Loeselia tancitaroensis

Loeselia tancitaroensis J.M. Porter & V.W. Steinm.—TYPE: MEXICO. Michoacán: municipio de Tancítaro, foothills of Cerro Tancítaro, 1.5 km E of Tancítaro along the road to Zirimóndiro, 19º20’31”N, 102º21’10”W, clay soil, secondary scrub derived from pine-oak forest, 18 Mar 2004, J.M. Porter & V.W. Steinmann 14012 (holotype: RSA; isotypes: IEB, MEXU, SJNM, BRY).

          Herbaceous perennials from a slender, branching taproot; stems slender, 42–150 cm tall, 0.9–2.2 mm in diameter, unbranched or branched at base, erect and openly spreading, young branches green or suffused with purple, glandular-pilose with trichomes 0.2–1.2 mm long, with 5–21 stalk cells, terminating in a 1- to 4-celled, bulbous to truncate gland, trichomes often deciduous.  Lateral branches 8–34 cm long, opposite on the proximal primary stem, alternate distally.  Leaves opposite to sub-opposite, rarely whorled, sometimes becoming alternate distally, stiffly spreading to deflexed; cauline leaves shortly petiolate, the petioles 1–7 mm long, blades ovate to lanceolate, 21–60 mm long, 9–25 mm broad, acute, green, sometimes anthocyanic, the blade somewhat decurrent along the petiole, margin serrate with 5–22 teeth per side, larger leaves not persistent on flowering branches, glandular villous, trichomes much like those of the stem, 0.1–1.0 mm long, with 3–17 stalk cells, terminating in a 1- to 4-celled, bulbous to truncate gland; upper cauline leaves reduced in size distally and on flowering branches, 4–15 mm long, 1.5–7 mm broad, acuminate at base and apex, tip cuspidate, serrulate with 1–8  coarse teeth, bearing short, aristate setae, 0.2–0.5 mm long, glandular-pilose, trichomes like those of the lower leaves.  Inflorescences terminating primary and lateral branches, the branches 7–100 mm long, with 1 flower per bracteate inflorescence unit.  Bracts linear-lanceolate, 2.5–7 mm long, 0.5–1 mm broad, entire, rarely with 1 lateral lobe, terminal aristate setae to 0.5 mm long, outermost bracts herbaceous, innermost bracts white-hyaline from the margin to the central vein of the proximal 1/4 to 1/3, green and herbaceous at the distal tip, glandular puburulent, trichomes 0.07–0.5 mm long, with 2–10 stalk cells, terminating in a 1- to 4-celled, bulbous to truncate gland.  Calyx 3.5–4.5 mm long, hyaline except for the central vascular strands of each lobe and the distal lobes; lobes 2–3.5 mm long, entire, attenuate, with a terminal aristate setae 0.2–0.6 mm long, glandular-pilose throughout, trichomes 0.07–0.45 mm long, with 2–8 stalk cells, terminating in a 1- to 2-celled, bulbous gland.  Corolla bilaterally symmetrical, 9–14.6 mm long, with unequal sinuses, two short lobes and three long lobes, the lobes ovate to narrowly oblong, 4–8 mm long, 1.6–3.0 mm broad, rounded at the apex, glabrous internally, sparsely to moderately glandular-pilose externally, the trichomes 0.09–0.35 mm long, with 3–8 stalk cells, terminating in a single-celled, bulbous gland, trichomes more abundant on the vasculature and distal margin, blue-lavender, pink or rose, usually with purple flecking near the orifice of the corolla throat; tube 1.8–2.2 mm long, glabrous on both adaxial and abaxial surfaces, rarely with 1 or 2 trichomes; throat 2.2–4.8(–5.2) mm long, slightly conic, adaxially glabrous, glandular puburulent on the distal half  of the abaxial throat; filaments straight or slightly declinate, insertion equal, the free portion 6.9–11.7 mm long, glabrous; anthers 1.0–1.8 mm long, 0.4–0.7 mm wide, pollen pale blue. Pollen grains blue, 36–48 µ in diameter, spheroida; apertures pantoporate, with 22–30 pores (Fig. 2b), 3.2-4.8 µ in diameter, circular or slightly oval, often irregular, operculate, the operculum bearing 0–4 spinule like processes; exine c. 2.7 µ thick; sexine c. 1.3  thick, pertectate; tectum ca. 0.5 µ thick, suprastriate, punctate, with irregularly distributed spinule-like processes, standing 0.4–0.6 µ tall and 0.1–5.4 µ apart; punctae less than 0.5 µ in diameter, very sparsely and irregularly spaced, sometimes absent; bacula supporting tectum densely spaced, standing 0.2-0.7 µ apart, c. 0.8 µ tall, 0.4–0.5 µ thick; nexine c. 1.0 µ thick, thickest at the pore margins, to 1.4 µ. Ovary 1.0–1.5 mm long, densely glandular on the distal 1/3 to 3/4, the trichomes 0.06–0.11 mm long, with 3–5 stalk cells, terminating in a single-celled, bulbous gland; 2 ovules per carpel; style 6.6–15 mm long, filiform, stigma lobes 0.5–0.7 mm long.  Fruit ovoid, 2.2–2.7 mm long, 1.5–1.8 mm diameter; seeds 1 or 2 per locule, 1.2–2.3 mm long, 0.9–1.8 mm wide, reddish brown, ellipsoid, rarely somewhat angled, more or less flattened and lenticular, with a very narrow wing or lacking a wing entirely, funicular scar centrally located, linear, short; embryo spatulate, the cotyledons broader than the radicle and root.

            Loeselia tancitaroensis has been collected along roadsides, in ravines and canyons, on slopes, in disturbed soils and along irrigation canals.  It is associated with moist forests, dominated by pine (Pinus pseudostrobus) and oak (Qurecus spp.), at elevations of 1720–2250 m.  Flowering occurs from January to March, rarely through April, and fruiting is most common from March to early May.  The specific epithet acknowledges the mountain range, Cerro Tancitaro, on whose foothills this species is restricted.

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Loeselia tancitaroensis: Inflorescence and flowers of Loeselia tancitaroensis, scale = 5 mm

Herbaceous perennials: Loeselia tancitaroensis habit, scale = 1 cm.

trichomes: Microghaph showing glandular trichomes of the stem of Loeselia tancitaroensis, note the uni- to multicellular terminal gland; scale = 0.5 mm.

Leaves: Heteroblastic series of Loeselia tancitaroensis leaves First developed leaves (lowest) are denotes A, more distal nodes have subsequent letters. The letter L represents the terminal portion of the stem, where leaves become sub-oposite; scale = 1 cm. 

margin Photo1; Photo 2: Leaf clearings of Loeselia tancitaroensis showing details of venation, margin, and teeth; scale is indicated in each image.

Calyx: Calyx of of Loeselia tancitaroensis; scale = 1 mm.

Corolla:  Flower of Loeselia tancitaroensis, scale = 5 mm

Pollen: SEMs of Loeselia tancitaroensis pollen. Upper panel: pantoporate pollen grain; center panel: close-up of aperture; lower panel: exine surface shoeing micro-striae, spinule processes, and punctae; scale is indicated in each panel.

Ovary: Dissected ovary of Loeselia tancitaroensis, showing glandular trichomes; scale = 0.25 mm.

seeds Photo1; Photo2:  Light micrograph of Loeselia tancitaroensis seeds, scale = 1 mm (tancitSEED1.jpg). SEM micrograph of Loeselia tancitaroensis seeds showing entire seed as well as derails of seed surface micromorphology; scale is indicated on each panel (tancitSEED4.jpg).

cotyledons Photo1; Photo2: Germinating seedlings of Loeselia tancitaroensis, showing the ovate cotyledons; scale = 5 mm.

collection locations (KML file)