Serpocaulon tayronae D.Sanín, 2015

Sanín, David, 2015, Serpocaulon tayronae (Polypodiaceae), a new species from the Sierra Nevada de Santa Marta, Colombia, Phytotaxa 213 (3), pp. 243-252 : 245-249

Serpocaulon tayronae D.Sanín , sp. nov. ( Figs. 1 , 2 )

Serpocaulon tayronae is similar to S. eleutherophlebium ( Fée 1852: 255) Smith et al. (2006) , S. obscurinervium (Sanín 2014: 129) and S. patentissimum (Mett. ex Kuhn 1869: 134) Smith et al. (2006) by sharing long-creeping rhizomes with patent concolorous scales. However, S. tayronae differs from the first two by the whitish orange, light-coloured scales with smaller size 3−(4.5)−5 × 1−(1.5)− 2 mm long (vs. dark brown, 3.5−(5.1)− 7.1 mm long in S. eleutherophlebium and dark orange, 5.2−(6.3)− 8.5 mm long in S. obscurinervium ), the pectinate shape of the laminae (vs. pinnatisect in both species), from S. patentissimum by its linear-lanceolate rhizome scales with bigger size 3−(4.5)−5 × 1−(1.5)− 2 mm long (vs. triangular to ovate-lanceolate, 0.6−(1.1)−1.7 × 0.2−(0.4)− 0.6 mm long) and the ascending, long-attenuate segments (vs. parallel and cuneate segments).

Type: — COLOMBIA. Magdalena: Santa Marta, Sierra Nevada de Santa Marta, Las Nubes, 1524 m, 1898−1901, H.H. Smith 1025 (holotype BR!, isotypes BP!, CM!, DAO!, E!, ISC!, MICH!, MPU!, NY!, TEX!).

Plants epiphytic, rhizomes 1−(2)− 5 mm in diameter, long creeping, yellowish to brown, densely scaly. Phyllopodia spaced 2−(3)− 10 cm. Scales 3−(4.5)−5 × 1−(1.5)− 2 mm, basifixed, peltate, with the base appressed rounded and the apex patent acuminated, linear-lanceolate, numerous and dense along the rhizome, concolorous, orange, iridescent, the margins entire. Petiole 4−(11)− 17 cm, subterete, stramineous, proximally narrowly winged, the wings increasing in width distally. Lamina 15−(21)−33 × 4−(6)− 11 cm, pectinate to narrowly pinnatisect proximally, narrowly lanceolate, the base cuneate and reduced, the apex attenuate, gradually tapering to a caudate apical segment. Segments 18−(27)−39 pairs, membranaceous to papyraceous, middle, basal and apical segments decurrent, ascending and long-attenuate. Middle segments 2−(3)−5 × 0.3−(0.4)− 0.8 cm. Veins free, 7−(8)−9 along the middle segment, sterile and fertile veinlets conspicuous. Scales absent from the segments. Trichomes of the blade and rachis sparse, 7−9 celled, 0.5−0.8 mm long, terete, catenate and hyaline. Sori 2−(6)−8 along the segment and one row between the costa and margin. Sporangia 250−275 × 215−225 μm long, glabrous, annuli 9−(11)−13 cells long. Spores 45−47 × 30−33.5 μm long, leasurae 15−17 μm long, straight, ellipsoid, sub-ellipsoid to globular plane-convex, spores with dense rounded verrucae, verruca 2−4 × 1−3 μm, regular in size, apex rounded and evenly distributed.

Distribution and habitat: — This species is registered from the lower montane wet forest of the Sierra Nevada de

Santa Marta ( Fig. 3 ) at 1524 m in Las Nubes, Magdalena Department. This location is above threshold of 800−1000

m from where Hernández-Camacho et al. (1992) suggested that the rate of endemism increases significantly in the region. After having checked the Colombian fern material the principal herbaria without finding more material of this species, it is possible that Serpocaulon tayronae represents an endemic for this region.

Etymology:— The specific epithet refers to the native people of the Sierra Nevada de Santa Marta and their legacy, the Tayrona Culture.

Notes:— Some species of the Polypodium plesiosorum ( Kunze 1844: 313) and P. dulce ( Poiret 1804: 523) complexes (especially P. tenuifolium (Humb. & Bonpl. ex Willd. 1810: 185)) , resemble Serpocaulon tayronae by the whitish or light-coloured rhizome scales and the segments of the lamina ascending, with free veins. However, S. tayronae differs from any species of Polypodium by long-creeping rhizomes with clathrate rhizome scales rounded at the base, subterete petiole and the pectinate lamina (vs. short creeping rhizome with non-clathrate scales and invaginated at the base with somewhat overlapping basal lobes ( Tejero-Díez 2005, Smith et al. 2006), sulcate petiole and pinnatisect laminae ( Tejero-Díez & Pacheco 2004a, b, Tejero-Díez et al., 2010)) ( Figs. 4 , 5 ). It further differs from species belonging to the P. dulce group by rachises glabrous adaxially and glabrous sporangia (vs. rachises puberulent adaxially and sporangia typically setulose; Moran 1995).

Interestingly, Serpocaulon tayronae has segments of the lamina with free veins ( Figs. 1C, D ) as is the case in other Serpocaulon species, such as S. eleutherophlebium , S. obscurinervium and S. patentissimum (Sanín 2014, Sanín unpublished data). However, Smith et al. (2006) described as a diagnostic character of Serpocaulon the presence of regularly anastomosing veins (goniophlebioid), chevron-shaped areoles and each with a single, free, included vein. It was suggested by Tejero-Díez et al. (2010) that the taxa of the southern hemisphere in the neotropics have exclusively anastomosing veins ( Serpocaulon and Synammia ), and the species of the northern hemisphere ( Polypodium vulgare complex) and ( P. dulce complex) have open venation patterns. The newly described “ S. tayronae ” and other species with pinnatisect laminae of the northern Andes ( S. eleutherophlebium , S. obscurinervium and S. patentissimum ) show that the morphological genus concept of Serpocaulon should include both types of venation: anastomosing and free veins.

Figures

FIGURE 1. Serpocaulon tayronae.A. Habit. B. Rhizome scale. C. Basiscopic sterile part of the segment. D.Acroscopic fertile part of the segment. E. Lamina trichome.All from Smith 1025 (BR).

FIGURE 2. Serpocaulon tayronae.A. Spore in proximal view. B. Spore in ventral view. C. Verrucae detail. D. Esporangium. E. Clathrate rhizome scale. F. Margin of the segment.All from Smith 1025 (BR).

FIGURE 3. Location of the collecting sites of H.H. Smith. A. Location of the Sierra Nevada de Santa Marta, Colombia. B. Study area of Smith’s expedition; circles: sites of interest (Simón Bolivar and Cristóbal Colón peaks at 5775 m, and Santa Marta City); stars: most important collecting sites and location of the type locality, Las Nubes.

FIGURE 4. Comparison between the rhizome scales of similarspecies of Polypodium andSerpocaulon.A.Serpocaulon eleutherophlebium (from Rodríguez et al 5970, COL). B. S. tayronae (from the type Smith 1025, BR), C. S. obscurinervium (from the type Hagemann & Leist 1898 (PSO). D. S. patentissimum (from Arbeláez 325, HUA). E. Polypodium colpodes var. oligomerum (from Tonduz 8804, BR). F. P. tenuifolium (from Wright 1030, NHN). G. P. dulce (from Tückheim 4047, BR). H. P. flagellare (from the type Biolley 2671, BR). I. P. plesiosorum (from Pringle 3352, BR). Scale bar: A–D (0.5 mm), E–I (1 mm).

FIGURE 5. Silhouettes of species resembling Serpocaulon tayronae. A S. eleutherophlebium (from Jaramillo-Mejía 6451, CAUP), B. S. obscurinervium (from the type Hagemann & Leist 1898 (PSO). C. S. patentissimum (from Arbeláez 325, HUA). D. Polypodium colpodes var. oligomerum (from Tonduz 8804, BR). E. S. tayronae (from the type Smith 1025, BR). F. P. tenuifolium (from Wright 1030, NHN). G. P. dulce (from Tückheim 4047, BR). H. P flagellare (from the type Biolley 2671, BR). I. P. plesiosorum (from Pringle 3352, BR). Scale bar: 10 cm.