Serpocaulon rex Schwartsb. & A.R.Sm., J.Bot. Res. Inst.

Kessler, Michael, Smith, Alan R., Øllgaard, Benjamin, Matos, Fernando B. & Moran, Robbin C., 2023, Prodromus of a fern flora of Bolivia. XLII. Update I., Phytotaxa 630 (3), pp. 183-210 : 200

Serpocaulon rex Schwartsb. & A.R.Sm., J.Bot. Res. Inst. Texas 7(1): 86–88, f. 1. 2013.

Range:— Ecuador to Bolivia (PA, SC), Brazil, and Paraguay ( Sanín et al. 2023). Schwartsburd & Smith (2013) described this species as a narrow endemic to the Atlantic rain forest and seasonal semideciduous forest from Brazil. Sanín et al. (2019 a, 2023) extended this distribution to Goias and Mato Grosso do Sul states, as predicted ( Schwartsburd & Smith 2013). Here, its range is now known still wider in Brazil, as well as in neighboring countries.

Ecology:— Rare, epiphytic in lowland swampy ecosystems, along the margins of streams of seasonal forests, at 0‒ 700 m.

Notes:— Serpocaulon rex most resembles S. attenuatum and S. triseriale , which also have thick rhizomes (6‒20 mm) with abundant pubescent roots, lanceolate rhizomes scales with patent apex, and impressed veins. However, S. rex differs from S. attenuatum by the long-creeping rhizome (vs. short-creeping), pinnate blades (vs. proximally pinnate and distally pinnatisect), and more rows of sori between the costae and pinna margins (3–6(–7) vs. 1(–2) rows). From S. triseriale , S. rex differs by the long-creeping, subterranean rhizome (vs. short-creeping and exposed), rhizome scales with clear lumen in the center of each cell (vs. colored lumen in cell-centers), pinna margins cartilaginous and crenate (vs. not cartilaginous and entire), and more rows of sori between the costae and pinna margins (3–7 vs. 1–4 rows).

Sanín et al. (2023) listed the following specimens for Bolivia: Pando: Manuripi, ca. 20 km S of Río Manuripi on the road to Chivé , 11°58’ S, 68°35’ W, 12 Aug 1982, Sperling & King 6595 ( BRIT *, F, MO, NY *, TEX, US *, WIS *) ; Santa Cruz: Nuflo de Chavez, 5 km al N de Perseverancia , 257 m, 14°38’ S, 62°37” W, 11 June 1990, Vargas 586 ( F *) .

( Serpocaulon silvulae (M.Kessler & A.R.Sm.) A.R.Sm. , Taxon 55(4): 929. 2006.)

According to Sanín et al. (2023), this species is not distinct from S. crystalloneuron .