Table Of Content植物研究雑誌
J. Jpn. Bot.
67: 282-285 (1992)
Morphology and Chromosome Number of
Lobelia loochooensis Koidz.
Jin MURATA
Botanical Gardens，Fa culty of Science，Un iversity of Tokyo，
1842 Hanaishi-cho，N ikko，To chigi，32 114JAPAN
・
マルパハタケムシロの形態と染色体数
邑田仁
東京大学理学部附属植物園日光分園 321-14日光市花石町 1842
(Received on March 30，19 92)
Lobelia loochooensis，a ra re and endangered species of the Ryukyus，Ja pan，is redescribed based
on new observations of the morphology and chromosome number. In seed coat morphology it is
considered to be closely related to L. angulata，w hile gross morphology suggests ac lose alliance to
Hypsera sessiliflora. To settle this problem，a r evision of Lobelia and allied genera is needed.
Lobeliαloochooensis was first described by briefly mentioned (Satake et al. 1981). In June
Koidzumi (1929) on the basis of as pecimen with 1991，1 m ade field observations of this species on
flowers but without fruits. The fruits and seeds， Amami-Oshima 1s. and collected living plants，
therefore，we re not described. He considered this which were cultivated in the Botanical Gardens，
species to be close to L. affinis Wall. (=L. University of Tokyo，a nd used for chromosome
zeylanica L.) but different in having “all grabrous obs ervations
parts，pe dicels shorter than the leaves，th e leaves For chromosome observations，ro ot tips ob-
obscurely tridentate，m uch shorter petioles，t he tained from the cultivated material were pretreated
upper three anthers glabrous at the tip." 1n the with O.OIM 8hydroxyquinolineat 200Cf or three
・
infrageneric system of Wimmer (1953)，th is species hours，th en fixed in a3 :1 mixture of ethanol and
was placed in subsection Leiospermae of sect. gracial acetic acid，m acerated in lN HCl and
Hem伊ogonbut this was done solely based on the squashed with 1% aceto orcein.
inperfect original description by Koidzumi，wh ich The seed morphology was observed with SEM
was followed also by Hatusima (1971) and and compared with other species (Murata 1992).
Hatusima and Nackejima (1979). Walker (1976) A revised description of Lobelia loochooensis
revised the description based on the specimen in is given below. In Amami-Oshima，th is species
KAG，bu t the fruits and seeds were still unknown. grows on coastal slopes and is found in small bare
1n ar ecent Jap anese Flora，th is species was only patches surrounded by low bushes of Pleioblastus
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October 1992 journal of Japanese Botany Vol. 67 No. 5 283
linearis Nakai. This habitat is frequently exposed Ryukyu Is. 458 (1990). Type. JAPAN: Kumeshima
to strong sunshine，wi nd and rainfall. The prostrate Is. (The Ryukyus)，Sa kaguchi s.n. (holotype KYO).
and densely rooted stems，a nd the small，t hick Small perennial herb，a lmost glabrous. Stems
leaves with thick cuticles are well adapted to this prostrate，ra dicant，wi th branches to 9c m long，
kind of habitat. The laterally compressed capsular closely leafy. Leaves alternate，al most sessile; blade
fruits，de scribed for the first time in this study，ar e orbicular to broadly obovate to subobtriangular，
distinct from the symmetrical，su bglobose or sub- 5-7 mml ong and nearly as wide，r ounded at
cylindrical fruits of other Asiatic lobelias. In gross apex，u sually with a low tooth on each side，
morphology (Figs. 1-2)，in cluding flower mor- broadly obtuse to rounded at base. Flowers white
phology，th is species is very similar to Hypsera to pale violet，s olitary，a xillary on pedicel about
sessiliflora F.E. Wimmer described from New 1m ml ong or less (up to 2.5 mmw hen cultivated);
South Wales，Au stralia，an d differs from the latter calyx-tube 1m ml ong，t he lobes narrowly tri-
only in its larger size and fruit dehiscence.百lefr凶t angular，1. 5 mml ong; corolla 8-9 mml ong，
of Hypsera sessiliflora was described as appearing sparsely hairly inside，th e tube subcylindric，4 m m
to be ab erry. Although fruit dehiscence has been long，th e limb bilabiate，sp reading，th e lobes tinged
recognized as the most important character to with purple inside，o blong lanceolate，s lightly
separate Hypsera from Lobeliα，it may not be a longer than the tube; lower part of the filaments
critical character. In L.αngullαta，b oth capsules and united to the corolla，f ree part sparsely hairy，
berries are known to occur within the species staminal colum slightly shorter than the corolla，
(Moelino and Tuyn 19ω1)，wh ich sugg岱tsthat fruit the anthers violet，1 m ml ong，th e upper (posterior)
dehiscence mayv ary also in L. loochooensis so that 3g labrous，t he two lower (anterior) ones with
it mayb e conspecific or closely related to Hypsera papillae and as eta at the top. Fruit ac apsule，
sessiliflora. In seed coat morphology，L. loochoo- apically 2-valvate， subglobose，l aterally com-
ensis (Fig. 3) is very similar to and almost identical pressed，4 m ml ong. Seeds ellipsoid，re ticulate.
with L.αngulata，w hich suggests ac lose relation- Chromosome number: 2n= 14.
ship between them. The chromosome number Specimens examined: J. Murata，H . Murata
2n= 14 (Fig. 4) is the commonest in Lobelia and and M. Tabata. s.n.，Ja pan，Is l. Amami-Oshima，
has been found also in L. angulatα，(summarized 恥1iyakozaki，June 22，1 991.
in Murata，in preparation). Ont he basis of this
evidence，L. loochooensis is tentatively placed in This study was supported by a Grant on
the genus Lobelia，b ut further studies of Lobelia Scientific Research from The Tokyo Club. 1e x-
and allied genera are necessary to settle the press special thanks to Mr. Mitsutake Tabata of
systematic position of this species. Amami-Oshima for kind help in the field study and
to Mr. Fumio Shimozono of the Botanical
Lobelia loochooensis Koidz.，B ot.恥1ag.Tokyo Gardens，Un iversity of Tokyo，fo r maintenance of
43: 406 (1929); F.E. Wimmer，P flanzenr. 107 this rare endangered species. Thanks are also due
(IV276b):483 (1953); Hatusima，F l. Ryukyu 595 to Dr. David E. Boufford of Harvard University
・
(1971); Walker，F l. Okinawa 1009 (1976); Hatu- Herbaria for reading the manuscript of this paper.
sima and Nackejima，Fl ower. Ryukyu Is. 315，pl.
483 (1979); Shimabuku，C heck List Vasc. Fl.
284 植物研究雑誌第67巻第5号 平成4年10月
Figs. 1-4. Lobelia loochooensis Koidz. 1. L. loochooensis，c ultivated in the Botanical Gardens，U niversity
of Tokyo. 2. Flower，ve rtical section. Scale=5 mm. 3. SEM photograph of seed. Scale= 100μm. (from
Murata 1992). 4. Somatic chromosomes (2n =1 4). Scale =4 μm.
October 1992 Journal of Japanese Botany Vol. 67 No. 5 285
References 要 旨
Hatusima S. 1971. Flora of the Ryukyus. 940 pp. Okinawa-
マルパハタケムシロは琉球列島の久米島および
seibutsukyouiklkennkyuukai，Naha (in Japanese).
ト
一一一一一andNack吋imaK. 1979. Flowers of the 奄美大島にだけ分布する小型の草本であるが，従
Ryukyu Islands. 368 pp. Kodansha， Tokyo (in
来不明な点が多かった.絶滅危慎種として取り上
Japanese).
げられていることもあり，現地調査を通じて形態
Koidzu凶 G.1929. Lobelia loochooensis. In Contributiones
ad Cognitionem Florae Asiae Orientalis. Bot. Mag. および染色体数を調べ ここに再記載した.マル
Tokyo 43: 406.
パハタケムシロはオーストラリア産の Hypserα
Moelino B. and Tuyn P. 1960. Campanulaceae. Fl.
Malesiana ser. 1. 6: 107-141. sessilifloraに非常によく似ており，全体が大型
Murata J. 1992. Systematic implications of seed coat であることと果実が朔果である点で異なるに過ぎ
morphology in Lobelia (Campanulaceae -Lobe-
lioideae). J. Fac. Sci. Univ. Tokyo，II I. 15: 155-172. ない.サクラダソウ Lobeliααngulatαには朔果
一一一一(inpreparation.) Morphology and chromosome を持つものも液果を持つものもあることを考慮す
numbers of Lobelia angulata Forst.
れば，これらが同種である可能性もあり，今後検
Satake Y. 1981. Campanulaceae. In Satake Y. et a ，.lWi1d
Flowers of Japan III (Herbaceous plants - 討が必要である.マルパハタケムシロは奄美大島
Sympetalae). 149-155. Heibonsha， Tokyo (in では，海岸に面するリュウキュウチクに被われた
Japanese).
斜面の聞に点在する裸地に生えるが，このような
Walker E. H. 1976. Flora of Okinawa and the southern
Ryukyu Islands. 1159 pp. Smithsonian Institution Press. 場所は年々狭められており，まさに絶滅に瀕して
Washington，D .C.
いると考えられる.
Wimmer F. E. 1953. Campanulaceae -Lobelioideae II
Tei1. Pflanzenr. 107 (IV-276b): 1-813.
一一一一一1956.Campanulaceae -Lobelioideae 1T eil.
Pflanzenr. 106 (IV-276a): 1-260.
