Camaridium perezianum Rodr.

Rodríguez-Martínez, Lizeth & Blanco, Mario A., 2015, A new species of Camaridium (Orchidaceae: Maxillariinae) from the cloud forests of Colombia, Phytotaxa 222 (1), pp. 61-66 : 62-65

Camaridium perezianum Rodr. -Martínez & M.A. Blanco, sp. nov. ( Figs. 1 , 2 )

Similar to Camaridium nutantiflorum Schlechter (1918: 417 − 418) , but differs from that species by its subrhombic, apically rounded labellum and by its slightly trifid, basally papillose callus.

Type: — COLOMBIA. Valle del Cauca: Municipio de Dagua, El Queremal, remnant cloud forest, 1850 m, 21 September 2012, Rodríguez & Rincón 019 (holotype: VALLE!).

Plant an epiphyte, up to 1 m tall. Roots not seen. Stems erect, sympodial, scarcely branched; each sympodial unit up to 55 cm long, with a terminal pseudobulb, with 1–2 branches arising from the nodes just before the pseudobulb. Pseudobulb elliptic to ovate, flattened, 5.0–6.0 × 4.0–5.0 cm, partly covered by the bases of leaves, with one apical leaf. Leaves distichous, completely covering the stem (including most of the pseudobulb), dimorphic; the 11–14 proximal leaves of each sympodial unit oblong, retuse, conduplicate, falcate in profile, 3.4–5.7 × 1.2–2.0 cm, green, with a transverse abscission line at the middle, the blade caducous upon maturity of the sympodial unit; the 8–10 distal leaves of each sympodial unit pseudopetiolate (pseudopetiole comprised by the extended, conduplicate leaf sheath); 19.2–34.2 cm long; the sheath strongly conduplicate, 4.3–5.4 cm long; the blade lorate, suboblong, slightly wider above the middle, acute to retuse, basally attenuate, 15.2–29.5 × 1.9–3.5 cm; the leaf apical on the pseudobulb similar to the distal leaves, but without a sheath. Inflorescences single-flowered, produced from the axils of the short, proximal leaves during the early stages of elongation of the sympodial unit, when the distal large leaves and pseudobulb have not yet expanded; 5–9 inflorescences produced per shoot, with flowers opening in a rapid succession. Peduncle 5.2 cm long, with 3 distichous bracts (including the floral bract); only the last two emerging from the subtending short-leaf sheath. Floral bract ovate, acute, cucullate, sheathing the pedicel and ovary, 2.5–2.7 × 1.5 cm, its tip overlapping with the base of the dorsal sepal. Pedicel plus ovary cylindrical, smooth, 1.38 cm long, 5 mm in diameter. Flowers resupinate; sepals and petals yellow adaxially, pale yellow abaxially; the sepals lightly spotted with reddish purple at the base; labellum cream with transverse purple spots, the papillae yellow with purple apices; column cream, basally flushed with purple. Sepals long-lanceolate, suboblong, acute; the dorsal sepal 30–35 × 8–9 mm, 9-veined; the lateral sepals 30–35 × 9 mm, 8-veined. Petals long-lanceolate, suboblong, acute, 25–30 × 8–9 mm, 6-veined. Labellum subrhombic, 3-lobed, shortunguiculate, minutely erose on the distal half, 11 × 12 mm; lateral lobes triangular, subacute, apically rounded, erect; midlobe subquadrate to widely rounded, apically subtruncate to widely rounded, straight, slightly larger than lateral lobes; disc 6–7 × 3 mm, papillate at base, apically projected as a ligulate, minutely trifid callus, whose apex ends at the base of the midlobe. Column hemicylindrical, arcuate, apically truncate, 1.3 × 0.4 cm, basally provided with a shortly projecting (0.6 cm) foot. Anther operculum not seen. Pollinia ovoid, flattened. Fruit not seen.

Distribution and ecology:— Camaridium perezianum is known so far from the remnant cloud forest on the western side of the western range of the Andes, municipality of Dagua, corregimiento of El Queremal, department of Valle del Cauca, Colombia. It was observed growing as an epiphyte, in fragmented cloud forest at 1800–1900 m elevation. Five individual plants were seen, and flowering was observed in July and September.

Etymology: —Named after Oscar Alejandro Pérez Escobar, currently a graduate student at the Ludwig-Maximilians University (Munich, Germany), who has contributed to the knowledge of the Colombian orchid flora and who has constantly motivated the orchid taxonomy studies of the first author for several years.

Discussion:— Camaridium perezianum belongs in a small group of species that include C. darienense ( Atwood 1998: 254 − 257) Szlach. & Sitko in Szlachetko et al. (2012: 25, as “ darienensis ”), C. ampliflorum ( Schweinfurth 1940: 188) Blanco (2007: 519) , C. campanulatum ( Schweinfurth 1938: 94 − 96) Blanco (2007: 520) , C. carinulatum ( Reichenbach 1877: 6) Blanco (2008: 15) , and C. nutantiflorum Schltr. The last five species form a clade with weak (70%) bootstrap support in Whitten et al.’s (2007) phylogenetic analysis of subtribe Maxillariinae ( C. darienense was not sampled, but is morphologically most similar to C. carinulatum ).

The six species in this group (here defined as the “ Camaridium carinulatum alliance”, which ranges from Costa Rica to Peru) share the same growth habit; juvenile plants have caespitose pseudobulbs, but when mature they produce elongate, erect sympodial units. Each sympodial unit has many short, falcate (curved outward) leaves at the base, followed by several larger, ligulate leaves and a terminal pseudobulb with one or two terminal leaves. The single-flowered inflorescences are always borne from the axils of the short, falcate leaves during the early development of the sympodial unit. Atwood (1989; also in Atwood & Mora de Retana 1999) described these plants as having “half-lyre shaped foliaceous bracts subtending the inflorescences”, in reference to the falcate short leaves of the young shoots. The young sympodial units that bear flowers are sometimes mistakenly described in herbarium labels as racemose inflorescences. The blades of the short leaves are shed soon after anthesis. After maturation of the pseudobulb, a new elongate sympodial unit is produced from the axil of one of the large leaves, eventually producing a branch composed of several sympodial units, that is apically ascending but becomes hanging because of its own weight. The pseudobulb at the base of the branch can produce other pseudobulbs at its base that repeat these growth pattern, and thus older plants often display groups of branches. Roots are produced only by the pseudobulbs at the base of each branch (the only ones in close contact with the substrate). A similar growth and flowering habit is displayed by other species of Camaridium (e.g., C. ctenostachys ( Reichenbach 1870: 39) Schlechter (1923: 238)) , but plants of these other taxa are often less robust, and the short leaves at the proximal part of each sympodial unit are never falcate (“half-lyre shaped”).

As is common in the genus Camaridium , the flowers of species in the C. carinulatum alliance rarely open widely. The labellum is 3-lobate, approximately as wide as long when flattened, and the lateral lobes are relatively large, triangular, and obliquely to perpendicularly oriented relative to the midlobe (however, the labellum of C. campanulatum is relatively narrow and has short lateral lobes that are parallel to the midlobe; see Figs. 14 D–E and 15 A–B of Atwood & Mora de Retana 1999). The labellum in these species is also spotted, and has papillae at the base in some species (e.g., C. ampliflorum , C. bradeorum and C. perezianum ). The flowers do not produce nectar nor any other obvious reward for pollinators.

Camaridium perezianum is superficially most similar to C. nutantiflorum (especially because of the yellowish sepals and petals), but differs from that species by the larger flowers, subrhombic (vs. distinctly 3-lobed), apically rounded (vs. acute) labellum, the ligulate, minutely trifid (vs. subquadrate, widely obtuse or longitudinally split when flattened), basally papillose (vs. smooth) callus, and by the longer column (13 mm vs. 5 mm long). The labellum of C. perezianum is most similar to that of both C. ampliflorum and C. carinulatum , in that it has dark, transverse bars (in life), an acute midlobe, a basal field of papillae, and a ligulate, minutely trifid callus. However, the labellum lobes of C. perezianum are much shorter and set almost perpendicular to the midlobe, giving the labellum a subrhombic shape.

Both Schlechter (1918; see also Mansfeld 1931: t. 68, Nr. 271) and Atwood (1989, 2003; also in Atwood & Mora de Retana 1999: Fig. 15A, as the homotypic synonym Maxillaria umbratilis Williams 1941: 425 ) described and illustrated the callus of Camaridium nutantiflorum as having and inverted V-shape (i.e., bifid). However, several herbarium specimens of this species show an apically subquadrate, widely obtuse callus (M.A. Blanco, personal observation), just like the one shown in Atwood’s own drawing of a rehydrated flower from the isotype of C. vinosum Schlechter (1923: 240 ; a synonym of C. nutantiflorum ) at AMES (attached to that specimen), which could be described as “non-inverted V shaped”. Examination of several living flowers and one liquid-preserved flower (Bogarín et al. 5598, JBL) show that the callus of C. nutantiflorum is a triangular, obtuse, thick (ca. 2 mm tall) structure, slightly thicker at the base. These plants do not differ in any other significant trait from the ones with an apparently bifid callus. Therefore, the apical notch of the callus seen by Schlechter and Atwood is most likely an artifact caused by longitudinal splitting when the labellum of this species is rehydrated and/or flattened. Atwood & Mora de Retana (1999: 80) commented that the callus of C. nutantiflorum “is more V-shaped in front than shown by his [Schlechter’s] drawing, but when pressed the tips of the V tend to point forward. A rehydrated flower from Brenes 234 [the type of C. vinosum ] shows the same type of callus.” The wording of Atwood & Mora de Retana (1999) is somewhat confusing in the absence of comparative illustrations, but they appeared to have noticed the inconsistency.

The following key can be used to identify the six currently known species of the Camaridium carinulatum alliance.

Figures

FIGURE 1. Camaridium perezianum. A. Plant habit. B. Flower, front view. C. Flower, oblique view. D. Dissected perianth. E. Column and detached labellum, side view. F. Extended labellum. G. Column, ventral view. Drawn by L. Rodríguez-Martínez from the holotype.

FIGURE 2. Camaridium perezianum in life, type collection. A. Habit. B. Flower, front view. C. Flower, oblique view. D. Labellum, extended. E. Detail of labellum and column, front view. Photos by C. Rincón-Useche and L. Rodríguez-Martínez.