Critoniopsis tausae H. Rob. & S.C. Keeley, 2015

Robinson, Harold & Keeley, Sterling C., 2015, A refined concept of the Critoniopsis bogotana species group in Colombia with two new species (Vernonieae, Asteraceae), PhytoKeys 48, pp. 85-95 : 89-90

Critoniopsis tausae H. Rob. & S.C. Keeley sp. nov.

Type.

COLOMBIA: Cundinamarca: Mun. de Tausa, 8.4 km from fork in road to San Cayetano and Los Pached. On road to San Cayetano, about 2 km above Boca de Monte, 12 km below summit of Paramo Leguma Sec. Elev. 3150 m, 30 Dec, 1984, S.C. Keeley with J.E. Keeley 4543 (holotype US, isotypes COL, K).

Description.

Shrubs or small trees up to 6 meters tall. Stems terete, dark brown, covered with grayish indument of short irregularly-shaped trichomes; internodes 0.5-1.0 cm long. Leaves alternate; petioles mostly 1.0-1.5 cm long; blades subcoriaceous, elliptical to broadly ovate-elliptical, 7-11 cm long, 2.7-4.3(-6.5) cm broad, base usually acute, without decurrence onto petiole, broad-leaved specimen (Keeley 4544) with obtuse to rounded base, margins mostly entire or with few teeth distally, broad-leaved specimen with margins distinctly serrate distally, apex acute, with little or no acumination, adaxial surface essentially glabrous, veinlets variously slightly incised to slightly prominulous, abaxial surface with prominent primary and secondary veins, tertiary veins prominulous and quaternary veinlets obscure to slightly prominulous, secondary veins ca. 8 on each half, mostly spreading at ca. 45°, arching, lower secondary veins more widely spreading in broad-leaved specimen (Keeley 4544), surface covered with dense appressed grayish pubescence, individual trichomes with short stem and stiff spreading stellate arms. Inflorescence terminal on leafy branches, densely pyramidally paniculate with corymbiform branches, mostly 9-12 cm high and wide. Branches grooved, covered with dense whitish tomentum, heads sessile or on short peduncles 1-3 mm long. Heads cylindrical, at anthesis ca. 12 mm long and 4 mm wide, with ca. 35 involucral bracts in ca. 7 series, ca. 4 rows of basal bracts densely imbricated, broadly ovate, ca. 0.5-3.5 mm long, 1.5-2.5 mm wide, with scarious lateral margins, persistent and widely spreading with age; inner bracts in ca. 3 series, oblong, 5-7 mm long, 1.5-2.2 mm wide, with narrowly recurved lower margins, with flattened rounded, dark and membranous tips, highly deciduous with age, all but basalmost bracts glabrous on outer surface; receptacle glabrous, flat. Florets 5 in a head; corollas white, funnelform, ca. 8 mm long, basal tube ca. 4 mm long, throat ca. 1.5 mm long, lobes ca. 2.6 mm long, linear-lanceolate; outer surface of upper tube, lower throat and lobes with minute monoseriate trichomes, a few glandular dots at tips of lobes; anther thecae purple, ca. 2.5 mm long, bases with short obtuse sterile margin, apical appendages ca. 0.5 mm long, oblong-ovate; style base broadened, shortly conical. Achenes light brown, ca. 4 mm long, without evident glands or setulae on surface, with longitudinal striae; Pappus white, ca. 5 mm long, inner pappus of ca. 40 capillary bristles, flattened beyond middle and slightly broadened at tips, outer pappus a series of lanceolate squamae 0.5-1.7 mm long.

Additional specimens examined.

COLOMBIA: Cundimamarca: Prov. Ubaté; Mun. Tausa, 8.4 km from fork in road to San Cayetano and Los Pachos, on road to San Cayetano, about 2 km above Boca de Monte, 12 km below summit of Paramo Legune Sec. Elev. 3150 m. Plants 6 m tall, 7-10 flower heads, revolute corolla lobes white with purple anthers; 30 Dec. 1984; S.C. Keeley with J.E. Keeley 4544 (US); Mun. de Tausa, 10.9 km from fork in road to San Cayetano; Elev. 3000 m, 20 Dec. 1984; S.C. Keeley with J.E. Keeley 4545, 4546, 4547, 4548, 4549 (US); individuals about 6 m tall’ population seen about 10-12 individuals. Tausa is at 5°11'47"N; 73°53'15"W.

The specimens of the species were initially left unidentified because of the comparative lack of prominence of the tertiary and quaternary veins and the comparatively even surface of the pubescence on the abaxial surfaces of the leaves. In Critoniopsis bogotana , the venation of the abaxial leaf surfaces is distinctly reticulated, and the tomentum is mealy in appearance. Examination of the trichomes under the light microscope is sufficient to show the profound difference in the trichome shape, shown here in SEM photos. The stellate form is consistent in every specimen sampled from what are evidently members of at least two separate populations.

A problem that seemed of importance when the specimens were first studied, was the striking difference in the leaf shape of one of the collections (Keeley 4544). This broad-leaved form had more obtuse to rounded bases of the leaf blades, more broadly ovate blades, and distinctly multiple serrate distal margins on the leaves. This is seen here as a difference within the species. It is reminiscent of the leaves that often arise on sprouts or sucker shoots from stumps of felled trees, and is not regarded here as worthy of any taxonomic distinction.