全 文 ：植 物 分 类 学 报 44 (5): 516–522(2006) doi:10.1360/aps050030
Acta Phytotaxonomica Sinica http://www.plantsystematics.com
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Received: 23 February 2005 Accepted: 1 July 2005
Supported by the Yunnan Provincial Government through an Award for Prominent Contributions in Science and Technology to
Prof. Wu Zheng-Yi in 2001, No. KIB-WU-2001-03.
* Author for correspondence. E-mail: .
Chromosome numbers of four genera in the
Dryopteridaceae
1,2LU Jin-Mei 1LI De-Zhu* 1WU Ding
1 (Laboratory for Plant Biodiversity and Biogeography, Kunming Institute of Botany, the Chinese Academy of Sciences,
Kunming 650204, China)
2 (Graduate School of the Chinese Academy of Sciences, Beijing 100039, China)
Abstract Chromosome numbers and reproductive types of six species of four genera in the
Dryopteridaceae, i.e., Leptorumohra, Lithostegia, Phanerophlebiopsis and Cyrtogonellum
were investigated. The chromosome numbers were n=41 in Leptorumohra quadripinnata,
2n=164 in Lithostegia foeniculacea, 2n=82 in Phanerophlebiopsis neopodophylla, ‘n’=123,
and 2n=123 in Cyrtogonellum fraxinellum, ‘n’=123 in C. caducum and 2n=123 in C.
inaequalis, respectively. The chromosome numbers for all the genera but Leptorumohra were
reported for the first time. The results indicated that the chromosome base number of all the
four genera was x=41, a common number in the Dryopteridaceae. The reproductive type in
Cyrtogonellum is apogamous whereas in the other three genera it is of the sexual
reproductive type, which is widely found in ferns.
Key words Dryopteridaceae, Cyrtogonellum, Leptorumohra, Lithostegia, Phanerophlebiopsis,
chromosome number, apogamy.
The family Dryopteridaceae is of cosmopolitan distribution although with a strong
concentration of genera and species in the temperate regions of the Northern Hemisphere,
particularly in the hills and mountains of eastern Asia (Ching, 1965a; Tryon & Tryon, 1982;
Kramer, 1990; Wu & Ching, 1991; Wu, 2000). Ching (1965a) founded the family
Dryopteridaceae based on Dryopteris Adans. However, the Dryopteridaceae has been
variously circumscribed ever since. The family was treated under an illegitimate name,
Aspidiaceae, by many authors (e.g. Pichi-Sermolli, 1977), and it was more broadly defined to
include Athyriaceae, Woodsiaceae, Lomariopsidaceae, Nephrolepidaceae, Onocleaceae, and
Tectariaceae (Tryon & Tryon, 1982; Tryon & Lugardon, 1990; Kramer, 1990). However,
recent molecular phylogenetic studies using rbcL sequence data revealed the polyphyly of the
Dryopteridaceae sensu Kramer (1990) (Hasebe et al., 1994, 1995; Wolf et al., 1994; Pryer et
al., 1995; Sano et al., 2000), although phylogenetic relationships of genera in Dryopteridaceae
were not well supported. Furthermore, there is no cladistic analysis of morphologic and
cytotaxonomic data, which made the phylogenetic relationships within the family more
unresolved. Any sound subdivision of it could be very provisional without further studies on
morphological, cytological and molecular data.
Cytological and reproductive studies may provide very useful information for the
phylogenetic studies of various groups of organisms (Raven, 1975). Chromosome counts can
promote our understanding of phylogenetic relationships at different taxonomic levels. Some
cytological observations of the family Dryopteridaceae have been reported since 1950s
(Manton, 1950; Mitui, 1965; Hirabayashi, 1969; Tsai & Shieh, 1985; Lovis, 1977; Löve et al.,
1977; Shimura et al., 1982; Wang & Xia, 1984; Wang, 1985; Weng, 1990; Kato et al., 1992;
No. 5 LU Jin-Mei et al.: Chromosome numbers of four genera in the Dryopteridaceae 517
Yatskievych, 1996; Lu & Cheng, 2003). Chromosome counts published previously for genera
of the family indicated that the chromosome base number for these genera was x=41.
However, there is still a blank of chromosome counts in some genera, especially in those from
eastern Asia. One goal of this study is to increase the sampling size of the genera for
chromosome counts in the Dryopteridaceae, as part of our phylogenetic analyses combining
morphological, cytological and molecular evidence. For practical reason, the classification of
the Dryopteridaceae in the Flora Reipublicae Popularis Sinicae (Wu, 2000; Kung, 2001) was
followed herein.
1 Material and methods
Living plants (Table 1) were collected in the field in Yunnan Province and Chongqing
Municipality, China, and cultivated in the Kunming Botanical Garden, Kunming Institute of
Botany, the Chinese Academy of Sciences. Voucher specimens are deposited in the
Herbarium of Kunming Institute of Botany, the Chinese Academy of Sciences (KUN).

Table 1 Materials and chromosome counts of four genera of Dryopteridaceae
Taxon Chromosome
number
Spore
Number1)
Locality Voucher
Leptorumohra quadripinnata
(Hayata) H. Ito
n = 41 64 Dali, Yunnan
(云南大理)
J. M. Lu et al.
(卢金梅等) 112 (KUN)
Lithostegia foeniculacea (Hook.)
Ching
2n = 164 64 Gongshan, Yunnan
(云南贡山)
J. M. Lu et al.
(卢金梅等) 155 (KUN)
Phanerophlebiopsis neopodophylla
(Ching) Ching ex Y. T. Xie
2n = 82 64 Guangnan, Yunnan
(云南广南)
J. M. Lu et al.
(卢金梅等) 176 (KUN)
Cyrtogonellum fraxinellum (Christ)
Ching
‘n’ = 123,
2n = 123
32 Xichou, Yunnan
(云南西畴)
J. M. Lu et al.
(卢金梅等) 002 (KUN)
Cyrtogonellum caducum Ching ‘n’ = 123 32 Xichou, Yunnan
(云南西畴)
J. M. Lu et al.
(卢金梅等) 001 (KUN)
Cyrtogonellum inaequalis Ching 2n = 123 32 Mt. Jinfoshan, Chongqing
(重庆金佛山)
J. M. Lu et al.
(卢金梅等) 047 (KUN)
1) Number of spores per sporangium.


Root tips were treated in 0.002 mol/L 8-hydroxyquinoline solution for 3–4 h before
being fixed in Carnoy’s solution (95% ethanol : ice acetic acid=3:1) for 4 h. They were
washed in 95%, 70%, 50% ethanol and distilled water, and hydrolyzed in 1 mol/L HCl at 60
℃ for 9–12 min, and then stained in 2% aceto-orcein for 1–3 h and squashed in 45% acetic
acid. Meiotic chromosome counts were gained from sporocytes at late diplotene or diakinesis.
The suitable pinna (on which the sori slightly became yellow) was fixed in Carnoy’s solution
using the usual aceto-carmine squash method (Manton, 1950). Mitotic and meiotic cells were
examined and photographed using a Zeiss Axiophot-II photomicroscope.
To determine the reproductive type, number of spores per sporangium was counted.
According to Walker (1979), there were two reproductive types in ferns, i.e., the sexual
reproductive type with 64 spores in a sporangium, and the apogamous one with 32 spores.
2 Results
The chromosome photographs of meiotic and/or mitotic materials of six species in four
genera are shown in Figs. 1–7. These chromosome counts (Table 1) are all reported for the
first time.


Acta Phytotaxonomica Sinica Vol. 44 518



Figs. 1–7. Chromosomes of four genera of Dryopteridaceae at meiosis and mitosis. 1. Leptorumohra quadripinnata,
n=41. 2. Cyrtogonellum caducum, ‘n’ = 123. 3. Lithostegia foeniculacea, 2n=164. 4. Cyrtogonellum fraxinellum, ‘n’=123.
5. Cyrtogonellum inaequalis, 2n=123. 6. Cyrtogonellum fraxinellum, 2n=123. 7. Phanerophlebiopsis neopodophylla,
2n=82. Scale bars=10 µm.


No. 5 LU Jin-Mei et al.: Chromosome numbers of four genera in the Dryopteridaceae 519
2.1 Leptorumohra quadripinnata (Hayata) H. Ito
The species is distributed in Yunnan, Guangxi and Taiwan, China and also in Japan. The
material from Dali, NW Yunnan, had 41 bivalents at meiosis (Fig. 1). Sixty-four regularly-
shaped spores were observed per sporangium. Thus this species is a sexual diploid.
2.2 Lithostegia foeniculacea (Hook.) Ching
This is a Himalayan species, distributed in India, Sikkim, Myanmar and southwestern
China (Xizang and Yunnan). The material from Gongshan, NW Yunnan, was proved to be a
sexual tetraploid having a somatic chromosome number of 2n=164 (Fig. 3), and producing 64
spores per sporangium.
2.3 Phanerophlebiopsis neopodophylla (Ching) Ching ex Y. T. Xie
This species is endemic to China, occurring in Guizhou and Yunnan. The material from
Guangnan, SE Yunnan, had 82 chromosomes in the mitotic cells (Fig. 7). The spores are
regular in shape. The species is a sexual diploid, with 64 spores in a sporangium.
2.4 Cyrtogonellum fraxinellum (Christ) Ching
This species is distributed in Yunnan, Guizhou, Guangxi, and Taiwan, China. The
material from Xichou, SE Yunnan, was proved to be of apogamous reproductive type, with
the same chromosome number of 123 both in meiosis and mitosis (Figs. 4, 6), and with 32
spores in a sporangium. Thus this species is an apogamous triploid.
2.5 Cyrtogonellum caducum Ching
This species is distributed in Chongqing, Guangxi, Guizhou, Sichuan, and Yunnan,
China. The material from Xichou, SE Yunnan, had 123 bivalents at meiosis (Fig. 2).
Thirty-two regular spores were observed in a sporangium. Thus this species is an apogamous
triploid.
2.6 Cyrtogonellum inaequalis Ching
This species is distributed in Chongqing and Guizhou, China. The material from Mt.
Jinfoshan, Chongqing, had 123 chromosomes in the mitotic cells of root tips (Fig. 5).
Thirty-two regular spores were observed in each sporangium. Thus this species is an
apogamous triploid.
3 Discussion
The chromosome numbers for the genera Lithostegia, Phanerophlebiopsis and
Cyrtogonellum are reported for the first time. These results indicate that the chromosome base
number of all the three genera is x=41, a common number in the Dryopteridaceae. The fourth
genus, Leptorumohra, is an eastern Asian genus of four species. Leptorumohra miqueliana
(Maxim. ex Franch. & Sav.) H. Ito was cytologically studied by Hirabayashi in 1969. He
reported there were intraspecific polyploids in this species in Japan, including diploid, triploid
and tetraploid. From the result of the present observation, L. quadripinnata is a sexual diploid.
However, polyploidy may be found in this species after observing more populations.
Lithostegia is a monotypic genus based on Aspidium foeniculaceum Hook. (Ching,
1933). The particular morphology of indusium makes Lithostegia very distinct in
Dryopteridaceae. The phylogenetic relationship of Lithostegia is not in consensus (Nayar &
Kaur, 1963; Pichi-Sermolli, 1977; Kramer, 1990). The base number of x=41 as revealed here
provides cytological evidence in support of its placement in Dryopteridaceae.
Phanerophlebiopsis is a genus of nine species endemic to China, mainly distributed in
Guizhou, Hunan and their neighbouring regions (Ching, 1965b, 1987; Xie, 1990b). The
present study has revealed that this genus has x=41, strongly suggesting that it should be a
member of the Dryopteridaceae.
There are two different reproductive types, the sexual type and the apogamous one, in
Acta Phytotaxonomica Sinica Vol. 44 520
ferns (Manton, 1950). About 10% of the world’s (Lovis, 1977) and about 13% Chinese (Kato
& Nakato, 1999) fern species are apogamous. The reproductive type in Cyrtogonellum is
apogamous while in the above-mentioned three genera it is sexual, a reproductive type
widely found in ferns. Cyrtogonellum is a genus distributed in limestone areas in
southwestern China to northern Vietnam, comprising about eight species (Xie & Li, 1989;
Xie, 1990a). Apogamous ferns are mostly triploid (Lovis, 1977; Walker, 1979). From our
previous (Lu & Cheng, 2003) and present observations, it seems that there is a similar
tendency of apogamy in conjunction with triploidy in Cyrtomium Presl and Cyrtogonellum.
All the three examined Cyrtogonellum species and eight apogamous Cyrtomium species are
triploid (Lu & Cheng, 2003; Lu et al., 2006). These species are all distributed in limestone
areas with relatively dry condition and infertile soil. In such a habitat, seasonal shortage of
water may significantly affect the reproductive processes in ferns. If water availability is low,
fern sperms cannot move freely to achieve fertilization successfully. However, apogamy can
avoid this shortcoming, as it does not need water for fertilization. This may explain that
apogamous ferns can occur in drier and colder habitats than those with only sexual
reproductive type. Apogamy may have evolved in Cyrtomium and Cyrtogonellum as a means
of adaptation to degraded habitats during their evolutionary processes.
Acknowledgements We would like to thank Prof. LU Shu-Gang of the Yunnan University,
to Dr. GAO Lian-Ming and Ms. JIAO Yu of Kunming Institute of Botany, the Chinese
Academy of Sciences for their help in collecting materials, to Prof. WANG Hong and Prof.
GU Zhi-Jian of Kunming Institute of Botany, the Chinese Academy of Sciences for their kind
help in experiments.
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Acta Phytotaxonomica Sinica Vol. 44 522
鳞毛蕨科四个属的染色体数目
1,2卢金梅 1李德铢* 1吴 丁
1 (中国科学院昆明植物研究所生物多样性与生物地理学重点实验室 昆明 650204)
2 (中国科学院研究生院 北京 100039)

摘要 报道了鳞毛蕨科的4个属(毛枝蕨属Leptorumohra、石盖蕨属Lithostegia、黔蕨属Phanerophlebiopsis
和柳叶蕨属Cyrtogonellum)6种植物的染色体数目及生殖方式。其中柳叶蕨Cyrtogonellum fraxinellum
‘n’=123, 2n=123; 离脉柳叶蕨C. caducum ‘n’=123; 斜基柳叶蕨C. inaequalis 2n=123; 四回毛枝蕨
Leptorumohra quadripinnata n=41; 石盖蕨Lithostegia foeniculacea 2n=164; 长叶黔蕨Phanerophlebiopsis
neopodophylla 2n=82。石盖蕨属、黔蕨属和柳叶蕨属的染色体数目为首次报道。结果表明这3个属的染
色体基数和鳞毛蕨科中其他属一样均为x=41。细胞学证据支持将石盖蕨属、黔蕨属置于鳞毛蕨科的处
理。本文还发现柳叶蕨属与贯众属Cyrtomium的一些种一样, 具有无融合生殖方式, 而其他3个属仅具有
在蕨类植物中较为常见的有性生殖方式。
关键词 鳞毛蕨科; 柳叶蕨属; 毛枝蕨属; 石盖蕨属; 黔蕨属; 染色体数目; 无融合生殖