Schizaea erecta Amoroso &amp; Coritico 2023, sp. nov
Creators: name: Amoroso, Victor B.
name: Acola, Mescel S.
name: Guiang, Maria Melanie M.
name: Acma, Florfe M.
name: Fritsch, Peter W.
name: Coritico, Fulgent P.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Polypodiopsida
Schizaeales
Schizaeaceae
Schizaea
Schizaea erecta

description: <i>Schizaea erecta</i> Amoroso &amp; Coritico, <i>sp. nov</i> (Figs. 2–4) Type:— PHILIPPINES. Dinagat Island: Municipality of Tubajon, Paragua Forest, 10.29355°N, 125.58594°E, 65 m, 30 January 2023, <i>V. B</i> <i>. Amoroso with F. P. Coritico &amp; M. M.</i> <i>Guiang. 3003</i> (holotype PNH!, isotypes CMUH!, BRIT!). <b>Diagnosis:</b> — <i>Schizaea erecta</i> resembles <i>S. dichotoma</i> in having hairy rhizomes, dimorphic fronds, stipes with a t-shaped xylem strand, laminae fan-shaped and branching dichotomously, stomata hypocytic, sorophores pinnately arranged in 2 rows, and sporangia with long non-glandular hairs, but differs by having a rhizome with short-appressed brown hairs (vs. long, coarse brown hairs), the stipe longer and up to 26.6 cm long with a narrow groove (vs. up to 20 cm long and deeply grooved), fronds 3–5 times branching dichotomously (vs. 6–8 times branching), narrower (8–14 cm long by 2.0– 4.5 cm wide), and consistently erect fronds (vs. 15 cm long by 17 cm wide, not erect), sorophores up to 39 per stipe with 12–16 lobes alternately arranged (vs. up to 34 with 5–10 lobes oppositely arranged), and sporangia oblong with long white hairs (vs. reniform with brown hairs). <b>Description</b>:—Terrestrial, 30–50 cm long. <i>Rhizomes</i> short creeping, 1.5–5.0 cm below ground, 0.3 mm thick, covered with persistent shiny brown appressed hairs 1–2 mm long. <i>Fronds</i> dimorphic, crowded, irregularly branched; <i>sterile fronds:</i> erect, stipes distinct, 18.5–26.6 cm long, base partly buried in ground, blackish and becoming light green in upper portion, slightly winged at middle to distinctly winged at apex, with shallow groove and scattered short hairs; laminae fan-shaped, 9–15 cm long and each axis 1 mm wide, whole laminae 2–4 cm wide, costae distinct, branching dichotomously 3–5 times; <i>fertile fronds</i> erect, stipes 11–27 cm long, tetragonal in transection and distinctly winged in upper portion; lamina fan-shaped, 8–14 × 2.0– 4.5 cm, branching dichotomously 3–5 times, basal branch slightly flattened, 1–2 mm wide, distal branch up to 0.5 mm wide with scattered small projections (bases of glandular hairs). <i>Sorophores</i> born distally of each branch of frond, 5–12 mm long, 24–39 per stipe, bearing 12–16 pairs of lobes, pinnately arranged in 2 rows and opposite in arrangement. <i>Sporangia</i> in two rows associated with long white non-glandular hairs, with opposite to alternate arrangement, loosely arranged at base and tightly packed in upper part, oblong with short stout stalk, brown, annulus apical, opening by a vertical slit. <i>Spores</i> monolete and reniform, 37 µm in diameter. <b>Etymology</b>:—The specific epithet refers to the erect fronds of the species. <b>Suggested common name:—</b> Dinagat grass fern. <b>Distribution and habitat:</b> — <i>Schizaea erecta</i> is known only from open habitat at 65 m elevation. It grows as a terrestrial plant in colonies with rhizomes growing below the ground in ultramafic soil associated with plants such as <i>Dicranopteris linearis</i> (Burman 1768: 235) Underwood (1907: 250), <i>Imperata cylindrica</i> (Linnaeus 1759: 878) Palisot de Beauvois (1812: 165), <i>Piper</i> sp., <i>Pteridium aquilinum</i> (Linnaeus 1753: 1075) Kuhn in Decken (1879: 11), <i>Pteris cretica</i> Linnaeus (1767: 130), and <i>Smilax</i> sp. (Figure 5). <b>Conservation Status:—</b> Dinagat Island was identified as a critical terrestrial conservation priority in the Philippines (Ong <i>et al</i>., 2002). Logging, mining, and land conversion threaten the entire island (Haribon, 2004). <i>Schizaea erecta</i> is known only within the Paragua forest, Municipality of Tubajon, with an estimated number of 30 individuals growing in just one open area near agricultural land. The habitat is prone to land conversion because of nearby residential areas. Thus, we recommend listing the species as critically endangered based on its restricted population with ≤ 50 mature individuals and the extent of occurrence estimated to be ≤ 10 km 2 (IUCN Standards and Petition Committee 2019). <b>Discussion</b>: <i>— Schizaea erecta</i> is most similar to <i>S. dichotoma</i>, based upon descriptions of Holttum (1959) and Sofiyanti <i>et al.</i> (2019), and examination of JSTOR type images and Co’s Digital Flora of the Philippines (Table 1). The species share nearly the same height and the presence of hairs on their rhizomes. Their fronds are dimorphic with fan-shaped lamina which branch dichotomously, they both have hypocytic stomata, and they both possess two rows of sorophores. However, the new species differs from <i>S. dichotoma</i> in having rhizome hairs 1.0– 2.3 mm long (vs. 2–3 mm) (Figure 2B); sterile fronds branching dichotomously 4–5 times (vs. 6–8 times) (Figure 2C). Further, the frond is consistently erect whereas that of <i>S. dichotoma</i> is not erect (Figure 2A). The sorophore of <i>S. erecta</i> has 12–16 pairs of lobes whereas <i>S. dichotoma</i> has 5–10 pairs. The sporangia of <i>S. erecta</i> are oblong whereas <i>S. dichotoma</i> has reniform sporangia (Figure 2G, H). Ke <i>et al</i>. (2022) and Brownsey &amp; Perrie (2014) stated that the <i>S. dichotoma</i> complex exhibits wide morphological and cytological variation. However, most members of this complex are poorly characterized and have been collectively lumped into “ <i>S. dichotoma</i> ”, which was found to be polyphyletic in the phylogeny of Ke <i>et al.</i> (2022). Although our new species was not included in this phylogeny, we reckon that it is morphologically so distinct that it merits treatment as a separate species, especially in anticipation of further splitting in this group. With the recognition of this new species, there are now 21 species of <i>Schizaea</i> worldwide (PPG I, 2016) and three in the Philippines. The salient anatomical features of <i>Schizaea erecta</i> include the following: the rhizome is almost circular with appressed hairs as outgrowths of the epidermal cells. The cortex is mainly composed of parenchyma cells. The stele is a haplostele with the phloem surrounding the xylem tissue (Figure 3B). The stipe shape changes from tetragonous at the base with indistinct costa and concave with narrow groove at the middle and somewhat flattened in the upper stipe with two distinct grooves and wings. The cortex becomes complex, being composed of the outer cortical sclerenchyma and the inner cortical parenchyma cells with the stele becoming actinostele and with a T-shaped xylem strand (Figure 3C–E). The lamina is flattened at the lower axis with distinct costa and incurved at the apical axis. The outer wall of the smaller epidermal cells is thickened and inwardly with large hypodermal cells. The vascular bundle is surrounded by a layer of large endodermis and a single layer of pericycle as also reported by Sofiyanti <i>et al.</i> (2019). Moreover, both surfaces of the costa have large sclerenchyma cells to protect the inner undifferentiated mesophyll from drying as the plants are found in open area. The guard cells protrude on the abaxial surface of the epidermis and connect to the large intercellular spaces. The anatomy of <i>Schizaea erecta</i> differs from that of <i>S. dichotoma</i> in the rhizomes for having larger outer cortical cells and smaller inner cortical cells (vs. smaller outer cortical cells and larger inner cortical cells), vascular bundles surrounded by ring-like sclerenchymatous cell layers (vs. star-shaped sclerenchymatous cell layers), numerous metaxylem (vs. 4 metaxylem); stipe tetragonous at the base and flattened in the upper stipe with narrow groove (vs. M-shaped and deeply grooved); lamina narrowly grooved (vs. deeply grooved), and guard cells protruding from the abaxial surface (vs. guard cells sunken).
description: Published as part of <i>Amoroso, Victor B., Acola, Mescel S., Guiang, Maria Melanie M., Acma, Florfe M., Fritsch, Peter W. &amp; Coritico, Fulgent P., 2023, A new species of grass fern, Schizaea erecta (Schizaeaceae), from Dinagat Island, Mindanao, Philippines, pp. 265-273 in Phytotaxa 618 (3)</i> on pages 267-272, DOI: 10.11646/phytotaxa.618.3.4, http://zenodo.org/record/8406837
description: {"references": ["Burman, N. L. (1768) Flora Indica. C. Haak, Leiden, 241 pp.", "Underwood, L. M. (1907) American ferns - VIII. A preliminary review of the North American Gleicheniaceae. Bulletin of the Torrey Botanical Club 34: 243 - 262. https: // doi. org / 10.2307 / 2560334", "Linnaeus, C. (1759) Systema Naturae Ed. 10. L. Salvius, Stockholm (Holmia), 1384 pp.", "Palisot de Beauvois, A. M. F. J. (1812) Essai d'une nouvelle agrostographie. Fain, Paris, 182 pp.", "Linnaeus, C. (1753) Species Plantarum. L. Salvius, Stockholm (Holmia), 1200 pp.", "Decken, C. C. von der. (1879) Reisen in Ost-Afrika in 1859 - 1861, Bd. 3, Abt. 3 Botanik. Leipzig, 91 pp.", "Linnaeus, C. (1767) Mantissa Plantarum. L. Salvius, Stockholm (Holmia), 142 pp.", "Ong, P. S., Afuang, L. E. &amp; Rosell-Ambal, R. G. (2002) Philippine biodiversity conservation priorities: a second iteration of the national biodiversity strategy and action plan. Department of Environment and Natural Resources - Protected Areas and Wildlife Bureau, Conservation International Philippines, Biodiversity Conservation Program - University of the Philippines Center for Integrative Development Studies, and Foundation for the Philippine Environment, Quezon City, Philippines, 23 pp.", "Haribon (2004) Technical report: Mts. Kambinliw &amp; Redondo, Loreto, Dinagat Island, Surigao del Norte. Haribon Foundation for the Conservation of Natural Resources, Inc., 140 Kalayaan Avenue, Quezon City, Philippines 1101, 69 pp.", "Holttum, R. E. (1959) Schizaeaceae. Flora Malesiana Series 2, Pteridophyta 1 (1): 37 - 61.", "Sofiyanti, N., Iriani, D. &amp; Fitmawati (2019) The first record of grass-like fern, Schizaea dichotoma (L.) J. Sm. (Schizaeaceae) from Lingga Island, Indonesia: Its morphological, anatomical and palynological study. Biodiversitas 20 (9): 2651 - 2660. https: // doi. org / 10.13057 / biodiv / d 200930", "Ke, B. F., Wang, G. - J., Labiak, P. H., Rouhan, G. on behalf of GoFlag Consortium, Chen, C. - W., Shepherd, L. D., Ohlsen, D. J., Renner, M. A. M., Karol, K. G., Li, F. W. &amp; Kuo, L. - Y. (2022) Systematics and plastome evolution in Schizaeaceae. Frontiers in Plant Science 13: 1 - 14. https: // doi. org / 10.3389 / fpls. 2022.885501", "Brownsey, P. J. &amp; Perrie, L. R. (2014) Schizaeaceae. In: Breitwieser, I., Heenan, P. B. &amp; Wilton, A. D. (Eds.) Flora of New Zealand - Ferns and Lycophytes. Fascicle 5. Manaaki Whenua Press, Lincoln, pp. 1 - 9. http: // dx. doi. org / 10.7931 / J 2 G 44 N 6 J"]}