Biosystematic Studies on the Genus Ixeris − （Compositae Lactuceae）1． Fruit Wali Anatomy and Its Taxonomic Implications

The Japanese SocietySooiety for Plant SystematicsSystematios

− − ISSN OOO1 6799 Acta Phytotax． Geobot．41 ： 43 60 （1990）

Biosystematic Studies on the Genus Ixeris − （Compositae Lactuceae）1． Fruit WalI Anatomy and Its Taxonomic Implications

− JaeHong PAKI and Shoichi KAwANo2

・一朴宰弘河野昭：ニガナ属（キク科・タンポポ連）の分類学的研究 1．果皮の解剖学的特徴とその分類学的意義

Abstract The mature fruit wall structures were invcstigated fer l80f about 20 傭癇 spec 三es − （Compos 童tae Lactucea ¢ 〉． Fourteen species had 10 costae ， nearly the same size in transverse sections and fbur species had − lO− − ， 5 70r 13 costae ， Fruit waU structures were divided intotwo ． maimypes ： wi nged type subdiv 蓋ded into Type I and Type ILA B G and ribbed type Type （，，），（ III ．Type I has thick 量ntercosta L repens Type II−A B and G have weU −developed costae ）（ ’）；，孟 ‘ePhala ， 1． debilis五 5 ‘oJo η γα L longirestrata 孟 ‘海 η 8 π 廊 and L tamagatvaensi ． The ribbed （ Poly ，静，，の type （Type III）has the least conspicuous costae （1． dentata and 工Oother species of sect ． Ixeridium）． In the winged type ， costae are f（）rmed by cell divisiens in the i nitial stage of costa1 tissue develop−

ment was ， but its development less conspicuous in the intercostal tissuc of ∬． rep 砌 50f Type L

In the ribbed type cQstae are of rather ， fbrmed by the disintcgration intercostaltissue ， than by − − cell divisions in costal tissue throughout pre and post fとrtil 重zation stages ． Based on the different fruit−wall types and ontogeneticprocesses as well ， as on karyological data， we suggest that l l species

ng sect w 量 r 量 belong ｛ to the ．Ixeridi ， th bbed achenes ， and largechromosomes with a basic number

of κ 富 7， can be distinguished from the rema ｛ning spec 互es ， which have wingcd achencs and s 皿 all

chromosomes and a bas量cnumber of κ 磊8。 New evidence conceming 丘u 董twall structures obtained ’ in the study does not supPort earlier scctional dassifications except fbr sect ． ChoTisls to present ，， which a single species L γ 8π∫ 三s referred ． resuhs suggest species referred sect ， ψ ， Our that the to ， Ixeriditrmwith ribbed ， achcnes alld large chromosomes with a basic number of x ＝7 represent ，

adistinct and thus should phylogenetic group ，， be placed in a separatc genus f｝om 勧ガ∬ ．str ．

Key words ： Gompositae−Lactuceae IxeriS Ixeridium wall anatomy ，，，fruit ．

and species The generic delimitation relat 量onships of 、rxeris and allied genera

Compositae ； tribe Lactuceae ， all of which are fbund f｝om north to south −eastern Asia （），

have been controvers 三al f‘）r many ． The Ixeris years genus ， as originally describedin

1826by CAssINI GAsslNI l 8263 KING and DAwsoN l on （ 975）based Ixerispoipcephala， c 圭rcumscribed only several species （DE CANDoLLE 1838）． The gcnus has also been

lDepartment of Botany ， Faculty of science Kyoto university Kyoto 606 ．，，， Japan Present address ： Departmeat of Biology Gollcge of Natural Science Kyung −Pook National ，， Unlversity， − Taegu 702 701， Korea． 2Depart 皿 t of Botany Faculty of Sc 量ence Kyoto Univcrsity Kyoto ，，， 606，Japan， and Instituteof Genetic

E 〔ology Tohoku Univers 三ty Sendai 980 ．，，， Japan

一 NII-ElectronicN 工工 Eleotronio Library Service The JapaneseSocietyJapanese Society for Plant Systematics

" Acta Phytotax. Geobot. Vol. XLI, Nos. 1-3

included in the broadly defined Lactuca (BENTHAM 1872). In more recent classifications, however, freris has been conEidered to consist either of approximately 20 species (NAKAi 1920; KiTAMuRA 1956, 1981; see also GRAy 1859) or ofabout 50 species, including some species of &opidiastrum, Paraixeris (NAKAi 1920) and even Lactuca (SfrEBBiNs 1937; ToMB 1977).

In these classificatory systems, achene morphology, the shapes ofthe involucre and coTolla, and the numbers ofvascular bundles in the ovary wall (STEBBiNs l937) have been used as key characters for defining these genera. According to KiTAMuRA (1956, l981), the species of ixen's are characterized by fusiform achenes with a mQre or less elongated beak, ten ribs or wings, and also a persistent bristled pappus. A related genus, ewopidiastram, also possesses fusiform achenes, but lacks a conspicuous beak. KiTAMuRA (1956) suggested, based on the Iife form, growth habits, leafmorphology, euter involucre size, head number, and pappus color, that llverds is divided into five sections: Chorisc's,

Rsende-chon'sis, indb-ixeris, Sobotixeris and .1beeridezam.

In these earlier studies, however, little attention was paid to the anatomical features efachenes. The only exception is a recent contribution by BELiAEvA and BoyKo (1980), in which achene morphology and anatomy of 13 species ofLactasa from the eastern region of the Soviet Union, including three 1]teris species (i.e., 1}veris ropens (=C`thorisds ropens"), L chinensis (--"freridium gramineum"), and L dentata (=:"1iveridium dentatum"), were critically investigated. They suggested that the achene wall structures are important and usefu1 fbr the delimitation of genera and for assessing species relationships. Thus, a more extensive study on fruit wall anatomy covering all the species in 11ven's and related genera became necessary in order to elucidate the exact status of these taxa. The purpose ofthe present study is twofbld: first, to describe the fruit wal1 structures of 18 llven's species, representing all five sections (KiTAMuRA 1956), that occur in Japan, Korea, Taiwan, Malaysia and New Guinea; second, to compare and discuss aMnities of

the species based on these results and other gross morphological as well as karyological

characters. For further understanding of the character states in fruit wall anatomy,

the ontogeny of the fruit wall was also critically examined in some representative species.

Material and methods

The eighteen ofspecies of1beeris (KiTAMuRA 1956, 1981) are listed in Table 1. Most of the fruits were obtained from herbarium specimens in the Herbarium of Kyoto University (KYO)s and some were collected from wild habitats or cultivated plants. Fruits were always soaked in or' fixed with FAA (formalin : glacial acetic acid : 50% ethanol=1 : 1 : l8), and then dehydrated through a t-buty1 alcohol series and'embedded

in Paraplast with MP 57-58 C for microtoming. Transverse and longitudinal sections cut at 8-12 psm were stained with safranin and fast green FCF, and mounted with Entellan.

NII-Electronic Library Service The JapaneseSocietyJapanese Society for Plant Systematics

Septernber, 1990 Acta Phytotax. Geobot. 45

Table 1. Species of ixeris examined and cellection sitesi).

Sectionfspecies2} Voucher specimens

Sect. C7lorisis (DC.) A. GRAy I. ropens (L.)A. GRAy Japan.Chiba: Tateyama,Hiroe17221. Hyogot Isl. Awaji, Kbnde 2J99.

Hoklcaido: Kitami,IVbrtthashil13e. Sect, lhab-ixeris KiTAM･

I. Palycophala CAss. Japan. Osaka: Takai,S;,to 3735. Kanagawa: Kawasaki,vazteshima16417. Sect, Psetedb-cherisis KrTAM･

J. debilisA, GRAy Japan, Aichi: Shinoiima, 1lakahashi2145. Mie: Mt. Suzuka, 24 May 1938, Okamoto s.n.. Korea, Chollanam-do: Dalri-do, Pak 780. L stolontfara A. GRAy Japan. Kyoto: Ooeyama, Mltrata 45066. Nagano; Mt, Shirouma, furuse 30. Ishikawa: Tatsunoguchi,Sugde 1022, Sect. Sbbelixeris NAI AI L longirostrata NAicAi (HAyATA) Japan. Isls.Bonin: Hahajima, Kbbayashi et al. 8gt1･ Sect. 1hreridium A. GRAy

I. tamagatvaensis KiTAMJ '8178. CMAKiNo) Japan. Nagano: Kami-ina, Mlatrata Matsumoto, Pak 920, Shizueka: Ohkawachi 17 Oct. 193!, Klatrosawa

s.n., L chinensis (THuNB.) NAKAi Korea. Taegu: Mt, Palgong, Pde 679-2, Republicef ahina (Taiwan). Hua]ien, Wenshan, S)Vimilu 12639. L dentata (THuNB.) NAKAr Japan. Nara: Yoshino, 7:sugaruet al. ee98. Nagano: Shiga-kogen,Pak900. L YAHARA Parva(KITAM.) Japan. Kagoshima: Isl. Yakushima, 1toatstLkietaL 59. L vakuinsularis YAHARA3) Japan, Kagoshirna: Isl, Yakushima, JteatstLki 329e. L transnekoensis KiTAM. (SAsAKi) Republic of China CI"aiwan). Nantou: Mt. Nehg-kao, Ttimura et al. 23348, Takao: Mt, Kanzan, Okamoto 9. L makinoana KiTAM. (M-ciNo) Japan, Hyogo: Akou,Pak 993. Mie: Igaueno,6June I937, Okayama s･n.J PeeplesRepublicofChina, Yunnan: Kumming, Kayama et al, 1413. L grctcitis (DCI.) STEBBINS Bhutan,EasternHimalaya: GonChungnang-Punakha, Hlzra et aL 15990 CI[-I). L laevigata paLuME) SaHuLTZ-Bip. ex Japan. Kageshima: Tashiro, 24July 1919, 7lashire, MAxTM. s. n.

Papua New Guinea. Western Highlands: Wabag Subdist. Hbagland et at. 6665 (L). L nen;aea (ZOLL. et MoRITZI) STEBBINs3) Malaysia. Sabah: Mt. Kinabalu, Sinith 557 (L). Papua New Guinea. Star Mts, W, Sepik, Vletcteamp 6577 (L), Lptesitla (MATr,) SviBBiNs3) PapuaNewGuinea. WesternHighlandsDist.: Mt. Kinkain, Vink l60sc (L). L sttbasaulis (KosiER, J) PA,K et KAwANo3) ,4) Papua New Guinea, East. Eastern Highlands Dist.: Mt. Wihelm, Shzith ANU li 129 (holotype: L!). L siamensis

i) All colloctions deposited at KYO unless otherwise noted. 2) Sectional classification fo1]ows KiTAMuRA (1956), 3) Species assignment in sections by the present authors, 4) LactLeca subaaaulis KosrER is transfbrred to the genus lbeeris as L szibticautis by the present authors tentatively.

NII-Electronic Library Service The JapaneseSocletyJapanese Society forforPlant Plant Systematics

ca Acta Phytotax. Geobot. VoL XLI, Nos. 1-3

Critical observations were made on mQre than five mature fruits per collection, in

which the endosperm was entirely absorbed and the embryo occupied the entire embryo

sac. The only exception was 1hreris parva, in which only sornewhat immature fruits were

by sc

sl lb 1mec exc

' 'glt't',･Wl･ - , /.., ..t, , ,zr.", vl'l ;:f,,l'i'1' ..;,;t-, Wim#fienFva'' -- - ,;.// 4C-lb t-,k,rw･--..ttin,ttt ... . ttt ,.tnytb., .tt ttt tt t tt ttttt t..t.t.'t'e. .. . lt ,.,, .tt.

Figs. 1-4. Fruit morpholegy and anatomy ofixeris, Fig. I: Scanning electron micrographs ofmature ffuit ofL debilis, Fig. 2: Diagram il]ustrating a transverse sectionofL debilis. Fig. 3: Diagram illustrating the structure of a single costa of I, debilis. Fig. 4: Longitudinal section of costa ef L ropens. cos, costa; em, embryo; exc, exocarp; lb, iibriform fiber cells (4C) ; inc, intercosta; mec, mesocarp; sl, fiber-selereid cells (4A, B); sc, seed coat; vb, vascular bundle. Scales equal 2oo pm in Fig. 1 and 10 psm in Fig. 4.

NII-Electronic Library Service The JapaneseSocietyJapanese Society for Plant Systematics

September, 1990 Acta Phytotax. Geobot. 47

available. Terminology: For a precise comparison with other related genera, the fruit wall structures of 1]eris were described basically fbllowing the terminology used by LAviALLE (l912), who

studied the development from ovary to fruit ln the Compositae. All 1beeris specles

ribs which examined have achenes with mere or less conspicuous longitudinal (Fig. 1), are anatomically termed costae (Fig. 2). Although the ovary is inferior, the fruit wall structures were described in terms of exo-, meso- and endocarp, hs in the case ofa fruit wall formed by a superior ovary. Mesocarps of the costal and intercostal walls are compesed of the two different types of is formed ncarby fiber cells: libriform fiber, narrow and long (l50-259 pam long), which the tip of the costa with thick and pitted walls; and fiber-sclereid with helical structures, broad and short (50-150 psm long), which forms most of the costal and intercostal walls (Figs. 3 and 4). '

Results

Mature fruit wal1 anatomy All species examined had 10 costae (with rare exceptions) which were nearly equal in width, as seen in transverse section. Histologically, these species further sharcd

a crushed endocarp and a one cell-layered tanniferous exocarp, as well as one cell-layered

seed ceat with spiral thickening. However, they showed a marked diversity in the

mesocarp with respect to the position oflibriform fiber and the thickness of fiber-sclereid in the costal and intercostal wall. On the basis of the histoiogical difference found in

the mesocarp, the fruit wall structures of the species examined are to be divided into two

and ribbed type main types: winged type (including Type I and Type II-A, B, a) (Type III). In Table 2 all the data on the morphology and anatomy of the species, as well as on the fruit wall type, are compiled.

1. Wingedtype

Type I: thick, This type was found only in 1)ceris ropens (Fig, 5), and is characterized by having ixerisrapens had the non-degenerated intercostal tissue. Of all the species examined, largest fruits, particularly with respect to body length (59.0-69.9 psm) and width (iO.O- 14.5 ptm) . Costae are 185-250 pm thick in transverse section. Librifbrm fibers are positioned at the tip ofthe costa, forming a bundle composed of50-62 cells. The underlying tissue consisted of fiber-sclereid with helical structures 7-10cells thick. The intercostae are 68-121 ptm thick in transverse section, and the mesocarpic tissue is composed of fiber- sclereid 5-7 cells thick. BELiAEvA and BoyKo (1980) described the intercosta as formed

NII-Electronic Library Service The Japanese SocietySooiety for Plant SystematicsSystematios

弼 Acta Phytotax ． Geobot ． − VoL XH ， Nos 。1 3 （胴F 哨。つ。冩【一一 H g ．＜く的 O O 一 H 一一 ≧ F ，， − − − ，閏目閏り暮 H H 置岡目昌 HH ＝目昌鬥昌冨り目目目同【目象唱卜 5 田 ‘ 冨

匂踏 ob4 o 』毒卜 HI 『う £ 沿 IO 劣亠亠亠 98 田，【＝コお8 Z ρ ．旨唱． 9 占 Qo ーコ曷 21 爲 2 馨一 − ー − I oD さ器雪。・罍り喟り

山斜 “ う嶋 O αう O 屮 o ◎ め N 寸緜ぴっう摩う O18 o う 86 o 歯［旨゜り 9 鬪讒ひ｝ 6 「ぞー鑰 1 マー lO ー 1 。ーー IO 1 Ioo Io 1 甲り尋靄覊 α9 三 6 α⊃ っ輯咽斡国蕊【門国 ⊆ ヨ［［霞ド邸襲殴鵠贈の・も』の。』實 O 寸鳴蝉ぜ斜 o 毎 ℃ 詮〒「 1 ¢ 団「畧墨卜 § ・，め αう cu め d 「霞 − ・． O 』三「 ⇒ 毛乞お 8 覊蝦。。。ぴう O 卜 6 （ 8 O ト O 888 聯器 8 嬲舗 8 ！ぎ膏翁 ° う凹湿斧 − 9 旨マ撃 llll 鑒 11ilI ｝塵りミ頃 O 宀め嘱） QD 8 ト職驢驢』一＝竺黠雛呂職 § ←

寒 O O 鳴 O O 頃嶋 O O O O O O O O O O 鴫．．．．．．．．．．．．．．．．．，（ O O αう α弓 QoI N 伽っ 0 αリ α う啓ら，う論毫 dq ［の ◎う磐錦黷黛一州三。莞［ b◎ 〒 IO IO IO IO マ IO マ〒。 6 O 6 己あ 6 6 ゐ亠置［竈）日．．．．．、，．『．．．．O ．．，O ．N ．頃卜 O め O oo 咽め oコ o り蔚昼 2 二＝望＝。

O O § ．．．『．． O ．鴫．ゆ．『 O ．寸．ぴっ．O ．O ．゜う．O ．頃．◎コ．ヨ（ O 守 O 尊う 0 創困彈 06 °亀專自靄需壽騎 eq6 寸苫翁霧冶』。 lO 叩叩 IO IO マ雫・。凶ム O あ咽謬鐸．．。 6 鳴己よあ O O 邑凶角［）．．．，．．．．．．．．、．． °ら α 、鳴 α う °り，餮め q “う ω 囚禹斜 8 雷爵爵孚満鈎ヨ靱紹（。咽包ゆ．目 O O め O O 塗自囂函 O O O ［ O 0◎ O O O 尉）．．．．．，．．．．．．．．．。．． O 卜 αうト OOIO “り O ＜蹇碧 210 尊卜魯ヨ省 810D專写守 8 謝孚瞻 9 寸。 1 ？ママ − IO ℃ ー o め蔚山 O 助告 oF 曽日 6 O 6 己ゐ宀亠ら亠。）．．．．．．．．．．．．，．．．．．【 ° 、 O ° うぴ「 § ρ 耄． 8 °うミ享斜尊 9 爲躊享寸爲め °う 6 等爵等個目毎

図 2 鴎 O 09 α「 q巨 O qっ 09 ト嶋 O o∋ O 凶・・号．．．．．．．．．．．．．，．．．．唱留．（ロっ助寸嶋卜 Oq り O Q り卜．＝つ O O トき臼省毫［讀 8 で日 IO IO ーーー Io 〒 Io9 。出亠喟凶 6 め 6 亠 o よ的一 ⊇ のめ屋頃角 ≧9 ．．．．．．．．．．．、．．．．．．象 O O oD 鳴鳴創ぴ剛うう 05 笛 oり守 06 αう鐸う O 喝 α っ遷冒三 ℃ 莓。霎捻唱掴の隔哨 h 聾咽黥筒．馨ミ。蠧ミ密 8 螽 h § § § 肖曇 § ミ § ミ § 巉ミ § ミ著 9 壽ミ庵岱篭 § 魅醤聴同謹〔量聡 § 匣 § 鳶羮寒 § 電 § ミ邸【蓄ミ § 湘ぎ電鴇 § 愚雪養羃， § 、き動説ミミ隷 § ミ遷芯ミ噂ミ § h § 。舞暮譽 § 竃ミ琶電芯 § 喟竜 § § ミ韓刊。 § ミ § § ミ煽竜ミ融 § 鬟 N リ h き．，ミ，ミ．．潟．噌．．．．．．．栖，ミ．ミ．． ∪ N さ竃．丶．丶．丶丶丶丶丶丶嘱りり．．丶丶丶丶丶、、丶」扇 ← 回おのののちぢぢ o 8 8 AAA o o 【 No うののののの

一 NII-ElectronicN 工工 Eleotronio Library Service The JapaneseSocietyJapanese Society for Plant Systematics

September, 1990 Acta Phytotax. Geobot. 49

by thin-walled parenchyma cells in ixeris rapens (="(]:horisis ropens:'), but in the specimens examined mesocarpic cells are thick-walled with fibrous thickening and not parenchymat-

ous, at least at maturity.

Type II-A

This type is seen in 1beerisPoipcophala (Fig. 6) and L debilis (Fig. 7), and is characterized by its conspicuously thick costae in transverse section.

rk x' O -

.ggll.!>}y.'s-,S",as.'

"eiifil

W W - ' @ d

g"- - ,

Figs. 5-10. Transverse sectiens of fruits of keris. Fig. 5: L tepens. Fig, 6: L polycqphala, Fig. 7: L debiles. Fig. 8: L tongiTeslrata. Fig. 9: L stolonijbra. Fig. 10: L chinensis. All scales equal 100 "m.

NII-Electronic LibraryMbrary Service TheTheJapaneseSocletyforPlantSystematlcs Japanese Society for Plant Systematics

50 Acta Phytotax Geobot Vol.XLI, Nos.1-3

aostae range from 140 to 276 pam thick Libriform fibers are iocated at the tip of

the costa and form a bundle composed of 28-45 cells The underlymg fiber-sclereid tissue is 3-5 cells thick Intercostae are O-25 ptm thick in transverse section, and have only 1-3 (I debzlzs) or O-1 (I polycophala) fiber-sclereid layers

Type II-B This type occurs in llveraslongtrostrata(Fig 8) and J stelonijlera (Fig9), and is

characterized by its conspicuous but thinner costae than m Type II-A

The thickness of costae is 65-170 ptm Libriform fibers positioned at the tlP tO

tat ' bl-l ttt S: ltl l l- tv ri"vade#lt" tttt.1-=.di t lva -t-tra t"u tm t ' 1 T-.cr/ p gill?ii @"it:rv/l n 'ntttv t"la: wttti v :k-numa - in-fi:1-uri"t tlwlVtu zat ini.n iasmzt LS.tcfi- di t}m :tdi vta:lva-1ri nilny arw t-lrtt a yalttl tm tt -T lie: "-l i u ln tFt ni"I et:= ' L e lm ' - nt lv .4 . fi: hel

ulp- ts"r F -t tva -

t ttptt ' idit="-sl -rintutt ldi '1-tn "srvevnu-fietfge .:ny..ltlvv e"xk- lwopuinul tt-ms '. -t/t "Z:th ts T nt pttin leent Ll-tt ' ' uns o l::ge:I:l:sutl mpgwku- -tl jl mee'tt nd- - tin tin flet inve V - rm Lav . :- umwini rcglffuen t" I"w-l " uSl t t-ts in C -r t ua le:tu tfiri.l lX 'lt- bUI ttzaFt . =- ffF"I- t rv Iv a gw l W.:S#iL= fiLor -vediniinl ' u-/"ei" :. ul ma- t .IPila rkberslm=IFenv"ug btt .l t mu ua mm r av" lt i umuLl fin -/ le FzaS M:trm tt um th- tt v/ su- ku n anv , . "nyllnfitye Itt. stu- - 'rw v ge ... T.t -tt di1di" - IY nv"suth- nyor-.. tt --r '"l"t-J#"vaewme:s-pmpMMrmrmr :l ummann :t .g":mawn ttil IMljnft{ fi -vein}MInf i 'ge - t= tS=lpslwealjuak" w ' "- thwor umA diXmakdiX me tttt di ""rgfi 'ty uaevawm"wntt nym. fi za( l nN. -t.zzmsevevps nvt-L -m l rv -n:IE:::Ias ee IZ za tt ng va1ttrvthenMM 11fl m l=a lvafitr vr- itTttt Any-s' u= tht-y w- Y as.r ri tht dirm t-I . I-tM--nv/ntirm#-uSny. m--uanm.-.Mt t evtt tnv ma ;-tu.tl ' mlalimeL - t swu ' l:mpwn 'tttIVt MnvS Utt LWt ' leV tl nA wtnt rv tny

hl:'vawige,:s:xinl;L'`':t.Ag".':ev:th:.iua":'". ..-" :':nv:lr i- , ttv

Figs 11-16 Transverse sections of fruit of 1beerts 11 tamagawaensis 12 dentata

Fig 13 I .vakuinsulans Fig 14 I Parva FigFig 15 ll trans?tekeens:s FigFig 16 Il maktnoana All scales equal 10e "m

NII-Electronic Library Service The JapaneseSocietyJapanese Society for Plant Systematics

September, 1990 Acta Phytotax. Geobot. 51

middle of costa are 23-56 in number, and the unclerlying fiber-sclereid tissue is 2-4 cells

thick, Intercostae are 8-15 pam in thickness and contain 1-2 cell-layers offiber-sciereid.

Type ILC: This type is seen in Ibueris chinenst's (Fig. 10) and L tamagatvaensis (Fig. 11), and is characterized by its less conspicuous costae than those in Type II. aostae are 30-65 pam

in thickness. Librifbrm fibers occupy nearly the whole costa, and number 24tr33.

The underlying fiber-sclereid tissue is only 2-1 cells thick, which is in agreement with the

ebservations of BELiAEvA and BoyKo (1980: I]teris chinensis (=C`llveridium graminettm") ).

- @

･N -

{ @

.t--･ '

Figs. 17-22, Transverse sections of fruit of lkeris. Fig, 17: Lgneitis. Fig. 18: L lcrevigata. Fig. I9: L nemaea. Fig. 20: L pusitla. Fig. 2!: I. stcbacaalis. Fig. 22: L sianrensis, All scales equal Ioe "m.

NII-Electronic Library Service TheTheJapaneseSocletyfor Japanese Society for PlantPlantSystematlcs Systematics

52 ActaPhytotaxGeobot Vol.XLI, Nos.1-3

wtunm"- diLnlf-lre

rrmwnvesinz=w=nfnikleeeeljF:gme1=nfi":camawmiImmwewh:e=nvemaditgvaivavaha-x=ewvaum?y,i"k'.:

s:i

ntthvee

::rdiZWISn'su

fi1v

Figs 23-30 Transverse sections of fruit of ]buens showing development of the fruit wall Fig 23 Young ofl pistil polycophala Figs 24-27, and 29 Fruit in past-fertilizatien stage 24, I ropens, 25, J I Pelycaphala, 26, tongrrostrata, 27, I tamagadiaensts, 29, I laemgata Figg 24-26 Fruitin embryo stages 28, I glebuJar pelrcophala, 30, l taemgata ac aerenchyma, vb vascular bundle AII scales equal 50 psm

NII-Electronic Library Service The JapaneseSocietyJapanese Society for Plant Systematics

September, 1990 Acta Phytotax. Geobot. 53

Intercostae lack the fiber-sclereid layer.

2. Ribbed type

Type Ill: This type is characterized by its least conspicuous costae as fbund in Lxeris dbntata, I. ]akuinsutaris, L Parva, L transnekoensis, L makinoana, I. gracilis, L lnevigata, L Mgmasa, I. pusilta, L subacaulis, and L siamensis (Figs, 12-22). Costae are only 20-95 "m thick, and are formed principally by libriform fibers that are about 6-58 in number. Sclereid-fibers are not present in either costae or intercostae, although BELiAEvA and BoyKo (1980) described that the intercesta of 1]ceris dentata (=``1]feridium dentatum") as comprising i-3 parenchymatous cells. As far as the specimens examined in the present study are concerned, L Parva possesses 12 costae, L Pusilla 5-7 costae, L subacaulis 12-13 costae, and L sianzetzsis IO-I2

costae, instead ofIO.

0ntogeny of the fruit wall

Despite a great diversity in mature fruit wall structures, all the species had similar pisti1 wall structures in the younger stages. Indeed, the pistil wall at an early stage with an evule primordium is 6-12 cells thick and had five small vascular bundles, but no conspicuous costae wcre seen (Fig. 23). Later, at the post-fertilization stages, a thick aerenchyma developed in the inner side ofthe fruit wa}l in all the species (Figs, 2`I-30),

The formation of costae is apparently difft]rent in the species with winged type from

those with ribbed type. In the former the costa development resulted from cell divisions

in initial costal tissue, but they were less conspicuous in intercostal tissue of I, ropens with

Type I throughout pre- and post-fertilization stages (Figs. 2428). In the latter, the

costae were formed by disintegration ofintercostal tissues, rather than by cell divisions in

costal tissues (Figs. 29 and 30). An accompanying degeneration of the aerenchyma, as well a$ the cell diflerentiation into two diflbrent types of fibers, libriform fiber and fiber-

sclereid, in costae (and in intercostae in some species), eventually resulted in the mature

fruit wall structures of Types I-III.

Discusslon

DifTbrentiation of fruit wa!1 structures

Fruit wa]1 structures of 18 Species were examined in the present study, of which 14 I)ceris species preved to possess 10 costae, with the exceptions ofL Parva with 12 costae, L Pttsitta with 5-7 costae, L subacaulis with 12-13 costae, and L siamensis with lO-12 costae.

Costae were of nearly the same size in transverse sections of the frtrits. All the species

showed a marked diversity in the mesocarp with respect to the position oflibriform fiber and the thickness of fiber-sclereid in the costai and intercostal wall. On the basis of the

NII-Electronic Library Service The JapaneseSocietyJapanese Society for Plant Systematics

54 Acta Phytotax. Geobot. Vol. XLI, Nos. 1-3

,P".,'-.:-'woLg,'''';"=.-.l1

Ie III '1td , l

'.--'LE'''e""..--･ss-t

{'L 1 j llm[mMEEG 11!IF, II-C II-B ' II-A '

Figs. 31. Diagram showing two main types (Type I-III) of rnature fruit wall structures emphasizing costa and parts ofintercesta. Libriform fiber cells dotted; fiber-sclercid celts striped.

histological differences found in the mesocarp, the fruit wall structures were divided into two main types (Fig. 31): winged type (including Type I, Type II-A, B, C) and ribbed type (Type III). Diflkirent ontogenetic processes involved in costa formation strongly suggest that the fruit wall structure ofthe ribbed type (Type III: L dentata, Lyakuinsularis, L parva, etc.) has obviously evolved from a different, now unknown, ancestral group.

Indeed, only in the ribbed type are the cestae formed due to the degeneration of inter-

costal tissue, instead ofcell divisions in initial cestal tissues as in winged types. This view / is also well suppert6d by the karyo!ogical data, i.e., species with winged achenes possess

small chromosomes with a basic number of x=8, whereas those with ribbed achenes

have large chromosomes and a basic number o{" ec::-=-8 (PAK and KAwANo in press). Ameng the frllit wall structures ofwinged types (TyPes I, II-A, B, C), Type l (seen in ixeris ropens only) is quite distinct in having a much thicker intercosta. Indeed, in Type I the intercosta is 68-121 gtm thick, whereas in Type II it is less than 25 psm thick. Only

in Type I did the fruit wal] exhibit cell divisions in the initial intercostal tissue in later

ontogenetic stages; these were not observed in any other types. Such a specific fruit wall

structure of Type I (llteris mpens) appears to represent a specialized type in the genus 1hreris. Its characteristically thick intercostae obvieusly represent a derived structure

adapted to dry sand dune habitats ofthe seashores. ･

The fruit wall structures of Type II-A, B, C are more or less similar. The general

NII-Electronic Library Service The JapaneseSocietyJapanese Society forforPlant Plant Systematics

September,1990 Acta Phytotax.Geobot. 55

trend seems to be from Type II-C to Type II-A by a gradual increase in the degree of

costa development, based on the outgroup comparison and chromosomal evidence.

Paraixen's, which is regarded to be one ofthe outgroups ofkeris, is known to have the same fruit wa}l type as II-C (BELiAEvA and BoyKo 1980-P. denticulata and P. sonchijblia). The somatic chromosome number of L debilis with type .II-A is 2n==48. TAKEMoTo (!952) postulated that it might be an autohexaploid derived from I. stolonijlera (2n==16), on the basis of cytological and morphological evidence.

Relationships within ]ixeris:

Since the mature fruit wall structures designated Type I-III are consistent within each species or group of species, they are useful as additional evidence in considering species re}ationships within the genus. In Table 3 all 18 species belonging to five difirerent sections were compared on the basis of fruit wall structures as well as other characters of

diagnostic value that have been used fbr sectional classification (KiTAMuRA 1956). The character state distribution of fruit wall structure is in agreement with only one section,

Chorisis (J. ropens only), and does not perfectly agree with four other sectional delimitations. ixeris ropens, the only species of sect. enorisis, has always been clearly distinguished from

other species by ibs palmate radical leaves and characteristic large invelucral size, and even has been placed in its own genus, enorisis (DE CANDoLLE l838) or as a monotypic section Chorisma of a separate genus, Lactuca (BENTHAM l872). BELiAEvA and BoyKo (l980) supported a distinct position of 1iveris ropens (=-"Chorisis rapens") from both 1beeris and Lactuca on the basis of shorter beak and thicker intercosta. Likewise, ixerds ropens

･･-････-･･･ secLCborisis

･secLlndo-ixeris '1/

;.･-sect.Pse;tdo-charisis ･--sect,Sobotixeris

IxXDL ･･･- -･i････- ･･･ secL ixeridiutn

I, - .: pygmaea(?) l. pttsitla (?) : : . - 1. stthacautis (?) - - - l- I. situnensis (?･) - -t.."".H"......

Fig. 32, Diagram demonstrating the inter-relationship amonginfrageneric groups based on the basic chromosome numbers and fruit wall structure of bceris Csensu Pak and Kawano).

NII-Electronic Library Service The Japanese SocietySooiety for Plant SystematicsSystematios

− 56 Acta Phytotax ． Geobot ． Vo1 ．XLI ， Nes ．1 3 一ゴ．

ぐ＜国繭 O O ，， − − − ，一一一一 H 一一一回 H 團 H 目毳目將 H 目閏目一一一一一一目 H 類 H H 困回口 H 目口箏・【冖一剛［［。。。の一類一一邸邸幡帽罵尉罵』回切秘』。切 b 。』』』』』臥馬山函 “ 霞貫旨實日日罠鵠のののの畠日爨ののの 5 5 5u 5 °。卜卜，（ 6 ¢ 斜゜コ °。卜卜冨．尉日言 o ◎ 鮒卜卜・． 09 03 09 05Q Q コ（〔 o ． o ，c ． Pt， c 。 o ．、° 8 専 O 一守等寸嘗謂ヨコ “ ． Pt，e ．a ，e ．衰 o 冑雪雪雪寸ヨ “ ［曷曷尉一門一．， O 晦叡．．（言守 § 。う雪［邸ち（゜。

も閏汐 o りり＝口 ⊆ 口錯 q 儲 q 口口〇） u 』曁刊 9 一一 9 3 ε 一絶刷 ≧ き ≧ ≧ 診汐 ≧ ≧ ≧ ≧ 8 一〇三ヨヨヨヨ諳 o o o o 遷く自 8 8 8 9 』 9 』』」 9 ：〇 ≧ ＞ ≧ 勢〇巴「 P 「羣 ≧ ≧ き薗葭国国頗笛餡葭ロ自 ≧ 9 寄ε 窒 O O O O ト ° 噂 q も・。【黛【冖雲［自一掣芝遷 bo 守醐 g 9 9 2 990 9 ．ー − 19 自唱眉頃釁 O …齷鬯．乞掣』（慧旨袰 … − （爲鼕・。身 9 ℃ もでも唱も唱勹 ℃ 州 2 髢刃冨彫彫刃它り萄 o o o o o o お呂（』 b b bo b 。萄）O 琴 o ◎ 。。 ρ ゑ』 ρ 』』』』ぬ臼ぎ聾盆累零 ρ 巳寡琶。 b。 ε £ 石石川咽 ε 覊碧 £ 農覊 β £ 磊毳覊喟麗毒亀助。のく日削。 ≧ ≧ き ≧ ≧ ≧ 彡出属出国出出函餌出国畄喋お．躍（〔〇一 QD 〇 O 彊自聾』帰。 °コ引＝一一鋼禦黛 92 ＝ 9 o 里 819 震− 震冩鵠日ト慧 IQ − 1 IO ーーーー i20 IoD Io く旨，込ト一のゆ口 § o 6 ユ頃 QgOI ⊇ 旨【島酎倒一一創 N £ ）呂嘱、婁名名【日招帽自＾竈袰・、・・・、、 £ 頃四鍬臥 Pt ＞〉 Pt Pt ＞〉〉〉〉 Pt ∩ 窪も自 a 口 q 口 qq 口昌 q 自 § ．咢き邸） ≧ 邸団邸縄邸鋸邸邸帽膩 ⊂N ed 養智濤 ok oo 一周 ε § o ミ帽語芝随閏芝薯昆嵩芝凄 Σ 芝 Σ 署署亠芝自ヒ謂恩 §謡，。簧（・・ § 。四も obO v o ゜。閏霞名』亀電掃り聾 D ◎ ． N 蝿』 L 』鈩へ（2 咽昌邸邸雇雇鬟驪餐雪薩弓鵞礬萼墾．壱宕の a 露 en のの c “．のもQ gQ の m 、略。 A の AA 日日臼の詰（ ≦ o o o 2 蓴饗綻） ε 9 晋鵞嶌嵐』。． 0 g 謡［層竈堯・。〔価』』』暫 9 篭 N 盤 3Q 3p 。ミ図圏 ε 蕁琴隸邸鵠買舅 8 三。蕊咽唄嘱嘱暗＄ o I 喟齷＆」』鴛ヨ当亀。雲』。署 q 曁冨壽ミ 2g ¢ 聴 oZ 8 。葺コつ旨ε ε 脅，昌陰賃『首 O 2 ・・誘寓 Zg 認くくくく H コ護日嵩汐琴くこ o o ω 。爵 g 3 8 g ε 8 g 8 g 図 8 く自邸禽量冨邸幽 o 譲』讐套【鬥響譜蠡謹現）儲『 08 08 08 ．臼胴氤 3 5 p 5 ロヨ（ § 箇り滋 8 詩 89 崙詫ヨヨ為・り壱琶壱壱ヨ碧碧．ε ぞ＆目口口口口旨 £ （畧畧圏冨掃霽 … ［訂 8 雨駑嚼震鼠巴巴巴邸酪邸 “ 巴巴・り盛 9 （避尉畄【叨山日 u 。ののの謁日日日口コ日のの £ 8 讒）コ 9 冩・，讒 §）雪夥＝餮瓮臣一 o o ）ぐ』 2 自音 § 葱＆蝦義強 h ≧ （哨醒． 8 召四毎話丶 δ q 自旧屑［ぎ叢き一 o o o 一伺 U θ U 一一一（ ⊇ 匕［ 9 岩り 90 も弓り弓りり房ぢ鬟で． o おり 8 o o 8 函田鳴』 o で o で o °・儒 9 』雪』田』曾」』鬢』髪田 2 篝壽昌 O 謂あ臼あああ国国国国国螢国国国国国国畄餌．．［【き鼠畜な去＝胃罸罵罵罵罵冩冩府霊需聴邸罵罵府ミ戛ゴ咽咽咽嘱嘱嘱嘱咽 ε 實＄爵自口口口口口口口で暑（石罵嘱屑履智旧山黛 § 5 目口口 £ ．罵． 8 目 5 宕 5 岩。諺器器蠧 o 琶鵠 5b8 5 。 ρ 書目』』』』』』、 5 一』む q o o o む o む b b お b おむ o ε ．帽の〇旨 ε 画＜角山角角角角角角氏角角角角画角慧。 Q 亳 §痛室頸で a 邸稔認量曇鴇（肩蚤冠卜翼羮 § 遷罨卜罷噌岩 9 轄 ℃ b ，ミ日 § り蛙謹三鵡遷遺愚．。羮翁ミミ略。・。話 § ミ鴨 § B § o § ・・践煢 − 回ミ嵩 § § 罵。暮の碁藁避 § でこ養＆ミ船ぎミ書轟遷、， § § 彊 § § § 。日黐ぢ（養 § 恩竃ミ墅蕁慧心 § き H8 § 魯 § 鷲蕊且藏鴨ミ § § 竃』。盞脯 § 』き § も § ミミ竜喬 § 鞠、謹蛍ミミへミ蟻署。 § 婦 § ．§ ．ζ ．．潟．霞．．．．．．．．．．り 8 羽．丶．」、丶、．丶一．h 丶崎丶丶賊丶『丶丶丶丶の Σ 舅ぎ∩ の 8 50 ちちぢ AA A （ A an oc Pt りっり o o 8 − 騨ののののの

一 NII-ElectronicN 工工 Eleot ［ onio Library Service The JapaneseSocietyJapanese Society for Plant Systematics

September, 1990 Acta Phytotax. Geobot. 57

is distinct from other 1bueris species in its larger fruit body sizes (see Tabte 2). However, except for the thick intercestae (and also the larger fruit), which are considered to have been developed as a result of adaptation to a maritime sand dune habitat, as stated above, other gross morphological, anatomical and karyological characters all support its inclusion in ixeris as a distinct section.

Section lado-ixeris, containing only Ihreris polycophala, is defined by its fiaccid annua]

habit as well as by a combinatien ofother morphological features such as, e.g,, sagittate cauline leaves and alate achenes, It is clistinguished from section Rseudo-cherisis (L debilis and L stolonijbra) by many attributes, including growth habit, lea{S shape and involucral size. In the latter section, 1]veris debilis (2n=48) has been considered an autohexaploid derived from I, stelonij?ra (2n== 16) on the basis of morphological and cytological evidence (TAKEMoTo 1952). However, in the character of fruit wall structures, I)teris debilts shows a similarity to I, Poipcophala, rather than to L stolonijbra, in sharing well-developed costae designated as Type II-A, 1hreris longirostrata, which is endemic to the Bonin islands, is assigned by NAKAi (1920) to its own section, Sobotixeris, fbr the sole reason that I.

tongirostrata is diilbrent from his two other sections, sects. Chorisis and Ettixeris, in showing

both an erect and sto]oniferous growth habit. It is still uncertain how a hexaploicl species, fueris debigis, has evolved, but the evidence from fruit wall anatomy suggests close

relationships between I. debilis and I. poipcophala, as well as between L stolonijlera and L

longirostrata. A careful re-examinations of conventional diagnostic characters, as well

as critical comparisons of other characters, seem to be necessary fbr revealing the true

interrelationships among those four species. The remainder of the species examined can be referred to section lbeeridium in a classical sense. This section was first clefined by a combination of5- to IO-flowered capitulum and sordescent pappus (GRAy 1859); later, KiTArvtuRA (1956) regarded its auriculate or linear cauline leaves and less conspicuous ribs as additional distinguishing

features ef diagnostlc valuc. Hewever, th ¢ evidence from fruit wall anatomy clearly shows that two species, 1)ceris chinensis and L tamagarvaensis (both :["ype II-C), are conspicuously diflbrent from eleven other species (all ribbed typc). Despite their superficial similarities, the cestae or ridges of the fbrmer group are formed by cell divisions in the initial cestal tissue, as in all species with winged type, while those of the ]atter are formed

by the degeneration ofintercostal tissues. The distinctness ofthe species with ribbed type (Type III) from all other species is also supported by karyological data and external morpholegy (i.e., number of ligules per head and color of pappus; see Table 2). Thus, in the species with ribbed type (Type III) the basic chromosome number is x=7, with all chromosornes much larger (the chromosome numbers ofL gracilis, I, Mgmuea, L Pusitla, L subacaulis, and ,L siamensis are not known yet), whercas in all species with winged type (Type I, II), the basic chromosome number is x=8, with conspicuously smaller chromosomes (see IsHiKAwA 1921). In addition, two types represent the diflerences in number ofthe ligules per head and also in the color ofthe pappus; that is, the winged type possesses

NII-Electronic Library Service The JapaneseSocietyJapanese Society for PlantPlantSystematics Systematics

Acta Phytotax. Geobot. Vol. XLI, No$. 1-3 su tt

whereas the ribbed type has 5-12 ligules 15-30 ligules per head, and a whitish pappus; The only exception is I, siamemsis; and the taxonomic per head, and a brownish pappus. ' two species of section status of this species is uncertain. There is no doubt that the have cleser relationships with the species of 1bueridutm, ixeris ehineiLsis and I . tamagawaensis, BABcocK et al. on the other sectiens, rather than with those ofsect. 1beeridium. (1937), in 61 species of the Crepidinae basis ofan overall examlnation ofchromosome morphology ixerisdentata x;7) has a closer included 8 species of Ibeeris, suggesting that (with x=7) of rather than with other species of rescmblance to sect. 1hreridopsis(with oropis, 1hrerts (with x=8). as well as Based on the difllerent fruit wall types and ontogenetic processes, of sect. 1)teridium,with ribbed chromosome morpholegy, we suggest that 11 species from the remaining achenes, and the basic number x=7, can be distinguished groups, ofx==8. We believe that which have winged achenes with a basicchromosome number which referred to as sect. 1)ceridium, the species with ribbed achenes (x=7), have been ' thus should be in a separate represent a distinct phylogenetic greup, and placed genus, on our new i.e., lxeridium. The nomenclatural treatment based findingspresented genus ' submitted). will be in a forthcoming and KAwANo, MS in this paper givcn paper (PAK '

Acknowledgments

KoyAMA, H. ToBE, and We would like to express our sincere thanks to Drs. H. suggestions N. HARA and all of our col!eagues in the laboratery for their valuable during

are to P. BAAs and C.-I.PENG the course ef this study. Our cordial thanks due Drs. Directors and Curators of KYO, L, MAK for collecting the fruits used in this study , and to ' ' to Dr. K. and TI for their kind loan ofherbarium specimens. We are grateful WATANABE

chromosomal data of his work. We thank Dr. for sharing an important unpublished critical reading of our W.F. GRANT, the GeneticsLaboratory,McGill University,for . manuscrlpt.

Literature Cited ' BABcocK, E. B., G, L. STEBBtNs,JR. and JENKiNs,J. A. 1937. { hromosome and phylogeny in some genera ef the Crepidinae. Cytoiogia, FtliiiJub. Vol.: 188-210. structure of the achenes ofthe Far East BEi,iAEvA, T. M. and E. V. BoyKo l980. Morphologo-anatomical Bot. Zurn. SSSR 65(3): 409-413 spccies of Lacttecas L. (Asteraceae) in relation of their systems. (in ･ Russian). in: BENm{AM, G. and HooKER General Plantarum vol. 2 pp. BErgmAM , G, 1873. Cichoriaceae. J.D. ' 50tt-533 London: Reeve. ' aAssiNi, H. 1826, liveris. in: KiNG, R.M. and DAwsoN, H,W. 1975 (eds.), Cassinion Cempositae York: cellected from the Dictionnaire des Sciences Naturelles. pp. 517-518 and pp. 1238--1239. New Sentry. 7. DE CANDoLLE, A. P. !838. Cichoraceae. in: Prodromus Systematis Naturalis Regni Vegetabilis, Vol, pp. 74-252 Paris: Treuttel et Wurtz. GR]fir, A. 1859. 0n the botany ofJapan. Mem. Am. Acad. N,S. Vr: 396-398. Bot. Mag. Tokyo 35: 153-158 IsHiKAwA, M, 1921. 0n the chromesome efLaetuca (A preliminary note).

NII-Electronic Library Service The Japanese SocietySooiety for Plant SystematicsSystematios

September ， 1990 Acta Phytotax． Geobot． 59

（in Japanese）・ − KERR ， A ． F ． G ．1935． Contribution to the flora of Siam ． Bull． Misc ． Inform ．； 326 335 ．

KITAM 【凪 A s ・1956・ Gomp ・ sitae ・Mem ・colL scL Kyoto Imp ・univ ． ser． B ， Japonicae， pars Quinta ，，， Bio1− 23 （1）： 11卜 123．一．！981 ． Wild F 】owers of Japanesc Herbaceous Plants（including dwa subshrubs ） Vo1，3 （Sympetalae ）． Tokyo ． He 三bonslla （inJapanesc ＞． Kos R ．1976． The Gompositae of New Guinea V ． B 正umea 23 ： 163−175．肥， J LAvlALLE ，1912． sur le developpement de Povaire en 丘7uit chez les〔】omposees 、．， P Rcchcrches Ann Sci．

Nat ， Bot ，15 ： 39−152 ．

NAKAI T ．1920、 NQtulae ad et Koreae 23． Bot． Mag ． Tokyo 34 ： 141−158．， plantsJaponiae ’ ONo ， M ． and Y ． MAsuDA 1981． Chromosome number of some endem 至c species of the Bonin Islands IL − Ogawawara Res ．4 ： 1 24。 − − PAK ， J．H ． and KAwANo ， S．1990， Biosystematic stud 孟es on the genus Ixeris〔Compositae1．actuceae ）II． Karyological analyses ・（】ytologia （in press）． − and l990． Biosystematic s 糖 dies on the genus Ixeris（Compositae Lactuceae ） IV ， Taxanomic treatments ． Acta Phytotax． Geobot．（in press ）． PENG ， C ．−1． and G ．一（】．正｛su l978． Chromosomc numbers in Taiwan Compositae ． Bot ．8ulL Acad ． S｛n ． − 19 ： 53 66 ． − STEBBINs G ． L ．．1937． Gritical notes on tlie Ixeris．， Bot ．75 ： 43 51．，，JR genus J ’ TAKEMoTo T 1952 Gomparative studies on Ixeris stotonifera 2x and Ixeris aPonica 6x Bot Mag ，．．（） J （）．．． − Tokyo 65 ： 164 167． − ToMB A ．S ．1977． systematic review ． In： HEYwooD V ．H ．HARBoRNE ．B ．and TuRNER ，， Lactuceae ，，， J

B ．． the Compositae VoL 2． London ． Academic Press． L （eds ）， The Bioめ gy and Chemistryof ， −・肌：．． Flora ． 388 ． Tzv Ev ，N ．1964．Ixeriditrm．In KoMARov ， V L ， URSS Vo1 29， 393pp YAHARA ， T りH ． OHBA and ．1． MvRATA 1987． Taxonornic review of vascular plants endem 量c to Yakushima − Island， J． Tokyo Univ ． Fac ． ScL Sect． IIL 14： 69 ll9 ．

ンニ摘要本研究は，キク科タポポ連のなかで主として東アジアに分布するガナ属並びにそ

ルーの近縁属の種の類縁関係と分類学的帰属に関する再検討を行ったものである。従来このグ

NAKAI 1920 STEBBINs 1937 KITAMuRA 1955 1956 っ一っプには，（），（），（，）らによてないし三

つっの属が認められていたが，形質の分化が複雑であるところからその評価は研究者によて著一一ていっっこののしく異なり，必ずしも致した見解が得られなかた。従て，連研究では，従

来導入されていなかったそう果の解剖学的並びに核学的形質の綿密な比較萌究を通して形質の

づこ進化傾向を明かにすると共に，種間の類縁関係の把握に努め，これらの新知見に基いての

っ群の分類学的再検討を行た。一 4 部から構成されている論文の第論文である本報では，ニガナ属における果皮の内部構造

の分化を解剖学的及び発生学的手法を用いて明らかにすると共に，併せて行った核学的諸形質

PAK and KAwANo in ののてについてべ（， press）詳細な比較研究結果と総合し得た結論述た。

mesocarp − まず，における fiber sclereid と librifbrm fiberの形態，その発達度合と組織の分

をるこによってこののニガのの二つの布比較研究すと，れら形質分化がナ属植物そう果型，す

winged type ribbed type 一こになわちとによく致するとが明、らかにされた。さら，発生過

っ程を詳細に追跡することによて， winged type では子房壁組織に部分的に局在した細胞分裂

っによて翼形成が引き起されるのに対し， ribbed type では発生途中段階から維管束間の細胞

の退化によって肋状の突起または稜が形成されることが明らかとなった。

このの一ニ結果は，染色体諸形質の観察結果ともよく致する。すなわち，ガナ属（広義）にーは x − 8 x − 7 の二つのループる 8 のグルプでは染色体基本数がとグが存在すが，基本数が

一 NII-ElectronicN 工工 Eleotronio Library Service The Japanese SocietySooiety for Plant SystematicsSystematios

− ．．． 60 Acta Phytotax． Geobot Vo1 XLI ， Nos 1 3

のでまた相的な染色サイズが型であるのに休止核形態は prochromosome type あり，対体小

ルー type でる PAK and in 。対し，基本数が 7 のグプは diffuse で大型あ（ KAwANo ， press）

x − x − ののののの分化これらの 8， 7 の植物群は，そう果内部構造分化や他外部形態上諸形質

っ量dium x − 7 のともよく対応することが明らかになった。従て， Ixer 節に帰属する大型の染

っつる TzvELEv 1964 めていに Ixeridium 色体と稜をもた果実をく 11種は，（）も認るよう属

PAK and KA − に含めることが妥当であると考えられる。命名に関連した新見解は第 4 論文（

。 WANO ， in press）の中で整理されている

村田源：カヤツリスゲ京都府西舞鶴に現れる

でのべていいつかの福井の若杉孝生さんから送られてきた西舞鶴港採集晶をしらると，く外

．。．． − 来種にまじってカヤッスリスゲ Carex bohemica SGHREB ．があった（1990 6 24 T WA

TANABE No ．30631）．

ヨーロパベのカヤッリスゲはッから東シリアにかけて欧亜大陸北部に広く分布しているが，一よの口にだに知られいる産植物の日本では北海道の釧路や阿寒湖畔，おび本州河湖付近け稀

いこつたといわれてつである。カヤッリスゲの名は姿がカヤツリグサに似てるとろからけられ・：のス図図北の植物の会 1960），北村村田いる。図は吉川純幹日本ゲ属植物譜第 3 巻 149 （陸

・：スが小山原色 El本植物図鑑草木編 m ， 66図版 448 （保育社 1964）にある。ゲ属は大部分多

い一でる年生の草木で占められてるが，本種は年生あ。

バノセンンサ Bidens 日本では湖畔の砂地にだけ現れるという特異な性質があり，ホソダグ

肌モのにっ parvi且ora W D ．でいわれているように，大陸からカ類のような渡り鳥体種子がく

カラフトモメンヅル Astrag副 us schelichovii ついて移入したのではないかとも考えられるが，

TI 皿 cz ．が日光中禅寺湖畔に遺存していたと考えられる例もあるのでカヤッリスゲの場合も森

林の発達が揶制される湖畔の特殊な砂質の立地に遺存していると考えた方がよいのかも知れなには士口湖大浜浅い。山梨県から昭和 57年 3 月に発行された山梨県植物誌 197 頁富山（河石，

三ッの地にえとある川，山中湖手野，峠，黒岳），湖辺湿生，稀，。

今回西舞鶴港で発見されたのはソ連からの物資の輸入にともなって新しくシベリア方面から

のによると日氏が西をおとつれ移入してきたものと思われる。発見者若杉氏， 6 月 24 同舞鶴港

いシベアわるを上だた時，ソ連国籍の貸物船とおぼしき船が接岸しててリ材と思れ木材荷げ中

スいのいのないの壁近ったという。そしてカヤッリゲが生えてたは，古湿地とは関係埠頭岸

ヒコガゼショくに砂が積んであるところであるという。同じ日に若杉氏は同所でメウイキウ

ハ et マバニ L マルポリイ Eleocharisavata RoTH RoEM ・ saHuLT ，ツ Juncusbufonius ，（）ンジン 1．inum stell roides PLANGH ．などを採集しておられる。一の舞鶴近辺は旧日本海軍軍港で，第二次世界大戦が終結するまでは般の人達が自由に立入

ったとしてでりできなかたところである。近年西舞鶴港は日本海に面し良港京都府舞鶴市も整

めの々になシベリア面からのしい化備が進られており，今後ソ連と貿易が益活発れば，方新帰

植物の渡来が考えられる。

一 NII-ElectronicN 工工 Eleotronio Library Service