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 23.70¢X. 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).

²yÁJ¦a¥Ö®ø

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 ¡Ñ 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 ¡Ñ 6-9 mm,

pinninerved, densely hispid, apex acute. Bracteoles linear-

SYSTemATICS

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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 ¡Ñ 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 ¡Ñ 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 ¡Ñ 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

CHEN et al. ¡X New species of

Pararuellia

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.

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 ¡K¡K¡K¡K¡K¡K...¡K...4

3b.

Rachis usually zig-zag, winged below nodes

¡K¡K¡K¡K.¡K...................................¡K¡KP. alata

4a.

Bracts oblong, elliptic or ovate ....................

..................................................P. cavaleriei

4b.

Bracts cordate or suborbicular ¡K¡K¡K¡K ....

.............................................. 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 Jeffrey¡¦s

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 ¡Ñ 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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Botanical Studies, Vol. 50, 2009

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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CHEN et al. ¡X New species of

Pararuellia

267