Botanical Studies (2009) 50: 261-267.
*
Corresponding author: E-mail: ymshui@mail.kib.ac.cn;
Tel: +86-871-521-5804.
INTRODUCTION
In May 2004, during a survey of the limestone flora
in SE Yunnan, China, we found three populations, each
containing 20-50 individuals, of an unusual plant of the
Acanthaceae, which we determined to be Pararuellia
Bremek. (Acanthaceae). Pararuellia is distinguished
from Ruellia by its terminal, dense spike, and Asiatic
distribution (Bremekamp and Nannenga-Bremekamp,
1948). Pararuellia contains about eight species in SE Asia,
Indochina, and Malaysia, and four in China (Tsui, 2002)
(P. alata H. P. Tsui, P. cavaleriei [H. Lev.] E. Hossain,
P. hainanensis C. Y. Wu & H. S. Lo, and P. delavayana
[Baill.] E. Hossain).
The region where this plant was found has high
temperature, little rain, and thin soil. The yearly averages
of rainfall are about 800 mm, and the yearly averages of
temperature are about 23.70X. The vegetation is dominated
by shrubs and grasses. Of the plants we found, two were
moved to the botanical garden of the Kunming Institute
of Botany, Chinese Academy of Sciences. The plants
flowered and fruited the following year, and there are now
more than 30 individuals in cultivation.
The unusual species appears to be rare and endemic to
the hot and dry valleys in SE Yunnan. Further examination
of some herbaria (KUN, PE) revealed a collection from
near Nansha, Yuanyang Xian, Yunnan, in 1973. The
locality is only one kilometer from the localities found in
2004. So far, the total area of distribution covers no more
than fifteen square kilometers along the Hong He (Red
River) Valley of SE Yunnan. If the species is as rare as
collections indicate, it is urgently in need of protection.
Pararuellia glomerata (Acanthaceae), a new species from
Yunnan, China
Wen-Hong CHEN
1
, Yu-Min SHUI
1,
*, Yong-Kang SIMA
2
, Rong-Mei ZHANG
1,3
, and Zhi-Dan WEI
1,3
1
Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650204, P. R. China
2
Key Laboratory of Rare and Endangered Plants, Yunnan Forestry Academy, Kunming 650204, P. R. China
3
Graduate School of the Chinese Academy of Sciences, Beijing 100049, P. R. China
(Received November 15, 2007; Accepted October 16, 2008)
ABSTRACT.
Pararuellia glomerata Y. M. Shui & W. H. Chen is described and illustrated as new species
from Yunnan, China. It is similar to P. cavaleriei (H. Lev.) E. Hossain and Pararuellia delavayana (Baillon) E.
Hossain, but differs by its cylindric spike and dense imbricate homomorphic bracts. Pollen grains, seeds and
cross sections of the leaf epidermis are reported for this species of arid environments.
Keywords: Acanthaceae; China; Leaf cross section; Leaf epidermis; New species; Pararuellia glomerata;
Pollen; Seeds.
The plant is characterized by constricted internodes,
subrosulate leaves, a terminal dense spike with imbricate
flowers, ovules 5 or 6 per carpel, and 3-pored globose
pollen grains with alveolate exine. These characters clearly
place it in the genus Pararuellia. After consulting the
literature (Benoist, 1935; Tsui, 2002; Hu and Tsui, 2006)
and examining specimens, we determined these plants
to be a previously undescribed species, which we here
describe and illustrate.
Pararuellia glomerata Y. M. Shui & W. H. Chen, sp.
nov.XTYPE: China, Yunnan Province, Gejiu, 200 m,
30 Apr 2004, Y. M. Shui, W. H. Chen, M. D. Zhang
40746 (holotype: KUN; isotypes: IBSC, PE).
yJa֮
Figures 1, 3
Species nova spicis cylindratis et bracteis omnino
homomorphis imbricatis a congeneribus valde differt.
Perennial herbs. Stems 1-2 cm long; internodes 2-4,
constricted, 0.5-1.1 cm long, nodes adventitiously rooted
when touching ground, forming a new stem. Leaves
opposite, subrosulate; petiole 1.3-3.4 cm long, densely
hispid; blade oblanceolate, obovate-oblong or spatulate,
4-6.2 1.8-3.2 cm, base gradually narrowed and decurrent
into petiole, margin erose or crenate, apex round to acute,
abaxially densely hispid, adaxially slightly hispid, lateral
nerves 6-9 pairs, prominent on both surfaces. Spike
terminal, cylindrical, (0.6-)3.2-5.4 cm long, 0.8-1.1 cm in
diam., of numerous verticillate cymes; cyme contracted,
1- or 2-flowered.
Peduncle 0.7-5 cm long, densely hispid,
elongate to ca. 13 cm in fruit. Rachis (0.6-) 3.0-5.5 cm
long, densely hispid, nodes (3 or) 4-10, elongate to 7 cm
in fruit. Bracts numerous, homomorphic, distributed along
rachis, imbricate, ovate, or spatulate, 8-10 6-9 mm,
pinninerved, densely hispid, apex acute. Bracteoles linear-
SYSTemATICS
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Botanical Studies, Vol. 50, 2009
Figu re 1. Illustration of Pararuellia glomerata Y. M. Shui & W. H. Chen (drawn by Rong-Mei Z hang from the holotype). A,
Plant; B, Flower; C, Dorsal view of anther; D, Anterior view of anther; E, Lateral view of anther; F, Opened anther; G, Fruit; H,
Seed.
lanceolate, 3-4 ca. 1 mm, apex acuminate, basal part
of adaxial surface sparsely hispid, apical part of adaxial
surface densely hispid. Calyx 5-lobed nearly to base,
tube ca. 1 mm long, lobes linear, subequal, ca. 4 0.7
mm, hispid, elongate, to ca. 6 mm long in fruit. Corolla
light purple, bluish or pink, outside slightly hispid, inside
glabrous; corolla tube 0.8-1.3 cm long, 1.5-2 mm in diam.,
outside sparsely hispid, inside glabrous, throat oblique and
inflated, 2.5-4 mm long, 3-4 mm in diam., limb 5-lobed,
lobes equal, nearly round or trapeziform, 7-8 5-7 mm,
apex round or truncate. Stamens 4, didynamous, anthers
elliptic, ca. 1.1 mm long, filaments glabrous, the longer
filaments 1.5-3 mm long, inserted 0.8-1.5 mm from base
of throat, shorter ones ca. 0.5 mm long, inserted at base
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CHEN et al. X New species of
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263
Figure 2. Pararuellia glomerata. A, Pollen grain; B, Exine ornamentation of pollen grain; C, Seed; D, Basal view of seed; E,
Hairs on surface of seed; F, Cells and stomata on lower leaf surface; G, Articulatory attachments like cuticula rized hairs; H,
Stomata on lower leaf surface; I and J, Cross sections of leaf blade, showing epidermal cells, palisade tissue and spongy tissue
of leaf blade, corneous layer, calcium oxalate crystals in cells of leaf blade, stomata, and air chambers. Reference: CL: corneous
layer; COC: calcium oxalate crystals; EC: epidermal cells; PT: palisade tissue; SA: stomata; ST: spongy tissue.
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of throat. Ovary cylindrical, 2-2.5 mm long, ca. 1 mm in
diam., glabrous, ovules 5 or 6 per locule; style 0.8-1.4
cm long, pubescent, stigma 2-lobed, linear, longer lobe
2.3-2.6 mm long, shorter lobe ca. 1.3 mm long, pubescent.
Capsules cylindrical, 1-1.5 cm long, 2-3 mm in diam.,
pubescent, 2-valved, seeds 5 or 6.
Additional specimens examined. China, Yunnan
Province, Gejiu, 29 Apr 2004, alt. 360 m, Y. M. Shui, W.
H. Chen, M. D. Zhang 40729 (KUN); Yuanyang, near
Nansha, 12 Nov 1973, roadsides, 330 m, D. D. Tao 1433
(KUN, PE).
Etymology. The epithet glomerata refers to the densely
arranged bracts of the inflorescence.
Phenology. Flowering Apr to Jul; fruiting Jun to Aug.
Distribution and Habitat. Restricted to limestone
thickets at 200-500 m in hot dry valley of the Hong He
(Red River) in SE Yunnan, China. The accompanying
species are depauperate. For example, Sapium insigne
(Royle) Benth. ex Hook. f. is only 4-6 m tall (vs. to 40 m
tall in tropical rain forests in SE Asia). Other associated
small trees and shrubs include Bauhinia viridescens
Desv., Bauhinia yunnanensis Franch., Burretiodendron
kydiifolium Y. C. Hsu & R. Zhuge, Cycas hongheensis S.
Y. Yang & S. L. Yang ex D. Y. Wang, Euphorbia royleana
Boiss., Garuga forrestii W. W. Smith, Grewia celtidifolia
Juss., Lannea coromandelica (Houtt.) Merr., Millettia
cubittii Dunn and Wrightia arborea (Dennst.) Mabberley.
Jasminum yuanjiangense P. Y. Bai , Secamone sinica
Hand.-Mazz. are associated vines, and Calophanoides
yunnanensis (W. W. Sm.) C. Y. Wu is a common herb.
Notes. Pararuellia glomerata is similar to P. cavaleriei
(H. Lev.) E. Hossain and Pararuellia delavayana (Baill.)
E. Hossain, but differs in its robust cylindrical spikes and
homomorphic imbricate bracts. Pararuellia cavaleriei and
Pararuellia delavayana have heteromorphic bracts (viz.
Figure 3. The field images of Pararuellia glomerata. A, Plant; B, Inflorescences; C, Face and side views of flowers; D, Flower,
expanded. All images from holot ype specimen. Photographed by Y. M. Shui.
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CHEN et al. X New species of
Pararuellia
265
foliose at base of rachis, and gradually reduced distally),
spikes slender with free bracts. Pararuellia glomerata also
differs from P. cavaleriei by its larger bracts (8-10 mm vs.
1-2 mm long), and from P. delavayana by its spikes with
(3-) 4-10 nodes (vs. 1 or 2 [or 3] nodes). The following
key can be used to distinguish the Chinese species of
Pararuellia (Acanthaceae).
1a.
Bracts of rachis longer than internodes, imbricate,
homomorphic; spikes robust, cylindrical ......................
................................................... Pararuellia glomerata
1b.
Bracts of rachis shorter than internodes, free, usually
heteromorphic; spikes usually slender, flagelliform.....2
2a.
Nodes of spike usually 1 or 2 (rarely 3) ..................
...........................................................P. delavayana
2b.
Nodes of spike usually 4.........................................3
3a.
Rachis straight, wingless KKKKKK...K...4
3b.
Rachis usually zig-zag, winged below nodes
KKKK.K...................................KKP. alata
4a.
Bracts oblong, elliptic or ovate ....................
..................................................P. cavaleriei
4b.
Bracts cordate or suborbicular KKKK ....
.............................................. P. hainanensis
We also examined the pollen and leaf morphology, the
results of which are described below.
mATeRIALS AND meTHODS
Plant materials
The pollen for SEM work was taken from the type
specimen. Seeds and leaves were taken from living plants
of the type location. Voucher specimens are deposited in
the Herbarium of the Kunming Institute of Botany (KUN).
micromorphology of pollens grains and seeds
under Sem
Mature and dry pollen grains and seeds were cleaned
in water using ultrasound. For SEM they were air-dried,
affixed to aluminum specimen holders and sputter-coated
with gold. Morphological observations and micrographs
were made using a Hitachi-S-3000N ESEM. Terminology
for pollen morphology of Acanthaceae follows Erdtman
(1971) and Punt et al. (2007).
morphology and anatomy of leaf blade under
Lm
Epidermal characters of leaves were observed. Fresh
leaves were fixed in FAA (formaldehyde: 100% acetic
acid: 70% alcohol = 5:5:90) and dissociated using Jeffreys
reagent (10% nitric acid: 10% potassium dichromate =
1:1). The leaf epidermis was stained in a 0.5% safranin
solution, dehydrated via an alcohol series, and mounted
on a microscope slide. The slides were sealed in neutral
balsam and observed under an Olympus microscope.
Anatomical characters of leaves were observed in
paraffin sections. Leaves were fixed in FAA, dehydrated
via an alcohol series, embedded in paraffin and sectioned
at 12 gm thickness with a sliding microtome, stained in a
safranin and fast green solution, sealed in neutral balsam,
and observed under an Olympus microscope.
ReSULTS
Pollen and seed morphology
Pollen grains are globose, 45-45.3 gm in diam. The
exine ornamentation is alveolate, with thickish, spiny
muri, irregularly shaped lumina, and three distinct pores
(Figure 2A-B). These characters are consistent with those
of Pararuellia (Bremekamp and Nannenga-Bremekamp,
1948), especially with the characters of the pollen of
Pararuellia alata and P. delavayi (Hu et al., 2005),
confirming Pararuellia glomerata to be a member of the
genus Pararuellia.
The seeds are lenticular, broadly ovate or suborbicular
in face view, 1-1.5 1-1.5 mm. The base of the seed is
glabrous, but the remaining surface is covered with dense,
long, white, appressed hairs (Figure 2C-E).
Characteristics of leaf epidermis and leaf cross
section
Leaf epidermal terminology follows Dilcher (1974)
and Wilkinson (1979). Pararuellia glomerata has
hypostomatic leaves. The epidermal cells of the lower leaf
surface are irregular and the anticlinal walls of the cells are
undulate. The cell walls are thick (Figure 2F). Anisocytic
stomata are randomly scattered over the entire leaf surface
(Figure 2F). The subsidiary cells around the guard cells
are elliptic, lunate or arcuate, but vary in size (Figure 2H).
The leaves of Pararuellia glomerata are bifacial in
cross section. There is one layer of epidermal cells, these
with a thickened corneous layer on both surfaces. The
palisade tissue has one or two cell layers and is distinct.
Spongy tissue is inconspicuous. The cells of the entire
palisade layer and some of the spongy layer are full
of multifarious calcium oxalate crystals (Figure 2I-J).
Air chambers are under the stomata (Figure 2J). Many
articulated cuticularized hairs are on both leaf surfaces
(Figure 2F, G).
DISCUSSION
Pararuellia glomerata is distinct in the genus
Pararuellia. It is distributed only in poor soils in the karst
region of the hot and dry Hong He valley. As an adaptation
to the extreme environment, the plants have developed
many xerophytic characteristics, e.g. distinct palisade
tissue, inconspicuous spongy tissue, appressed epidermal
cells, hypogenous stomata with large air chambers, and
leaf surfaces densely covered with hairs, which decrease
transpiration and irradiation (Li et al., 2007b).
Calcium oxalate crystals in the leaf cells may aid in the
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survival of the plants. First, Pararuellia glomerata appears
to accumulate calcium (Li et al., 2007a). Second, calcium
oxalate crystals in the leaf cells of the entire palisade layer
and some of the spongy layer may provide support to
the leaves, without which the leaves may wither quickly
when dried (Franceschi and Horner, 1980). Third, calcium
oxalate crystals in the leaf cells may reflect light toward
photosynthetic cells, especially in shaded situations (Kuo-
Huang et al., 2007).
Pararuellia glomerata mainly depends on vegetative
reproduction. Few young independent individuals occur
in the field and in the botanical garden. Most individuals,
however, easily give rise to adventitious roots when
touching the ground and form new shoots, especially
in the botanical garden. Our observations indicate that
Pararuellia glomerata can flourish and may even become
invasive in the Kunming Botanical Garden.
Acknowledgements. We thankfully acknowledge Prof.
Hu Chia-Chi of Fudan University and Dr. Deng Yun-
Fei (South China Botanical Garden, Chinese Academy
of Sciences) for providing pertinent references. Mr.
Zhou Xiao-Long (Gejiu Administrative Bureau of Dawei
Mt. National Nature Reserve) was most helpful in the
filed survey. This work was supported by funds granted
to Yu-Min Shui from the Committee for Research and
Exploration of the National Geographic Society (Grant
No. 8288-07) and was partly supported by grants from
the Natural Science Foundation of Yunnan Province,
China (Grant No. 2001C0022Q), the Taxonomy and Flora
Special Foundation, the Chinese Academy of Sciences,
and the West Glory Project of the Chinese Academy of
Sciences to Yu- Min Shui.
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