Erythroxylum plowmanianum Cogollo & Pipoly (1993:126–128) emend. Jara

Jara-Muñoz, Orlando A., 2015, A new species of Erythroxylum (Erythroxylaceae) from Colombia and emendation of Erythroxylum plowmanianum, Phytotaxa 201 (2), pp. 172-176 : 174-176

Erythroxylum plowmanianum Cogollo & Pipoly (1993:126–128) emend. Jara ( Fig. 2 ).

Similar to Erythroxylum ruizii Peyritsch (1878: 152) but differing in its cuneate foliar bases (vs. truncate to obtuse in E. ruizii ), leaves elliptic to ovate (vs. oblong to obovate in E. ruizii ), and petiole length of 2–3.5 mm (vs. 1.4–1.8 mm in E. ruizii ).

Type: — COLOMBIA. Antioquia: Municipio de San Luís, parque ecológico, Cañón del Río Claro , sector occidental, margen izquierda, subida a la Dolina, 350–375 m, A. Cogollo & R. Borja 476 (holotype, JAUM!; Isotypes, COL!, HUA!, MO!) .

Tree or shrub to 9 m tall. Branches erect-patents, 0.7–1.3 mm diam, blackish and compressed at the top, grey and frequently lichenized when older; lenticels absent. Cataphylls persistent, similar to stipules, 0.8–1.2 mm long, 0–2 at the internodes; spinules (leaf rudiment) nearly deciduous, brownish. Stipules persistent, triangular, 0.7–1.4 mm long, not striated, dark brown or glaucous and covered with wax when young, coriaceous, apex acute, two terminal setae very short and caducous. Leaves generally persistent along the branches. Petiole strongly canaliculated, 2.0– 3.5 mm long. Blade elliptic, 3.6–7.5 × 1.6–2.7 cm, firmly membranaceous, apex acuminate, base cuneate, margin entire, drying adaxially brown to greenish, abaxially pale green with no vernation lines or central panel; midrib adaxially prominulous, abaxially prominent, darkish; secondary veins 7–10, diverging 50–69° from midrib, arcuately anastomosing 2.5–4 mm from margin, prominulous on both faces; veinlets obscure. Flowers primarily in axils of leaves, also in axils of cataphylls, 1–2 per fascicle. Bracteoles triangular, 0.7–1 mm long, membranaceous, apex acuminate with a terminal setae of ca. 0.2 mm; keels patent. Pedicels pentagonal to sub-terete at the base, 1.2–3.5 mm long, gradually widening to the apex. Calyx 1–1.6 mm long, cleft ca.1/2 of its length; lobes triangular, 0.7–0.8 mm long, apex slightly acuminate to acute, with a small, pale apicule that projects on the inner face of the lobe. Petal lamina oblong-ovate, nearly concave, drying brown, 1.75–2.25 mm long, rounded to obtuse at the apex; claw broadly obovate, 1–1.25 mm long; ligule bilobed, each lobe with two well-developed auricles, the anterior auricle 0.5–0.75 long, margin entire, posterior auricle ovate, 1–1.75 mm long, margin erose. Staminal cup longer than calyx, margin crenate. Brevistylous flowers: filaments unequal in length, antisepals ca. 0.9 mm long, antipetals ca. 2.5 mm long; styles fused to 1/3 of its length from the base, ca. 1.2 mm long; stigma depressed capitate, little elongate. Longistylous flowers: filaments unequal in length, antisepals 0.5 mm long, antipetals 1.5–1.75 mm long; styles 1.8 mm long, fused 5/6 of its length from the base. Ovary ellipsoid to oblong-obovate, apex truncate, 1.5–2 × 0.7–1 mm. Drupe 8.8–9.9 × 3.3–3.6 mm, elliptic or obovate, red when mature, apex sharply acuminate; endocarp 4–sulcate, occasionally with a small empty locule.

Distribution and habitat:— E. plowmanianum has only been found in the eastern basin of the Central Cordillera of Colombia. More exactly in the regions knows as “Cañon de Rio Claro”, in the Deparment of Antioquia. This canyon has several narrow endemics species. In the early 1990s three new species were described from the same region: Cybianthus cogolloi Pipoly (1991: 262) ( Primulaceae ), Simira hirsuta C. M. Taylor (1999: 268) ( Rubiaceae ) and Pteropepon oleiferum Cogollo & Pipoly (1995: 402) ( Cucurbitaceae ). Additionally, according to Cogollo & Pipoly (1995), around 6 other new species have been detected in this region.

Discussion: —Because E. plowmanianum has connate styles and stipules that lack striations, this species belongs to section Microphyllum O.E. Schulz (1907: 114) , sensu Schulz (1907), but no species in this section is morphologically similar to E. plowmanianum . The most similar species is E. ruizii , in section Archerythroxylum O. E. Schulz (1907: 69) , which is endemic to western Ecuador. Erythroxylum ruizii shares with E. plowmanianum connate styles in longistylous flowers, a similar pattern of leaf venation and coriaceous, and triangular stipules with 2 short setae. In addition to the characters presented in the diagnosis, other characters that are useful in separating these species are: 1) fruit apex rounded in E. ruizii vs. acuminate in E. plowmanianum , 2) two conspicuous empty locules in E. ruizii fruit vs. just one, and incipient in E. plowmanianum , 3) broader leaves in E. ruizii [2.5–4.5 vs. (1.1) 1.6–2.6 cm in E. plowmanianum ].

The gross morphology of E. plowmanianum and E. cogolloi is similar. In both species, the leaves are nearly of the same size and form, and their persistent stipules are nearly 2 mm long. Additionally, both species occur sympatrically and likely share the same micro-habitat. However, they have morphological differences that were missed in the description of E. plowmanianum . Clearly, these two species are differentiated based on presence versus absence of striated stipules. Stipules in Erythroxylum plowmanianum lack striations, whereas the new species, E. cogolloi , has striations. Presence of striated stipules is a stable character used by Schulz (1907) as one of the most important characters to separate sections in Erythroxylum . Other characters that differentiate these two species are listed in Table 1.

Additional specimens examined:— COLOMBIA. Antioquia: Municipio San Luís, ecological park Cañón del Río Claro , northern sector, left side, 350–450 m, 25 October 1983, A. Cogollo, A. 814 ( COL, MO) ; Municipio San Luís, Cañón del Río Claro , north-west sector, left side, 5° 53’ N, 74° 37’, 375–600 m, 9 March 1984, A. Cogollo 1442 ( COL) ; Ibidem. 2 September 1984, A. Cogollo 1470 ( MO) .

Figures

FIGURE 2. Erythroxylum plowmanianum. A. Branches, B. Detail of fertile branch, C. Stipule in lateral view. D. Brevistile flowers without petals, E. Petal in adaxial view, F. ovary with styles and stigmas, G. Fruit in lateral view.