Chlorospatha silverstonei Zuluaga & Munoz-Castillo, 2019

Munoz-Castillo, Allison, Guevara-Ibarra, Leonardo, Clavijo, Laura & Zuluaga, Alejandro, 2019, Two new species of Chlorospatha section Orientales (Araceae) from western Andes in Colombia, PhytoKeys 135, pp. 21-34 : 21

Chlorospatha silverstonei Zuluaga & Munoz-Castillo sp. nov. Figs 1 , 2 , 3 , 5

Type.

COLOMBIA. Valle del Cauca: municipio El Cairo, Reserva Natural de la Sociedad Civil "Cerro El Inglés”, camino al límite departamental entre Valle y Chocó. 4°44'13.3"N, 76°18'7.7"W, 2120-2230 m, 8 Oct 2017, A. Zuluaga & M.E. Cardona 1946 (holotype: CUVC!; isotypes: COL!, MO!)

Diagnosis.

Chlorospatha silverstonei can be distinguished from the other species in section Orientales by having 1-3 leaves per plant, an overall larger size (30-60 cm tall) and a small spadix (25-37.3 mm long). Additionally, it differs from C. minima sp. nov., the other species in this section from the western slopes of the Colombian Andes, in having two collective veins (vs. three in C. minima sp. nov.), the primary lateral and minor veins with scale like indument on the abaxial surface (vs. glabrous).

Terrestrial herb, 30-60 cm tall; stem decumbent, with remnants of cataphylls persisting ± intact; internodes 5.2-20.2 × 6.8-12.5 mm, drying matte, dark brown; cataphylls brownish green, (3.1 –)4.4– 8.5 cm long, acuminate at apex, drying faintly glossy, reddish brown. Leaves 1 to 3, erect-spreading; petioles 15.2 –46.8(– 52.4) cm long, free portion of the petiole 1.72-7.18 mm diam. midway, fleshy, glabrous, semiglossy, irregularly dark purple-mottled with longitudinal dark purple lines, drying dark brown to black, sheathed 2.7 –11.5(– 15.0) cm, less than 2/5 of its total length; sheath decurrent on to the petiole apex; blades broadly ovate to rounded, glabrous, conspicuously bicolor, 9.3-27.7 × 4.9 –17.7(– 21.2) cm, 1.2 to 2.3 times longer than wide, cordate at base, rarely slightly hastate, acuminate to cuspidate at apex, almost always mucronate at apex, usually slightly broader across anterior lobe than at base, distance tip to tip across posterior lobes 3.1 –13.9(– 20.5) cm, not constricted at petiole insertion; adaxial surface quilted, glossy, drying brownish green; abaxial surface reticulate, glossy, drying green to yellow-green, with several layers of cells forming a reticulum, 0.2 to 0.3 mm diam.; anterior lobe 7.2 –17.4(– 18.5) × 4.9 –17.7(– 21.2) cm, 0.8 to 1.7(-2.0) times longer than wide, 1.5 to 3.6(-4.0) times longer than posterior lobes, broader near petiole insertion, ± symmetrical; posterior lobes directed toward base, 2.1-9.6 × 1.7-8.3 cm, 0.68 to 1.45 times longer than wide, rounded to obtuse at apex, weakly broader at base, slightly inequilateral, the inner side narrower, sinus spathulate to ovate; midrib and major venation narrowly sunken adaxially, round-raised, drying ± flattened and usually darker than surface abaxially; primary lateral veins 2 to 4 per side, rarely 5-6, arising at 30°-70°, rarely 90°, straight to weakly curved towards the margin; secondary and minor veins darker than the surface, prominulous, forming a conspicuous reticulum abaxially, more visible when dried, the primary lateral and minor veins with scale-like indumentum abaxially, only visible in dried material under the microscope; collective veins 2, the outermost arising from the first and second basiscopic veins, ± parallel to margin, the innermost arising from the third basiscopic vein; basal veins coalescent into a prominent posterior rib, 1 –3(– 4) acroscopic veins, 3 –4(– 5) basiscopic veins. Inflorescences erect (all measurements made from spirit material), 1 to 4 per axil; cataphylls of the inflorescence visible outside the petiole sheath, irregularly dark purple-mottled, drying dark brown to black; peduncle 42.8-53.1 (-112.7) × 0.8-1.3 mm, held within the sheath, drying dark brown to black; spathe erect, 32.2-62.9 mm long, acuminate at apex, 4.3 –5.0(– 25.7) mm longer than spadix (1.2 to 1.7 times longer than spadix); spathe tube pale green on outer surface, rarely maroon-tinged, 8.7-23.3 × 5.0-6.3 mm, drying dark brown to black on outer surface; spathe blade maroon-tinged, with green veins on outer surface, green on inner surface, 18.7-39.7 mm long, drying dark brown or black, erect after anthesis, marcescent in fruit; spadix erect, 25.0-37.3 mm long, sessile, adnate basally to the spathe for 3.3-5.1 mm (ca. 1/3 of the length of the pistillate portion); pistillate portion light green, 8.7-16.1 × 2.5-2.9 mm; pistils coherent, ca. 1.0 mm diam.; stigma light green, sessile, ca. 0.3 mm diam.; fertile staminate portion white, 13.6-19.6 × 4.1-4.4 mm, slightly conical, rounded at apex, drying whitish brown; synandria ca. 1.1 mm diam., coherent; sterile portion white, 3.1-3.9 × 3.7-4.3 mm, wider at apex, drying whitish brown; sterile flowers with irregular borders, ca. 1.4 mm (viewed from above). Infructescence erect or pendent, brown, 18.5-32.6 × 4.8-10.3 mm, drying dark brown on outer surface; berries drying pale tan; seeds white, 6 to 20 per berry, 1.5-2.0 × 0.9-1.2 mm, ovoid to ellipsoid, longitudinally striate, minutely strophiolate, drying brown.

Etimology.

Chlorospatha silverstonei is named in honor of Dr. Phillip Silverstone-Sopkin (1939-2018), an American botanist who lived and worked in Colombia for 39 years. He was a faculty member at Universidad del Valle until 2014 and an ad Honorem professor since 2015. Additionally, he was the director of the herbarium Luis Sigifredo Espinal Tascon at the same University for 17 years. Dr. Silverstone-Sopkin collected more than 13000 botanical specimens, especially from the department of Valle del Cauca, and carried out several explorations in the region where this species was found.

Distribution and ecology.

Chlorospatha silverstonei is endemic to the western slopes of the Colombian Andes, along the border between the departments of Valle del Cauca and Chocó. It grows in cloud forests between 1900 and 2300 m. It has been collected in two natural reserves, "Cerro El Inglés” and "Alto Galapagos" ( Fig. 1 ), where it has been found widespread in the dark understory, with high humidity and, sometimes, flooded ground. This species has been recorded flowering in October and January. Information about pollination is still lacking but we observed individuals of a species of Brachonidae ( Hymenoptera ) visiting the inflorescence during female anthesis.

Conservation status.

Chlorospatha silverstonei has been found in two localities along the Serranía de los Paraguas mountain range, with an estimated extent of occurrence larger than 38000 km2. In these two localities there are several populations of this species with abundant individuals; therefore, C. silverstonei is preliminary categorized as Least Concern (LC), according to the IUCN criteria ( IUCN 2012, 2017).

Discussion.

Chlorospatha silverstonei is similar to C. minima , C. longipoda , C. hannoniae , and C. boosii , but it differs from these four species in having fewer leaves (1-3 vs. 2-14) (Table 1 ). Chlorospatha silverstonei differs from C. minima in having 1-3 leaves (vs. 2-5 in C. minima ), longer petioles, 15.2 –46.8(– 52.4) cm long (vs. 8.3-28.2 cm), that are irregularly dark purple-mottled with longitudinal dark purple lines (vs. green with darker transverse markings), blade broadly ovate to rounded (vs. broadly triangular-ovate), two collective veins (vs. three), fertile staminate portion slightly conical (vs. cylindrical), infructescence 18.5-32.6 × 4.8-10.3 mm (vs. 25.5 × 8.0 mm) and seeds 1.5-2.0 × 0.9-1.2 mm (vs. 1.2-1.5 × 0.7-0.9 mm). Finally, C. silverstonei differs from C. hannoniae and C. boosii in having cataphylls persisting ± intact (vs. cataphylls ultimately deciduous or quickly deciduous) and the absence of bulbils.

Specimens examined.

COLOMBIA. Chocó: municipio Sipí, Reserva Natural Cerro El Inglés, debajo del sitio Santicos, 4°45'22.0"N, 76°18'12.9"W, 2000 m, 17 Oct 2016, A. Zuluaga et al. 1321 (CUVC!). Valle del Cauca: municipio El Cairo, Reserva Natural Cerro El Inglés, camino desde la divisoria de aguas hasta la cabaña de investigadores, 4°44'23.9"N, 76°18'15.0"W, 2100-2200 m, 22 Jan 2016, A. Zuluaga et al. 946 (CUVC!); camino a Los Santicos, 4°45'15.5"N, 76°18'02.3"W, 2250 m, 17 Oct 2016, A. Zuluaga et al. 1305 (CUVC!); reserva natural Alto Galapagos, near to the border Chocó-Valle del Cauca, 2018, A. Zuluaga et al. (CUVC!).

Figures

Figure 1. Distribution map of Chlorospatha minima (star) and C. silverstonei (circle).

Figure 2. Inflorescence and leaf characters of Chlorospatha minima and C. silverstonei. A-I C. minima J-O C. silverstonei A inflorescence B female flowers C male flowers D sterile flowers E infructescence F adaxial blade surface, note the reticulum of cells in the peeling of abaxial surface G abaxial blade surface H primary lateral and minor veins glabrous on abaxial surface I seed J inflorescence K female flowers L male flowers M adaxial blade surface, note the layers of cells N abaxial blade surface O primary lateral and minor veins with scale-like indumentum on abaxial surface. (Photographs by Juan Felipe Ortega and the imaging laboratory at the Biology graduate program at Universidad del Valle).

Figure 3. Main morphological characters of Chlorospatha silverstonei and C. minima. A, B, E C. silverstonei C, D, F, G C. minima A adult plant B abaxial blade surface C abaxial blade surface D adult plant E cataphyll and inflorescence in post anthesis, note spathe acuminate and longer than the spadix F Inflorescence in anthesis (right) and post-anthesis (left) G shoot, showing young infructescence with deciduous spathe blade and young inflorescence.

Figure 5. Illustration of Chlorospatha silverstonei A adult plant with inflorescence B abaxial surface of leaf blade; note reticulate venation and collective veins C Inflorescence in female anthesis D Inflorescence in post-anthesis E upper view of male flowers F upper view of sterile flowers G upper view of female flowers H seed. (Drawn by Eileen Munoz from the holotype A. Zuluaga et al. 1946).