Polystichum loratum (Dryopteridaceae), a New Fern Species from
Guizhou, China
Hai He and Yong-Qing Yang
College of Life Sciences, Chongqing Normal University, Shapingba, Chongqing 400047, China
Li-Bing Zhang*
Missouri Botanical Garden, P.O. Box 299, St. Louis, Missouri 63166-0299, U.S.A., and
Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu,
Sichuan 610041, People’s Republic of China.
*Corresponding author: libing.zhang@mobot.org
ABSTRACT. A new fern species, Polystichum loratum
H. He & Li Bing Zhang (Dryopteridaceae), is
described and illustrated from limestone cliffs in
northern Guizhou Province, China. Polystichum
loratum is most similar to P. yaanense Liang Zhang
& Li Bing Zhang in having narrowly ovate to
lanceolate abaxial rachis scales. The new species is
distinguished by its lorate leaf lamina, the oblong to
narrowly ovate microscales (broad-type) on abaxial
pinna surfaces, and the exindusiate sori, while P.
yaanense has lanceolate leaf lamina, subulate
microscales (narrow-type) on abaxial pinnae, and
indusiate sori. Polystichum loratum is considered to
be Critically Endangered (CR), based on IUCN Red
List criteria.
Key words: China, Guizhou, IUCN Red List,
limestone flora, Polystichum.
In the summer of 2011, Hai He and Yong-Qing
Yang conducted fieldwork in northern Guizhou,
China, to search for samples of Hypodematium
glandulosum Ching ex K. H. Shing (Dryopteridaceae
or Hypodematiaceae). On the way to the summit of
Jindingshan of Zunyi City, a city famous for the 1935
Zunyi Meeting in modern Chinese revolutionary
history, a species of Polystichum Roth (Dryopteridaceae) growing on limestone cliffs was collected and
photographed, and photos, specimens, and DNA
samples were sent to Li-Bing Zhang. After comparative morphological investigation, we conclude that
the species is unknown to science, and it is described
here.
Polystichum loratum H. He & Li Bing Zhang, sp.
nov. TYPE: China. Guizhou Province: Zunyi
Prefecture, Zunyi City, Jindingshan Town,
Xintugou Cun, Jiayanwo, 27846911.0299N,
106846914.2799E, 1150 m, on shaded & damp
limestone cliffs, 2–3 m distant from the ground,
NOVON 22: 166–169. PUBLISHED
ON
23 June 2011, H. He & Y. Yang 1361 (holotype,
CDBI; isotypes, CTC, MO). Figure 1.
Diagnosis. Polystichum loratum H. He & Li Bing
Zhang is most similar to P. yaanense Liang Zhang & Li
Bing Zhang in having narrowly ovate to lanceolate abaxial
rachis scales, but the new species is distinguished by its
lorate leaf lamina (vs. lanceolate in P. yaanense), the oblong
to narrowly ovate and broad-type microscales (vs. subulate
and narrow-type in P. yaanense) on abaxial pinna surfaces,
and the exindusiate sori.
Plants perennial, caespitose, evergreen; rhizome
ascending, 0.5–2.2 cm, 0.4–1.6 cm diam., with
remnant bases of old petioles, scaly at the base of
the petiole (but scales mostly worn out, incomplete,
and much darker in color); adventitious roots dull
brown when dry, 0.2–0.3 mm diam., nearly glabrous or
occasionally covered with lanate scales, the longer
roots once or twice branched with lateral rootlets to 1.8
cm. Leaves 8 to 18(to 25) per rhizome, (5.9–)
11.2–16.8 cm, leaf lamina appressed to substrate or
ascending; petioles green, (0.5–)1.5–4.8 cm, 0.3–1.2
mm diam. at middle, densely covered with spreading
scales; petiole scales generally 2.5–4.1 3 0.8–1.2 mm,
ovate to lanceolate, thin and papery, brown, apex
caudate, ending in a ca. 0.8 mm hairlike tip, base
rounded and slightly peltate in attachment, scale
margins with 0.5–0.8 mm wavy, hairlike outgrowths,
mixed with smaller scales (fewer and mostly on adaxial
petiole surface) deltoid to lanceolate, ca. 2 3 0.5 mm,
margins and apex also with hairlike outgrowths and
long hairlike tip; basal petiole scales worn and
incomplete, similar to those on rhizome, mostly without
marginal outgrowths and hairlike tips, thicker in
texture and dark brown in color. Leaf lamina lorate, 1pinnate, (4.5–)7.5–12.5 3 0.9–1.5 cm, apex acuminate, 6 narrowed toward base from the mid-portion
and tapering down; rachis 0.3–0.6 mm diam. at middle
of lamina, without proliferous bulbils, green and
concolorous as pinnae when fresh, yellowish green
30 NOVEMBER 2012.
doi: 10.3417/2012045
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2012
He et al.
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Polystichum loratum (Dryopteridaceae) from
Guizhou, China
Figure 1. Polystichum loratum H. He & Li Bing Zhang. —A. Habit. —B. Pinna. —C, D. Petiole scales. —E. Abaxial rachis
scale. —F, G. Microscales (broad-type microscales) of pinnae. A–G drawn from the holotype H. He & Y. Hang 1361 (CDBI).
when dry, densely covered with scales abaxially,
sparsely scaly (especially at base of petiolules)
adaxially; abaxial rachis scales ovate to lanceolate,
similar to those of petiole but smaller, lighter in color
and thinner in texture, adaxial rachis scales deltoid
and subulate, dark brown, to 2 3 0.4 mm, hairlike
outgrowths only at broadest base, margins nearly
entire, apex caudate; pinnae nearly leathery, in (16
to)25 to 55 pairs, alternate, 1–2 mm apart, contiguous
or imbricate (sometimes basal 1 to 6 pairs to 3 mm
apart even if other pinnae are imbricate), asymmetrically rectangular to oblong (or slightly falcate toward
apex), 3.5–6.5 3 1.8–3 mm, lowest pairs usually 1/2 to
2/3 as long as middle pinnae, asymmetrically deltoid
or widely so, shortly petiolulate (petiolules to ca. 1
mm, attached to rachis at an acroscopic angle of ca.
168
Novon
608), basiscopic margins at angles of 758–1508 with
rachis, the basiscopic base cuneate, acroscopic
side 6 truncate (with a blunt auricle, sometimes
auricle deeply incised to near midrib and forming a
basal free cuneate-based lobe of ca. 2 3 1.8 mm
with 2 or more small teeth at apex), forming angles
of 908–1208 at the point of attachment to the
petiolule, margins slightly cartilaginous, basiscopic
side of pinnae nearly entire, distally curved toward
apex, with 1 or 2 small teeth (distal margins
sometimes curved with 2 to 3 undulations),
acroscopic side of pinnae with 3 or 4 shallow
teeth between the basal auricle tooth and pinna
apex (sometimes also with 3 or more shallow or
rarely deep undulations), apex rounded or acute
(occasionally acuminate) and ending in a blunt
tooth, all teeth without aristate tips, adaxial pinna
surface glabrous (occasionally with 1 to 3 microscales), abaxial pinna surface sparsely covered with
microscales (especially along veins); microscales
oblong to narrowly ovate (Fig. 1F, G; broad-type
microscales), 0.8–1.2 3 0.15–0.25 mm, light
brown, membranous, apex extended by hairlike
appendage, microscale margins irregularly erose,
with the broadest part consisting of 6 to 8 lines of
cells; venation of pinnae pinnate, visible abaxially
and indistinct adaxially, lateral veins free, single or
once forked. Sori terminal on lateral veins, 2 to
4(5) on acroscopic side, 0 or 1 on distal basiscopic
side, 1.4–2.4 mm diam., mostly medial (between
pinna margins and midrib), proximal 1 or 2 sori
closer to pinna margins, occasionally all sori close
to pinna margins, centers ca. 1.5 mm apart from
one another, contiguous when mature; indusia
absent; sporangia round, ca. 0.2 mm diam., walls
ca. 0.1 mm thick, dark brown when mature; annuli
with ca. 15 thickened cells; sporangial stalks ca.
0.3 mm; number of spores per sporangium
unknown.
Polystichum loratum was observed to grow either
on shaded, damp limestone cliffs of a small gorge
(Jiayanwo, the type locale) or on unshaded, damp
cliffs under shrubs, as well as on the surfaces of
carbonate sediment at the bottom of the mouth of a
karst cave (Touniudong, Buffalo-Stolen Cave), at
1150–1300 m.
Plants associated with the type of Polystichum
loratum include the seed plants Boehmeria clidemioides Miq. var. diffusa (Wedd.) Hand.-Mazz.
(Urticaceae), Briggsia mihieri (Franch.) Craib (Gesneriaceae), Elatostema involucratum Franch. & Sav.
(Urticaceae), Hemiboea subcapitata C. B. Clarke
(Gesneriaceae), Saxifraga stolonifera Curtis (Saxifragaceae), Begonia L. (Begoniaceae), Petrocosmea Oliv.
(Gesneriaceae), and Polygonum L. (Polygonaceae).
Fern associates were Hypodematium crenatum
(Forssk.) Kuhn (Hypodematiaceae), Cyrtomium fortunei J. Sm., Polystichum craspedosorum (Maxim.)
Diels, and P. erosum Ching & K. H. Shing
(Dryopteridaceae).
Distribution and ecology. Polystichum loratum
is currently known only from Xintugou, an area
close to Jindingshan Town north of Zunyi City in
northern Guizhou. Jindingshan is a scenic mountain near Zunyi, and the area called Xintugou lies
within a valley at the western portion of the
mountain range; the northern side of Xintugou
includes elevated limestone cliffs, where P.
loratum is found. The areas surrounding Xintugou
correspond to a general karst landscape, but
without so many limestone outcrops. Given the
similarity of the adjacent karst topography to the
Xintugou area, we expect that similar habitats, and
thus the same plants, could possibly be found
during future fieldwork.
IUCN Red List category. Only four populations of
Polystichum loratum have been found at Xintugou,
with a total of an estimated 180 individuals (with the
smallest population having ca. 30 individuals). The
new species clearly should be classified as Critically
Endangered (CR), based on current information and
according to IUCN Red List criteria (IUCN, 2008).
However, a more extensive search is needed to
accurately assess the conservation status of the new
species.
Etymology. The species epithet is taken from the
Latin word ‘‘loratum,’’ meaning ‘‘lorate,’’ referring to
the general lorate outline of its lamina.
Taxonomic notes. Polystichum loratum has 1pinnate leaves and is clearly a member of Polystichum sect. Haplopolystichum Tagawa (1940) s.l.
(Zhang & He, 2009). The narrow strap-shaped, lorate
outline of the leaf lamina of P. loratum is reminiscent
of that of P. subacutidens Ching ex L. L. Xiang, which
is in the same section and is distributed from
southern China to northern Vietnam. However, P.
subacutidens has filiform rachis scales and linear or
filiform microscales on pinnae that clearly differ from
the new species. In Polystichum sect. Haplopolystichum s.l., P. loratum is one of only two species with
ovate to lanceolate rachis scales. The other species in
the section with ovate to lanceolate rachis scales is P.
yaanense (Zhang et al., 2012). In spite of the similar
shapes of the rachis scales, these two species can be
easily distinguished morphologically from each other.
Most important, P. loratum has oblong to lanceolate
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2012
He et al.
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Polystichum loratum (Dryopteridaceae) from
Guizhou, China
microscales on pinnae abaxially and exindusiate sori,
while P. yaanense has subulate microscales on
pinnae abaxially and indusiate sori. In addition, P.
loratum has linear leaf lamina and slightly cartilaginous pinna margins, while P. yaanense has lanceolate leaf lamina and noncartilaginous pinna margins.
Polystichum yaanense occurs in Ya’an Prefecture,
Sichuan. The morphological differences between P.
loratum and P. yaanense are elaborated in the
following key.
Acknowledgments. This project was supported by
the National Natural Science Foundation of China
(#31070187) and the Chongqing Municipality Science
and Technology Commission (#cstc2011jjA00006) to
H.H. and by a grant from the Open Laboratory of
Ecological Restoration and Biodiversity Conservation
of Chengdu Institute of Biology, Chinese Academy of
Sciences, to L.-B.Z. We are indebted to Yushan Li for
help with fieldwork, Faqiang Lü for the line drawing,
and two anonymous reviewers, as well as Sara Fuentes
and Victoria Hollowell, for helpful comments. Special
thanks go to the curators of CDBI, CTC, and MO for
giving us access to the materials in their care.
KEY
WITH
SPECIES OF POLYSTICHUM SECT. HAPLOPOLYSTICHUM S.L.
OVATE TO LANCEOLATE RACHIS SCALES IN CHINA
TO
1a. Leaf lamina lanceolate; pinnae stiff, nearly
transparent when dry with veins being visible
adaxially, not cartilaginous on margin; microscales of pinnae subulate; sori indusiate . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. yaanense
1b. Leaf lamina lorate; pinnae soft, not transparent
when dry with veins being indistinct adaxially,
slightly cartilaginous on margin; microscales of
pinnae oblong to narrowly ovate; sori exindusiate
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. loratum
Paratypes. CHINA. Guizhou: Zunyi City, Jindingshan
Town, Xintugou, Dongwan, Touniudong (Buffalo-Stolen
Cave), 1300 m, 23 June 2011, H. He & Y. Yang 1343,
1345, 1347, 1354 (CDBI, CTC); Jiayanwo, 1150–1200 m,
23 June 2011, H. He & Y. Yang 1356, 1360 (CDBI, CTC).
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yaanense (Dryopteridaceae), a remarkable new species
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