffly spreading to deflexed; cauline leaves shortly petiolate, blades lance-oblong to lanceolate, 30–48 mm long, 10–20 mm broad, broadest toward the proximal end, distal end attenuate, tip subulate, bright green, margin finely serrate toothed, spinulose tipped, finely glandular-puberulent on both surfaces, larger leaves not persistent on flowering branches; upper cauline leaves reduced in size and slightly if at all crowded distally on flowering branches, linear-lanceolate to lanceolate, 15–32 mm long, 1.5–12.0 mm broad, acuminate at apex, tip cuspidate, serrulate with 9–18  teeth, bearing short, aristate setae, along each edge; glandular puberulent.  Inflorescences paniculate, reduced cymes terminating primary and lateral branches, with 1 flower subtended by (3–)4–5  bracts, borne on few-leafed branches 24–53(–65) mm long.  Bracts linear-lanceolate, 8–12 mm long and 1.5–2.8 mm broad, denticulate and with marginal, aristate setae to 0.2 mm long, the outermost bracts chlorophyllous to chartaceous, greenish to white; inner bracts more or less white-hyaline throughout; proximal margins white to hyaline for 0.5–1.0 mm.  Calyx 3.0–3.6 mm long, hyaline along the margins of each lobe and slightly so in the sinuses, lobes 1.1–1.5 mm long, 0.7–0.9 mm broad, entire, triangular acute, with a terminal aristae, calyx tube 2.0–2.3 mm long, 1.5–1.9(–2.3) mm in diameter, glabrous.  Corolla strongly bilaterally symmetrical, 20–25 mm long, the lobes lanceolate to narrowly oblong, apex obtuse, 12–15 mm long, 2.5–4.5 mm broad, entire to denticulate, glandular-ciliate along the margin, villous on abaxial surface, glabrous on adaxial surface, very pale violet, the claw purplish; tube narrow, 7.5–9.0 mm long, glandular-pilose abaxially, nearly the entire length, glabrous adaxially; four filaments declinate, one erect, free from tube 7–8 mm above the base of tube, equally inserted at the sinuses of the corolla lobes, the free portion 8–11 mm long, glabrous; anther 1.5–1.7 mm long, 0.4–0.8 mm broad, pollen white. Pollen grains 45–51 µ in diameter, spheroidal; apertures pantoporate, with 22–28 pores, 2.8-5.3 µ in diameter, circular or slightly oval, often irregular, operculate, the operculum bearing 3–6 spinule like processes; exine c. 2.4 µ thick; sexine c. 1.0 µ thick, pertectate; tectum c. 0.5 thick, suprastriate, punctate, with irregularly distributed spinule-like processes, standing 0.2–0.4 µ tall and 0.2–3.9 µ apart; punctae less than 0.5 ?µ  in diameter, few and irregularly spaced; bacula supporting tectum densely spaced, standing c. 0.5 µ apart, c. 0.8 µ  tall, 0.3–0.5  µ thick; nexine c. 1.0 ?µ thick, thickest at the pore margins, to 2.4. Ovary pyriform, 1.2–1.5 mm tall, ca. 0.6 mm at widest point, ca. 0.5 mm at 1/2 height, glabrous throughout, 1 ovule per carpel; style 21–30 mm long, stigma lobes 0.1–0.3 mm long.  Nectary gland an undulate disk at the base of the ovary, c. 0.4 mm in diameter, c. 0.3 mm high, and c. 0.25 mm deep, bright green.  Fruit 7.0–8.5 mm long, 1.5–2.7 mm wide.  Seeds 1 per locule, 6.5–8.0 mm long, narrowly ovate to narrowly lanceolate in outline, about 5 times as long as wide, somewhat flattened in cross-section; embryo elongate, the cotyledons elongate, longer than the radical and root.

            Loeselia spectabilis has been collected on steep slopes of partially shaded ravines and canyons and on steep rocky slopes in full sun.  It is associated with tropical deciduous forest communities, associated with Albezia occidentalis, Heliotropium rufiphyllum, Ceseria corymbosum, Cocolospermum, Lygastia, Ficus, Randia, Dioscoria, Pisonia, Bursera, Acacia, Celtis, Combretum, Physodium, and Tillandsia, at elevations of 640–700 m, in the Infiernillo region of the Balsas Depression.  Flowering occurs from January to March, and fruiting is most common from late February through May.  The specific epithet, spectabilis, refers to the truly spectacular floral display of this large-flowered Loeselia.


Loeselia spectabilis: Flower of Loeselia spectabilis; scale = 2 mm.

Suffrutescent: Habit and inflorescence architecture of Loeselia spectabilis; scale = 1 cm.

Leaves:Leaf clearings of Loeselia spectabilis, illustrating leaf shape and petiole; scale = 5 mm.

blades: Leaf clearings of Loeselia spectabilis, illustrating venation, margin and teeth morphology; scale = 1 mm.

Inflorescences: Flower of Loeselia spectabilis; scale = 2 mm.

Calyx: Calyx (above) and fruit (below) of Loeselia spectabilis, note the short awn-like apex of the calyx lobes; scale = 2 mm.

Corolla: Flower of Loeselia spectabilis; scale = 2 mm.

glandular-ciliate: Margin of the corrola lobe of Loeselia spectabilis, illustrating the long, glandular trichomes; scale = 1 mm.

Pollen: SEM micrograph of pollen of Loeselia spectabilis; upper panel shows the entire pollen grain; lower panel is a close-up showing the aperture, exine micro-striae, and spinule processes; scale is provided for each panel.

Ovary: Micrograph of the dissected ovary of Loeselia spectabilis; scale = 0.5 mm.

Fruit: Calyx (above) and fruit (below) of Loeselia spectabilis, note the dehiscence pattern of fruit, which extends only about half the length of the capsule; scale = 2 mm.

Seeds: Micrographs of the seed of Loeselia spectabilis; upper left: micrograph if seed, note the embryo shape; upper right: SEM micrograph of whole seed, note the funicular scar (hylem) on the lower seed; lower: close-up SEM images of the seed coat, showing the microsculpture of the testa; scale indicated on the images.

cotyledons: Germinating seedling of Loeselia spectabilis, note the lanceolate cotyledons; scale = 5 mm.

Infiernillo region: (KML file)