New Record of Ophioderma redactophylla (Ophioglossaceae) in the Philippines and New Insights to its Morphology

Abstract

Ophioderma redactophylla is a new fern species record for the Philippines discovered at Mt. Apo in North Cotabato Province, extending its original distribution from the Malay Peninsula (southern Thailand). New insights on its morphology are provided together with its conservation status and a revised dichotomous key to the Ophioderma in the Philippines.

Full text

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New Record of Ophioderma redactophylla
(Ophioglossaceae) in the Philippines
and New Insights to its Morphology
Fulgent P. Coritico1,2*, Yvonne Love L. Cariño2,
Maria Melanie M. Guiang1,2, and Victor B. Amoroso1,2
1Department of Biology, College of Arts and Sciences
2Center for Biodiversity Research and Extension in Mindanao (CEBREM)
Central Mindanao University, University Town, Musuan, Bukidnon 8710 Philippines
Ophioderma redactophylla is a new fern species record for the Philippines discovered at Mt.
Apo in North Cotabato Province, extending its original distribution from the Malay Peninsula
(southern Thailand). New insights on its morphology are provided together with its conservation
status and a revised dichotomous key to the Ophioderma in the Philippines.
Keywords: Mindanao, Mt. Apo, snake tongue fern
*Corresponding Author: cfulgent@cmu.edu.ph
INTRODUCTION
Ophioglossaceae is a family of fern with an estimated
112 species with temperate to boreal distribution (PPG
I 2016; Taylor et al. 2009). The family is represented
in the Philippines by 13 species and four genera.
Of these, there are two species of Botrychium, one
Helminthostachys, three Ophioderma, and seven
Ophioglossum (Pelser et al. 2011). Currently, there
are five species of Ophioderma in Southeast Asia
– one of which is a site endemic to the Philippines,
Ophioderma subsessile Amoroso et Coritico (Amoroso
et al. 2021). In previous years, there are new species
discovered and new records of ferns in the Philippines
like the discoveries of Actinostachys minuta (Amoroso
et al. 2020) and Ophioderma subsessile (Amoroso et
al. 2021), new records of Athyrium nakanoi Makino
(Coritico et al. 2019), Alsophila commutata Mett.
(Coritico et al. 2017), Phanerosorus major Diels
(Barcelona and Pelser 2014), Stenolepia tristis
(Blume) Alderw. (Chang et al. 2013) and Athyrium
erythropodum Hayata (Liu et al. 2008). With increased
sampling efforts, regional species numbers will likely
increase since many areas in the Malesian Region are
still unexplored and insufficiently sampled (Coritico
et al. 2019).
Mt. Apo Natural Park (MANP) is the highest peak
in the Philippines and one of the protected areas
in Mindanao. As one of the Philippine Long-term
Ecological Research sites and ASEAN heritage park,
it is home to different endemic species of plants and
animals (Kim et al. 2017; Coritico and Amoroso 2020).
During our recent botanical survey in Mt. Mahuson,
Apo Range, Magpet, North Cotabato, we encountered
a population of Ophioderma redactophylla growing
on leaf litter in the lower montane forest. A thorough
morphological examination of the specimens was done
and the identification was validated using the recent
taxonomic key of Chantanaorrapint et al. (2019). Here,
we provide new insights on the morphology, detailed
illustrations, photographs, and conservation status of O.
redactophylla – including the revised key to the species
of Ophioderma in the Philippines.
Philippine Journal of Science
151 (1): 227-233, February 2022
ISSN 0031 - 7683
Date Received: 21 July 2021

228
TAXONOMIC TREATMENT
Ophioderma redactophylla Chantanaorr. & Li Bing
Zhang (Figures 1 and 2)
Description. Plants terrestrial, 15.5–19.4 cm long,
perennial herbs. Root grows horizontally, branched,
fleshy, without root hairs, young buds covered in sheath-
like stipules. Rhizome short, non-tuberous with roots
emerging laterally and aerial parts upwardly. Aerial parts
solitary, erect, not circinate up to 19.4 cm, consisting of
two parts: trophophore and sporophore. Trophophore
erect, linear, gradually attenuate into the common stalk
with sporophore, hardly discernible stipe, 9–13 cm long,
glabrous, basal lamina 1.5–2 mm wide; middle lamina
2.5–4 mm wide; upper lamina 2–2.5 mm wide; apex
acute to obtuse; venation reticulate consisting of primary
veins only. Sporophore 3.2–4.6 cm long arising almost at
the apex of the trophophore, consisting of peduncle and
a fertile spike; peduncle 1.0–1.7 cm, fertile spike 2.2–2.6
cm long, 3–4 mm wide, sterile appendage up to 2 mm;
sporangia arranged in two rows, 18–28 pairs, arranged
alternately, opening transversely. Spores yellowish, trilete,
globose, 36–42 μm in equatorial diameter.
Habitat and distribution. Tropical lower montane rain
forest amongst leaf litter, at about 900 m asl (above sea
level) in Thailand and about 1100 m asl in the Philippines
(Mindanao). It is also noteworthy to mention that
Ophioderma subsessile – a recently discovered species in
Central Mindanao, Philippines – was also observed within
the mountain range, thus extending its distribution in the
Southern Mindanao, Philippines.
Notes and new morpho-anatomical insights. Ophioderma
redactophylla is known only from Betong District, Yala
Province, near the Thai-Malaysian border. It might also
occur in Southern Thailand and Peninsular Malaysia
according to Chantanaorrapint et al. (2019). Here we
affirm that this species extends its distribution from the
Malaysian border to the southern Philippines based on
the morpho-anatomical comparison of our Philippine
specimens with the closest species of Ophioderma,
Ophioderma redactophylla, and O. subsessile (Table 1).
Our Philippine material is similar to O. redactophylla
on the following morpho-anatomical features: a) non-
tuberous rhizome, b) frond length, c) hardly discernible
stipe, d) trophophore lamina shorter than the sporophore,
and e) sporophore arising almost at the apex of the
trophophore. The quantitative differences in the length of
sporophore characters of our Philippine material, and O.
redactophylla may be attributed to phenoplasticity brought
about by differing environmental conditions.
Ophioderma redactophylla Chantanaorr. et Li Bing Zhang
as published by Chantanaorrapint et al. (2019) has not
been investigated anatomically. Here, our Philippine
materials were sectioned to provide new insights on
anatomy. Transection of the Philippine material revealed
noteworthy features, as shown in Figure 2: a) presence
of abundant arbuscular mycorrhizal fungi in root cortical
tissues and including the rhizome cortex, which was also
observed in O. subsessile; b) haplostelic vascular strand
of the root, transformed into a c-shaped vascular strand in
the rhizome; c) the vascular bundles increase in number
from the root to the lamina and the cells are mostly
parenchymatous except on the stele portion.
Specimens Examined
Philippines. Mindanao Island. Cotabato: Magpet
Municipality, Mt. Mahuson, Apo Range 7°11’24.67”
N 125°9’49.52” E, 1100 m asl 15 October 2020, V.B.
Amoroso & J.C. Nobleza 19362 (CMUH).
Specimens Examined for Comparison
Ophioderma subsessile Amoroso & Coritico.
PHILIPPINES. Mindanao Island. Bukidnon: San Fernando
Municipality, Mt. Pantaron Range 7°52’12.39’’N
125°24’11.43’’, 820 m asl, 20 August 2020, V.B. Amoroso
& J. Nobleza 18966 (holotype: PNH! Isotypes: CMUH!
BRIT!)
Revised Taxonomic Key of Philippine Ophioderma
1. Plants epiphytic; frond pendu-
lous and ribbon-like ................ O. pendula
1. Plants terrestrial; frond erect
and simple ............................... 2
2. Rhizome tuberous; tropho-
phores not reduced; stipe
discernible .............................. 3
2. Rhizome non-tuberous; tro-
phophores reduced; stipe hard-
ly discernible .......................... O. redactophylla
3. Stipe up to 12 cm long; tropo-
phore shorter than sporophore
................................................. O. intermedia
3. Stipe shorter up to 5 cm long;
tropophore longer than sporo-
phore ....................................... O. subsessile
Conservation Status
Mt. Mahuson, Sitio V in Magpet, North Cotabato is part
of the buffer zone of Mt. Apo in the North Cotabato side.
The population of O. redactophylla is very limited in the
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Figure 1. Philippine material of Ophioderma redactophylla: [A] habit, [B] emergence of sporophore from trophophore, [C] reduced
trophophore, [D] rhizome covered in sheath-like stipules (st), [E] emerging young root (r), [F] reduced trophophore (red arrow),
[G] adaxial surface of sporophore, [H] abaxial surface of sporophore, [I] stomata, [J] proximal view of spore, and [K] distal
view of spore.
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Figure 2. Philippine material of Ophioderma redactophylla: [A] whole plant; [B–I] cross-sections of [B] rhizome,
[C] root with endophytic fungus, [D] stipe, [E] lower lamina, [F] middle lamina, [G] upper lamina, [H]
peduncle, and [I] fertile spike with ruptured sporangia.
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Characters O. subsessile Amoroso & Corit-
ico (Amoroso et al. 2020)
O. redactophylla Thailand
material (Chantanaorrapint et
al. 2019)
O. redactophylla Philippine
material
Habitat Terrestrial, growing on fallen de-
caying trunk in lowland tropical
rain forest, 820 masl
Terrestrial, growing amongst leaf
litter in lower montane forests,
900 masl
Terrestrial, growing amongst leaf
litter in tropical lower montane
rain forest, 1100 masl
Root Unbranched, eshy without root
hairs, producing young buds cov-
ered with sheath-like stipules
Branched, eshy, often producing
young buds. They referred this one
as underground part
Branched, eshy without hairs
producing young buds covered in
sheath-like stipules
Rhizome Globose, 3–5 mm thick, bearing
1–4 fronds
Non-tuberous, 2 mm in diameter Non-tuberous, 2–3 mm in diam-
eter; covered with sheath-like
stipules; bearing 1–3 fronds
Frond length (cm) 15–25 15–20 15.5–19.4
Stipe Discernible, 3–5 m long, gradual-
ly merging into the lamina
Hardly discernible Hardly discernible
Trophophores
Lamina Undulate, lanceolate, erect, rarely
bifurcate
Flat, linear, erect Linear, erect
Lamina length (cm) 15–25 8–15 9–13
Basal lamina width (mm) 3.0–4.0 2.0–2.5 1.5–2.0
Middle lamina width
(mm)
6.0–9.0 No data 2.5–4.0
Figure 3. Distribution of Ophioderma redactophylla in the Philippines.
Table 1. Major characteristics delineating Ophioderma redactophylla Philippine specimen, O. redactophylla Thailand specimen, and O. subsessile.
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Characters O. subsessile Amoroso & Corit-
ico (Amoroso et al. 2020)
O. redactophylla Thailand
material (Chantanaorrapint et
al. 2019)
O. redactophylla Philippine
material
Upper lamina width (mm) 3.0–6.0 3.0–5.0 2.0–2.5
Lamina base Narrowly attenuate Gradually attenuate Gradually attenuate
Lamina apex Sub-acute to obtuse Acute to obtuse Acute
Venation reticulate Not observed reticulate
Length of trophophore vs.
sporophore
Trophophore mostly always
longer than sporophore
Trophophore always shorter than
sporophore
Trophophore shorter than the
sporophore
Sporophores
Origin Arising at the middle part of
trophophore
Arising almost at the apex of
trophophore
Arising almost at the apex of the
trophophore
Length (cm) 2.5–3.3 4.5–6.5 3.2–4.6
Peduncle length (cm) 0.3–1.4 3.0–4.5 1.0–1.7
Fertile spike length (cm) 1.8–2.7 1.2–2.0 2.2–2.6
Fertile spike width (mm) 3–4 No data 3–4
Number of sporangia 20–28 pairs 15–24 pairs 18–28 pairs
Sterile appendage Broad, 1–2 mm wide Almost lacking Up to 1 mm
Spore Trilete, yellowish Trilete, yellowish Trilete, yellowish
Distribution Pantaron Range, San Fernando,
Bukidnon, Philippines
Betong District, Yala Province
Thai-Malaysia border
Mt. Mahuson, Apo Range, Mag-
pet, North Cotabato, Philippines
ritual site of Obu Manuvu tribe with an area of not more
than 1/4 hectare. Few populations were also observed
in the opposite site of the ritual site near the open road.
Furthermore, the extent of occupancy is also very narrow
with an estimated area of half a hectare. The population of
mature plants does not exceed 20 individuals. Threats to
the population of O. redactophylla include infrastructure
development, i.e. road, ecotourism activities, agricultural
expansion, poaching, habitat degradation, and competition
of non-native species. During the fieldwork in 2020,
invasive plant species such as Piper aduncum L.,
Chromolaena odorata (L.) R.M.King & H.Rob., Mikania
cordata Lehm., and Pteridium aquilinum (L.) Kuhn were
observed, which will lead to the decline in population O.
redactophylla.
Using the International Union for Conservation of Nature
(IUCN) criteria in evaluating the conservation status, it
falls in Critically Endangered based on its very small
and restricted population, likely continuing decline due
to disturbance present from the foot trail and an area of
occupancy estimated to be < 10 km2 (IUCN Standard and
Petition Committee 2019).
ACKNOWLEDGMENTS
The authors express their gratitude to the Department of
Science and Technology Grants-In-Aid for funding this
research. We thank the Department of Environment and
Natural Resources–Region XII Office for the issuance
of the Gratuitous Permit No. 2020-14; the Philippine
Council for Agriculture, Aquatic, and Natural Resources
Research and Development for monitoring the research;
the indigenous tribe association (Nova-a’an Pottung
to Tanong Buwis to Tinonanon Ka-ay’t Tinanan); Ms.
Joevina C. Nobleza for the help in specimen collection;
Erl Pfian T. Maglangit for providing the map and the
administration of Central Mindanao University led by Dr.
Jesus Antonio G. Derije for logistical support during the
conduct of this botanical survey.
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