Heteropsis linearis, A. C. Sm., J. Arnold Arbor.

Soares, M. Lourdes, Mayo, Simon J. & Gribel, Rogério, 2013, A Preliminary Taxonomic Revision of Heteropsis (Araceae), Systematic Botany (Basel, Switzerland) 38 (4), pp. 925-974 : 948-950

6. HETEROPSIS LINEARIS A. C. Sm. ,

J. Arnold Arbor. 20: 289. 1939.

— TYPE: BRAZIL. Amazonas, Município de São Paulo de Olivenc¸a, bacia do Rio Solimões , Oct–Dec 1936, Krukoff 8781 (holotype: NY!; isotypes: BR!, K!, P!, U! fl, fr) .

Plant a scandent hemi-epiphyte; branches with internodes 3–4 cm long, 4– 7 mm diam, longitudinally striate when dried, subcylindric, with one side somewhat sulcate, dark brown when dried; axillary buds 2–3 mm long, apex rounded to truncate. Petiole 0.3–1 cm long, 1.6–3 mm diam, strongly canaliculate, margin sinuate, membranaceous; geniculum 0.9 mm long; leaf blade 12–34 cm long, 1.5–3 cm wide, linear, strongly coriaceous, dark brown on both surfaces when dried, 0.34–0.70 mm thick, margin revolute, apex acute, base strongly attenuate, midrib flattened adaxially, somewhat prominent abaxially, same color as blade, primary lateral veins and interprimary veins numerous, obscured adaxially when dried, impressed abaxially, strongly ascending towards leaf apex, joining near the margin, tertiary veins forming scattered reticulations, infra-marginal collective vein prominent, 0.75 mm distant from the margin, external marginal veins 1–2, near the collective vein. Inflorescence terminal and axillary, flowering shoot 11–25 cm long, internodes 2.5–3.4 cm long, dark brown, sulcate, lateral buds present from the first to the fifth internode; peduncle 0.8–1.4 cm long, 1–2.4 mm diam, cylindric; spathe not seen; spadix 4–7 cm long, 0.8–1 cm diam, ellipsoid, apex acuminate to obtuse, yellowish-cream, stipitate, stipe 5–7 + 3.7–4 mm. Gynoecium 2.5–4 mm long, 7–8 mm diam, truncate, apex 5–6 mm wide, stigma oblong to elliptic. Infructescence ca. 6 cm long, 3 cm diam (immature). Figures 1B , 16 .

Common Names— The following common name has been recorded for this species: tamishi tablacho ( Peru).

Habitat and Distribution— Heteropsis linearis occurs in terra firme forests and forests on seasonally flooded ground. It is known from Brazil (Amazonas, Pará, Rondônia) and Peru, occurring between 120 and 130 m alt.

Phenology— Flowering specimens have been collected between October and January and fruiting material in August and December.

Conservation Status— Using guidance from the Geocat (2012) online tool, the preliminary conservation assessment of H. linearis is least concern (LC), based on 7 localities and a 50 km cell width (auto value cell size option for area of occupancy).

Etymology— The species epithet refers to the linear leaf shape.

Notes— Heteropsis linearis is easily distinguished from the other species of the genus, even in sterile material, by the leaf blade which is narrowly linear, rigid, coriaceous and attenuate at the base. Despite this, it has often been confused with H. rigidifolia , which differs from H. linearis by the shorter (not exceeding 22 cm long) and broader (not less than 2 cm wide) leaf blade. However, the main difference between the two species lies in the size of the spadix, which is much smaller in H. rigidifolia (1.5–3 cm long). In Smith’s original description of H. linearis the flowering shoot is described as short, but our observations, based on a larger number of specimens from a wider range of locations and habitats show that it may reach 25 cm in length. Herbarium material from Peru revealed that the spathe is cream-colored and the feeder roots, known there as “tamishi tablacho”, are less used than those of “tamishi normal”, which is H. flexuosa .

Additional Specimens Examined— BRAZIL. Amazonas: Manicoré, 21 Aug 1976, Mota s.n. ( INPA 61600 fr). Pará: Óbidos , 22 Dec 1907, Ducke 9184 ( MG fr). Rondônia: Costa Marques, 24 Mar 1987, Cid et al. 8675 ( INPA ster); 1842, Claussen 17 ( P ster).

PERU. Loreto: Maynas 11 Jan. 1980, Aronson 1030 ( K, MO fl) ; 03 48 ' S 73 25 ' W, 11 Apr 1988, Vásquez & Jaramillo 10547 ( MO ster) ; Nov 1990,

Vásquez & Jaramillo 15120 (MO fl); estrada Zungarocha à Puerto Almendra, 3 Dec 1964, Dodson & Torres 3013 (MO fl).

Figures

FIG. 1. Geographical distribution of species of Heteropsis. A. H. boliviana, H. croatii, H. duckeana, and H. ecuadorensis. B. H. flexuosa, H. linearis, H. longispathacea, and H. macrophylla. Drawn by Francisca D. A. Matos.

FIG. 16. Heteropsis linearis. A. Habit. B. Venation on abaxial surface of leaf blade. C. Oblique surface view of flower. D. Frontal view of stamen. (A–D prepared from Vásquez & Jaramillo 15120 (MO)). Drawn by Felipe França.