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ISSN OOOI-6799 Acta Phytotax, Geobot. 49 (1): 1-17 (1998)

A Taxonomic Study of Asarum magacalyx F. Maek. and

Related Taxa (Aristolochiaceae) Distributed in and Adjacent Areas of

TAKASHI SUGAWARA

Department ofBiology, fuculty qf Science, Shinshu Uhiversity, 3-1-1 Asahi, Mdtszamoto, Nagano 390-8621, Jopan

Abstract. This study makes clear the taxonomic dispesition of unusual plant$ of Asarum (Aristolochiaceae) in Niigata Prefecture and adjaeent areas previously referred to as Heterotrqpa yoshikawai, an illegitimate name. Chromosomes and morphological ieatures of 66 populations, including populations of Asarzttn megacalyx and A. ikegamii, which bear a close resemblance to the plants in question, were examined. Morpholegical and karyological investigations revealed that Heterotrqpa yoshikawai was obviously different from the above two species in karyotype, shape of the calyx tube and reticulatien of the ridges

within the calyx tube, Itherefore reco.um'ze it as a distinct species, and validated it with the name Asarum yoshikarvae. Additionally, the unusual plants from the nerthern part of Niigata Prefecture and southwestern are recognized as a new variety of A. ikegamii, and deseribed as A. ikegamii var, fojiinakii. In eonnection with the taxonomic

consideration, relationships among the three species are also discussed.

Key words: Aristolochiaceae, Asatum, lleterotropa, karyotype, morphological variation,

new taxa;- taxonomy

Received December IZ 199Z accepted Flebruary 25, i998

Asar"m is a diverse genus of perennial herbs distributed in eastern Asia, Europe, and North America. In the broad sense, more than 40 species have been attributed to Japan (Ohwi, 1975; Satake and Momiyama, 1982). Although various intensive studies (e. g. Maekawa, 1933, 1934, 1968; Hatusima and Yamahata, 1988) have tried to clarify and enumerate the Japanese species, the taxonomy of Japanese Asarum is still ' incomplete. In 1996, Mr. H. Fujimakj informed me of the occurrence of unusual plants of Asarum' in the northern part of Niigata Prefecture and southwestern Yarnagata Prefecture. Based on his information I made field examinations and found that the plants occurred widely along the . In this area two species of Asarum, A. megacalyx and A. ikegamii (=Hizterotropa ikegamii), were already known (Yuhki, 1992; Ishjzawa, 1996). These two species are commonly characterized by their broadly ovate leaves and elongate rhizomes, and distinguished from each other by flower size (Maekawa, 1988) and chromosome number (Ono, 1960). The unusual plants in question appear to be intermediate between A. megacalyx and A. ikegamii in flower size, and have been attributed

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inadequately to one or the other of these two species. In the same region, in the western part of Niigata Prefecture and the eastern part of Toyama Prefecture, an illegitimate name, Heterotropa yoshikawai (Ono, 1960; Maekawa, 1964, 1968), has been assigned to plants regarded as being closely related to Asarum megacalyx (Maekawa, 1964, 1968; Hasegawa and Tomitori, 1981), but the status of these plants has remained unclear. To clarify the taxonomic disposition of the unusual plants and of Heterotropa yoshikawai, and to determine the limits between Asarum megacalyx and A. ikegamii, morphological and karyological studies of population samples of these plants was conducted. Based on the results I am describing one new species and a new variety.

Materials and Methods

Plants of Asarum examined in this study grow in broadleaved forest usually dominated by Ctimellia iqponica Thunb. subsp. rttsticana (Honda) Kitam., euercus crisp"la Blume, and thgus crenata Blume, and open their flowers in March and ApriL They are easily distinguished from Asarum fauriei Franchet, distributed in the same area, by their broadly ovate to triangular leaves. In this study 66 populations were selected to cover the range of distribution as far as extensively as possible (Table 1; see also Fig. 9). The number of samples from each population is shown in Table 1. Flowers were fixed in FAA and were then used for measurment of floral parts. A few specimens representative of each population were deposited in the Herbarium of Shinshu University (sHIN).

TABLE 1.Co]lection sites, sample sizes, voucher specimens, and chromosome numbers.

Somatic chromosome No, Population Locality CSampte size)i)Veucher specirnei numbe;.(Sample size)2) 1 TOY. AsEihi-machi. Miyazaki (10) T. Sugarvara 970401 24 (3)24 2 NII. Itoigawa C, Oka (3) T. Sugawara 97Z)424 (2)24 3 NII, Itoigawa C. Kajiya (12) T. Sugawara 970417 (2)24 4 NII. 970404 Itoigawa C. Rendaiji (12) T. Sugaveara (2)24 5 NII. No-machi. Nakao (le) Z Sugaveara 970419 (2)24 6 NII. Jyoetsu C. Nakanomata (15) T. Sttgaveara 970425 (3)24 7 NII, Jyoetsu C, Mt, Kasuga (7) T, Sugawara 970301 (1)24 8 NII, Jyoetsu C. Mukabashi (10) T. Sugawara 9703{M (2)48 9 Nll.Jyoetsu C,Torigakubi (7) T, Sugawara970418 (2)48 10 NII, Yahiko-mura. Yahiko (15) N. Flijimaki 951201, 970201 (2)48 11 NII, Tochio C. Nakanomata (3) T, Su.aawara & N. Fay'imaki 970446 (2)48 12 NII. Sumen-rnura, Suhara-togeI(3) T Sugawara & N. fuiimaki 970451 C2)48 13 NII. Sumon-mura. Suhara-toge II (4) 71 Sugawara & N. Fay'imaki 970450 Cl)48 14 NII. Sumon-rnura, Fukuyama (5) T. Sugawara & N. Fiijimaki 970445 (1)48 15 NII. Tochio Hanzogane C. (4) IV. Fiij'imaki 9,70439 (1)48 25 NII. Irihirose-mura, GomisawaI (5) T, Sugawara & tV. Fay'imaki 970447 (2)48 31b NII. Kamo C. Kootsu T (10) T, Sugawara & TL Kuhara 970414, (3) 9ro429

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TABLE I. Continued.

Sornatic chromosome No. Population Locality (Sarnple size)')Voucher specimen number (Sample size)2)

384355NII, Kanose-machi, Arasawa (7) Af, ,F2ofimaki 970304 48 (1)48 FUK. Nishi-aizu-machi, Kami-nojiri (2) N. Fu,iimaki 970306 (1)48 NII, Kanbayashi-mura. HirabayaEhi (10) T, Sugauara & N. Flijimaki (2) 9ro312 62a YAM. Oguni-machi. Ecchuzato I (4) Z Sugawara, N. Pojimaki & TL 48 (2) Kuhara 970408, 97043J 64 YAM, Oguni-machi. Kaneme (3) T, Sugauara, IV. thijimaki & T. 48 (2) Kuhara 970415

656616171819NII. Sanpoku-cho. Gatsugi (5) N. Fojimaki 960506 48 (2)48 AKI. Kisakata-machi. Nakanozawa (4)Y, Horii 9704531 (1)24 NII. Yunotani-mura, Mugurasawa (3) 71 Sugawara & N, Fng'imaki 970448 (1)24 NII. Yunotani-mura, Ooyu (10) TL Sugawara & N. Fag'imaki 970452 (2)24 NII. Yunotani-mura, Komanoyu (13) T. Sugawara & N, Ftij'imaki 970442 (4)24 NII. Sumon-mura. Suhara (15) T. Sugawara & Tl Kuhara 970411, (2) 97V412 20 NII. Sumon-mura. Nishimyo (15) Z Sugawara & N. Ploj'imaki 970444 24 (2)24 21 NII. Irihirose-mura. Kakinoki (5) Z Sugawara & Ai. Plei.iimaki 970449 (1)pa 22 NII, Irihirose-mura, SuesawaI(10) 71 Sugarvara & N. Foj'imaki 970443 (2)24 23 NII, Irihirose-mura, Suesawa II (12) Z Sugawara & N, Fng'imaki 970440 (1)24 24 NII. Irihirose-mura. Motakesawa (12) T. Sugauara & N. Fng'imaki 97044J (2)24 26 Nff, Irihirese-mura. Gomisawa II (12)T, Su.aawara & Tl Kuhara P705Cl2 (2)24 27 NII. Shimoda-mura. Osoba(10) N, Fay'imaki 970438 (2)24 28 NII, Shimoda-mura, Kasabori (12) Ai, Fay'imaki 970436 (2)24 29 NII. Shimoda-mura. Ooe (15) N. Fwfimaki 970437 (2)24 30 }gll, Kamo C. Kami-takayanagi (12) 71 Sugarvara & T, Kuhara 970433 (2)24 31a NII. Kamo C. Kootsu I (8) ll Sugarvara & T. Kuhara 970428 (2)24 32 NII. Kamo C. Kootsu II (10) 71 Sugaivara & T. Kuhara 970426 (3)24 33 NII, Kamo C. IwanoI(5) T Sugavvara & Z Kuhara 970434 (1)24 34 Nll. Kamo C. Iwano II (12) 71 Sugawara & T. Kuhara 970427 (2)24 35 NII, Gosen C. Sakihana-onsen (15) 71 Sugawara & N, Fng'imaki 970325 (2)24 36 NII. Kanose-machi, Mizusawa (10) N. "{iimaki 970341 (2)24 37 NII. Kanose-rnachi, Fudotaki (11) T. Sugawara & N, Fwfimaki 970308 (2)24 394041 NII, Kamikawp-mura. Semigataira I (10) N. Fay'imaki 97042,1 (2)24 NII. Kamikawa-rnura, Semigataira II (7) N. Rijimaki 97VngO (2)24 Nll. Kamikawa-mura. Muroya (12) N. Fojimaki 971)422 (1)24 4244 NII. Karnikawa-mura, Kuratanisawa (10) N, Fojimaki 9605os, 970423 (2)24 FUK. Tadami-maehi. Gamo (10) T. Sugaveara & 71 Kuhara 9705os (2)24 4546 FUK, Kalleyama-machi, Oonabematusawa (15) N. Fojimaki 960504, 97V501 (2)24 NII. Mikawa-mura. Suwa-toge (10) N. ILtiimaki 960501 (2)24 47 NII. Sasakami-mura. Uodomenotaki (15) 11 Sugarvara & IV. Fng'imaki 9512(12, (2) , 9605a2, 9ro328 48 Nll, Kurokawa-mura, Kuromata I (24) Z Sugawara & N. Fng'imaki 960505, 24 (2) 970se3 49 NII, Kurokawa-mura, Kuromata II (8) T, Sugawara & N. Fwfimaki 97os39 24 (2)24 51 NII, -mura. Kanemata II (8) T. Sugawara & X Kuhara 970413 (4)24 52 NII. Sekikawa-rnura.･Ooishi (12) ll Sugarvara & IV. Fay'imaki 970veO (2)24 50 NII, Sekikawa-mura. Kanemata I (9) 71 Sugawara & N. F4iimaki 970330 (1)

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TABLE1. Continued.

Somatic chromosome No, Population Locality (Sample size)i}Voucher specimen number (Sample size)2}

53 Nll, Sekikawa-rrnma. Kami-kaMraguchi (10) T. S"gawara & N, Fay'itnaki 970314 24 (2)24 54 NII. Sekikawa-mura, Katsura (5) T, S"gawara & N. Fay'imaki 970335 (2)24 56 Nll, Sekikawa-rrrura, Takarios'u-ansen (12) T, S"gauara & N. Fwfimaki (2) 951204 970203, 970317 57 NII. Sekikawa-mura. Maese (8) T, Sugawara & T, Kuhara 970432 24 (2)24 58 Nll, Sekikawa-mura, Kanamar" I (10) T. Sugawara & N. Fng'imaki (3) 951203, 970337 59 NII. Sekikawa-mura. Kanamaru U (15) T. Sugawara & N. Fng'imaki 24 (2) 960403, 970332 60 YAM. Oguni-machi. Shimo-shinden (5) T, Sugawara & T, Kukara 970435 24 (2)24 61 YAM, Oguni-machi. Shinmyosan (20) T, Sugawara, N. Flofimaki & (2) T. Kuhara 960402, 970416 62b YAM. Oguni-machi. Ecchuzato I (3) T. Sugawara, IV. Fwfimaki & T. 24 (3) Kuhara 970409 63 YAM. Oguni-machi. Ecchuzato II (3) T, Sugawara, N. FLij'imaki & T. 24 (2) Kuhara 970410

TOY: Toyama Pref., NII: Niigata Pref., FUK: Fukushima Pref,, YAM: Yamagata Pref., AKI: Akita Pref. i)Number of individuals exarnined for analysis of morphelogical characters. 2)Number of individuals examined for karyotype analysis.

From the population samples the following characters were measured (Fig. 1): calyx tube length and width, diameter'ng,eksgalp,2,n.s･r.nd.,n,u,m,,gff of calyx tube entrance, g?la,I･,p,r.oiu,b,eB2pc,e,i:iniggh6Ae?,g,th,o,f,:,p,t,hgG?,o.f,g the number of longitudinal ridges on the inner surface of-the ealyx tube was examined. These features have been used as key characters in past taxonomic treatments (Maekawa, 1933,1988; Sugawara, 1996), or were newly discovered from my preliminary investigations to have possible taxonomic value.

Si(iig-･

FIG. 1. Measurernents of fiowers and leaves. a. Calyx tube length, b. Calyx tube width. Stylar protuberance length. d. Number ef trichomes per 10 mm2 on abaxial surface of a leaf.c.

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Karyological investigations were made from plants transplanted into the botanical garden of Shinshu University. The methods for observation of metaphase chromosomes are fully described in a previous paper (Sugawara and Ogisu, 1986).

Results

Chromosome number Four different ehromosome numbers (2n=24, 26, 36 and 48) have been reported for Japanese species of Asarum (Ono, 1960; Sugawara, 1981, 1991). Among these numbers the number 2n= 24 is the most common and 2n==48 is known only from Asarum megacalyx. These two numbers have been regarded as representing diploid and tetraploid states (Ono, 1960; Sugawara, 1991). In this study 2n=24 and 2n=48 were also observed (Fig. 2). The chromosome numbers observed in each population are shown in Table 1. Based on chromosome number, the 66 populations were divided into two groups: diploid populations, including numbers 1-8, 16-24, 26-31a, 32-37, 39-42, 44-54, 56-61, 62b, and 63 and tetraploid populations, including numbers 9-15, 25, 31b, 38, 43, 55,

.- '･iiek,1,uieg 'ts'･/,ag'gs･,"I' , kfif1. ,#ee, $m',%l'i'aglll'g\ eces･Lt,/tt,ll,,legag"" ililll･ /;}ft/ k/li,v :,lt, ,, wagiua ffii:1'it:tge me,tek

/t /t -tw1111',lj11 'ts'1'tman /Ml,//,' k" lliiXl i'iag:i･!ttl, ･ i"tt･k,1/･.'.'giiiij#,i,Xiua'me es,:/'tll;/tvar,la'/,eess- FIG, 2, Somatic metaphase chromosomes. A: Asarum ikegami'i var. ikegamii (2n = 24, fTom population 35), B: A. ikegamii var. fojimakii (2n=24, from population 57). C: A. yoshikawae (2n=24, from population 4). Arrows indicate four longer submetacentric chromosomes. D: A. megacalyx (2n=48. ftom population 15). Scale bar represellts 10 "m.

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62a, and 64-66. Chromosome numbers were usually consistent within each population. However, two chromosome numbers, 2n=24 and 2n=48, were found within two populations, numbers 31 and 62. Plants with different chromosome numbers grew side by side in the two populations, but I did not find hybrids (2n=36) among these plants. Furthermore, they differ from each other in floral morphology and in hairiness of the abaxial surface of the leaf blade, as mentioned below. Plants with different chromosome numbers were therefore suspected as belonging to different taxa.

Ka,lyotype In the diploids (2n=24) two different karyotypes were distinguished and are referred to as type I and type II (Fig. 3), In the type I karyotypes the two shorter chromosomes have centromeres in the subterminal region and possess satellites on the short arms (Fig. 3A; see also Fig. 2A, B). The other chromosomes have centromeres in the median region. This type of metaphase karyotype was found in 44 populations: numbers 16-24, 26-37, 39-42, 44-54, 56-61, 62b, and 63. In the type II karyotypes the four longer chromosomes have centromeres in the submedian region at metaphase (Fig. 3B; see also Fig. 2C). In this type the two shorter chromosomes with centromeres in the subterminal region were also found, as in type I. The other chromosomes were metacentric. Type II karyotypes were found in populations 1 through 8. In the tetraploids (2n=48) the four short chromosomes have centromeres in the subterminal region and satellites on the short arms. The other chromosomes have centromeres in the median region (Fig. 2D). The tetraploid appears to be a multiple of the type I diploid, because the karyotype is similar to that of the type I diploid in chromosomal constltutlon.

A

B li

FIe, 3. Idiograms showing haploid set of metaphase chromosomes. A: TypeIin Asarum ikegamii var. ikegamii. B: Type II in A. yoshikawae.

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(A)Diameter (B) of calyx-tube entranee (mm) Frequency(%)

2 4 6 8 10 12 14 16 O as 5e 75 leO

1234567s91011121314IS1617IS1920212223u252627ng293031a31b323334353637383P40414243"454647qe4gsoSlS2S354S5S657S859606162a62bfi3M6566 - . zemee1910.1516.2122. - -.

- -. . . - - . ･ . ------+ . -- -- " - :o'3.a..=Aopt .- :o.---di=Aopt " ･ - . - . - - . . ' - . - -- - - ' . ..

- - . - . " - - - . ･-

. - p t + - - - -

2 4 6 8 10 12 14 160 25 SO 7S 100

FTG. 4, Inter-pupulational variation in diameter (A) of calyx tube entrance and number of longitudinal ridges (B) within calyx tube in 66 populations. Dark box shows range between average ptus-minus standard deviation, Ends of bars represent mipimum and maximum values within a population.

Calyx tube entrance and reticulation ridges on inner suijbce ofa calyx tube Fig. 4A, variation in diameter of the calyx tube entrance in the 66 populations examined, shows that the calyx tube entrance varies considerably in diameter within and among populations. The entrance is conspicuously narrower in the eight type II diploid populations (nos. 1-8). In these eight populations the calyx tube entrance is consistently less than 4 mm in diameter. In other populations it is more than 4 mm in diameter. The reticulation ridges on the inner surface of the calyx tube have been usefu1 taxonomic characters (Sugawara, 1992, 1996). To compare the reticulation ridges, attention was paid to the number of longitudinal

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za5

(A) i

13 i i i i iLi.

21 i L -i i ii

iii i -ii - i. is . .i 1 19 t'i iti is t. :" -s i iJL "'Jt- Lii ` t E"g･VS . it'iiiL . -" " ii. -e . i . ii -- iSB6$ - '･ i. -Afi .

A 13811 ,･ A ge l,:lj3';,;l･ ' .:dA# '!'i es .': l.nAt:" thn.

e ,di,kglig-*' bAft6fi a 7 th

fi 4 se10121416 le

asev'snoess

Calyi-tubelength(mm)

/

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ridges extending from the base to the apex of the calyx tube. Frequency distribution of different numbers of longitudinal ridges in each population is shown in Fig. 4B. Longitudinal ridges are more numerous in the ejght 'to type II diploid populations (nos. 1-8), where they range from 16 24. In other populations the number of longitudinal ridges ranges mostly from 9 to 12.

Length and width of calyx tube, anther length and stylar protuberance length Fig. 5 is scatter diagrams of length and width of calyx tubes examined in the 16 tetraploid and 44 type I diploid populations. The eight type II diploid populations (nos. 1-8) are excluded because they differ in the diameter of the calyx tube entrance, showing clearly that tetraploid individuals are distinguishable from type I diploids. Separation is more apparent if a mean value for each population is adopted, as shown in Fig. 5B. Fig. 5B also shows that the type I diploid populations are bicentric. Eleven populations (nos. 50, 53-54, 56-61, 62b, 63), tentativeiy named the･ Arakawa populations because of their occurrence along the Arakawa River, deviate from the other 33 populations (nos. 16-24, 26-31a, 32-37, 39-42, 44-49, and 51-52, tentatively named the Yukiguni populations). Fig. 6, a scatter diagram combining the anther length of the inner stamens and length of the stylar protuberance in the 16 tetraploid and 44 type I diploid populations, shows that the tetraploid populations are separated from the diPloid populations, while the Arakawa and Yukiguni populations fall within the same range of variation.

Hairiness on the abauial sur:face of a leof blade The abaxial surface of the leaves is rough in tetraploids and smooth in diploids. Fig.7 shows the number of trichornes counted within a 10mm square area (see Fig. 1). Although the number of trichomes on the abaxia] surface of the leaf blade varies continuously, five classes were tentatively recognized. Based on these classes, frequency of distribution of plants in the four population groups, which are characterized by ploidy level,,karyotype and calyx tube size (tetraploids, Arakawa, Yukiguni, and type II diploid populations).are categorized (Fig. 7). The abaxial surface of the Ieaf tends to be more densely hairy in tetraploids and sparsely hairy or glabrous in the diploids.

OTIfice ring development and position of the stylar protuberance within the calyx tube Fig. 8 is a scatter diagram of the length of the anthers of the inner

t- FIG. 5. Scatter diagrams showing relationship between ca]yx tube length and calyx tube width in 58 populations, A, Tetrap]oid populations (=A, megacalyx)=closed triangle, type I diploid populations along Arakawa River (==itl. ikegamii var. juiimakii)==(closed circle), and other type I diploid populations (=A. ikegamii var, ikegamii)==(open triangle), B, Mean values of the tetraploid populations (closed triangle), type I diploid populations along the Arakawa River (closed circle), and other type-I diploid populations (open triangle). Scopes of standard deviation obtained from popuiation sarnples is indicated in diagram.

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5.0

A 4.oEEvsttg

,,,Tues:

2.0E g.,

g 10ua

o.o 1.o ZO 3.0 4.0 s.O 6.o Anther length of inner stamen (mm)

of inner stamen apd stylar FIG. 6. Scatter diagram showing reLationship betweell anther length ?",os"Yei:sfae,ae:g`,h.l':,,gE,p:p,."seti:;Lesti,:xtraRt･2ge=p'.ia.tl･22E,tT-,,"･",Z."g,"8･:･,.lyi,',･]ee`,:,d.,trigi,glg: Scope of standard other type I diploid populations (=A, ikegamti var. ikegamii)==open circle. deviations obtained from population samples indicated in diagi'am,

100 tw o

ge 1-10 7SAs pt 11.30

M 3i-7o saeS.'mo. g - 71.

25

gA c

FI6. 7. Frequency of nurnber of trichomes per 10mm2 on abaxial surface of leaf. A. Samples (N==136) from 16 tetraploid populations (=-=-A. megacalyx). B. Samples (N==:143) from 11 typeI diploid populations along Arakawa River (=!A. ikegamii var. fojimakii). C. Samples (N==458) from other 33 type I diploid populations (=A. ikegamii var. ike.aamii). D. Samples (N=56) from eight type Il diploid populations (=A, yoshikawae).

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N"sg

f' 5 : /k 7tts :t e･

O 3 4 smm

Anther length of inner stamen

FIG, 8. Scatter diagram showing relationship between anther length of inner stamen and calyx tube width minus diarneter of calyx tube entrance!2 in 44 type I diploid populations, C]osed circle=Arakawa populations (=A. ikegamii var. faiimakii) and open circle==other type I populations (=tA. ikegamii var. ikegamii). Scopes of standard deviation obtained from population sumples indicated in diagram,

stamens and the extent of orfice ring development (=caiyx tube width minus diameter of calyx tube entrance/2) in the 44 type I diploid populations. It is clear that the 11 Arakawa populations (nos. 50, 53-54, 56-61, 62b, 63) deviate from the 33 Yukiguni populations (nos. 16-24,26-31a, 32-37, 39-42, 44-49, and 51-52) by having a more developed orfice ring. The position of the six stylar protuberances within the calyx tube is also noteworthy. The stylar protuberances are always shorter than the calyx tube and do not extrude from the calyx tube entrance (Fig, 9B) in the Arakawa populations, while they are nearly as long as the calyx tube and occasionally exserted beyond the calyx tube entrance in the Yukiguni populations (Fig. 9C, D).

Discussion

The study was initiated to determine the taxonomic disposition of unusual plants of Asarum and plants referred to as Ht]terotropa yoshikawai, nom. nud. (Ono, 1960; Maekawa, 1964, 1968) occurring in Niigata Prefecture and adjacent area, and to clearly delimit A. megacalyx and A. ikegamii In spite of their overall similarities the results

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'

X

FiG. 9. Representative flowers of four taxa of Asar"m. A, Asarum megacalyx (frorn population 10). B. A. ikegamii var, fajimakii (from population 59), C, D. A, ikegamii var. ikegamii (C, from population 4t; D, ftom poputation 48). E, A, yoshikawae (fiom population 6).

TABLE 2, Major differences arnong Asarum yoshikawae, A. ikegamii var, ikegamii, A. ikegamii var. fojimakii and A, megacalyx.

A. ikegamii Character A. yoshikawae A. megacalyx var, ikegamiivar, faiimakii

Leaf Glabrous and Usually glabreus Usually glabrousHairy and usually lustrous and lustrous and lu$trous lusterless Flower Shape of calyx-tube Urceolate- Broadly tubular Tubular-globose Tubular-g[obose campanulate

Size of calyx-tube 7-11 mm long, 4-9 mm long, 7-'14 mm long, 11-19 mm long, 8u12 mm wide 6-14 rnm wide 10-18 mm wide 14-24 mm wide

Numbev of longitudinal ridgesUsually 16-24 Usually 9-15 Usually 9-15 Usually 9-15

Diameter of calyx- 1-4 mm 4-10 mm 4-11 mm 7-15 mrn tube entrance

Stylar-protuberance Shorter than Nearly as long ShoTter than Shorter Than the calyx-tube as the calyx-tube the calyx-tube the calyx-tubc

=-' Chremosome number 2n =24Type-IIToyama 2n==24Type-INiigata2n=24Type-INiigata2n 24Typerl2n==48Niigata,Nagane, Karyotype Distribution and Niigata and aid Prefs. Fukushima Prefs, Yamagata Prefs. Fukushima, Yamagata, Akita & Gunma ?refs.

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June 1998 SUGAWARA: Taxonomy of Asamm 13

reconfirmed the differences between those two speeies and highlighted the distinctness of a new species, Asarum yoshikawae, in karyological and morphological features. The unusual plants occurring along the Arakawa River represent a new variety of A. ikegamii, variety fojimakii. Major differences among these four taxa are summaried in Table 2; examples of typical flowers from each of them are shown in Fig. 9. Among the three closely related species, differences between AsaTum yoshikawae and A. megacalyx are most obvious. They differ not only in chromosome number but alse in karyotype: A. yoshikawae is diploid (2n=24) and characterized by having a type II karyotype (four longer submetacentric chromosomes in metaphase chromosomes), while A. megacalyx is tetraploid <2n==48), as reported by Ono (1960), and Iacks the long submetacentric chromosomes. Asarum yoshikawae is also characterized by its urceolate-campanulate calyx tube, a well-developed orfice ring, and complicated reticulation ridges on the inner surface of the calyx tube. Asarum ikegamii is also diploid, and is characterized by its type I karyotype and a smaller, tubular calyx tube. Throughout the range of the species (Fig. 10), the flowers, particularly the calyx tube and anthers, vary considerably in size within and among populations. Morphological examination shows that A. ikegamii consists of two infraspecific taxa, var. fojimakii and var. ikegamii, which correspond with the Arakawa and Yukiguni population groups (Fig. 10), respectively. In var. fojimakii the calyx tube is larger (Fig. 5), and the annulus of the calyx tube is more

i AsO

A.

- A. ef, - A

v

T

FfG. 10. Collection sites and distribution of the iour taxa.

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14 Acta Phytotax. Geobot. Vol, 49

developed, forming an obvious orfice ring at the calyx tube entrance (Fig. 8). Furthermore, the stylar protuberances in var. fojimakii are always shorter tlian the calyx tube, and are not exserted from the calyx tube entrance (Fig. 9). In earlier reports (Maekawa, 1964, 1968; Hasegawa and Tomotori, 1981), the tetraploid species Asarum megacalyx was considered to be closely related to A. yoshikawae. The karyotypes of the two specjes, however, differ from each other. In addition, reticulation on the inner surface of the calyx tube and the development of the orfice ring also einphasize the difference between the two species, In contrast, A. ikegamii and A. megacalyx closely resemble each other in sharing the type I karyotype, despite their differences in chromosome number. The two species are also similar in having a tubular-globose calyx tube and in the simple reticulation ridges on the inner surface of the calyx tube. These karyological and morphological similarities suggest that A. megacalyx is closely related to A. ikegamii, particularly to var. fojimakii.

Taxonomy

Asarum yoshikawae T. Sugaw,, sp. nov.

Heterotropa yoshikawai F. Maek. ex Ono, in J. Fac. Sci, Univ. Tokyo, seet. III, 7: 47g (1960), nom, nud.; Maekawa in Ishii and Inoue, Encycl. Hort, 2: 184 (1968), nom. nud,; Satake & Momiyama in Satake et al., Wild Row. Jap. Herb. 2: 109 (1982), nom. nud. Haec species Asaro ikegamii valde affini$ est, sed tubo calyce urceolato-campanu]ato, reticulatione complexo, ostio tubo parvo distinguitur. 7Mpe. Japan, , Niigata Pref., Joetsu City, Nakanomata, 140m, T, Sugawara 970425 (holotype: MAK; Isotypes: SHiN, TI).

Perennial with somewhat Iong rhizomes. Leaves broadly ovate to triangular ovate, 7-13cm long, 5-9cm wide, apex slightly acute, base cordate; upper surface usually light green, lustrous, glabrous, without variegation; lower surface pale green, glabrous; petiole dark brown or green, glabrous, 9-18cm long. Flowers dark green, solitary, axi11ary, March to April, decumbent on ground; pedicel 1-4 (-5) cm long; calyx tube urceolate to campanulate, 7-11 mm long, 8-12 mm wide, throat not constricted, inner surface complicated!y tessellated with perpendicular longitudinal and transverse ridges; longitudinal ridges most]y 16-24; limb 3-lobed; calyx tube entrance less than 4mm in diam.; orfice ring prominently developed; calyx lobe spreading obliquely, uiangulate to ovate, 8-14mrn long, 8-14rnm wide, smooth above, glabrous beneath; stamens 12 in two whorls, 2-3.5mm long, filamepts very short, anthers extrorse, ca. 1.5-3mm long, apex of connectives rounded to truncate; ovary superior, 6-locular; styles 6, free, with horn-like stylar protuberance at apex; stylar protuberances shorter than calyx tube; stigma elliptical, extrorse; ovules 8-1.2 in each locule. Chromosome number 2n=24, karyotype symmetrical. Japanesename. Kurohimekan-aoi. Distribution. Eastern Toyama Prefecture and western Niigata

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June1998 SUGAWARA: TaxQnomy of Asarum 15

Prefecture.

Asarum ikegamii (F. Maek. ex Y. Maek.) T. Sugaw., comb. nov. Heterotrqpa ikegamii F, Maek. ex Y. Maek,, in J. Jap, Bot. 63: 36 (1988), 7),pe. Japan, Honshu, Niigata Pref., Sumon-mura, May 22, 1983, Z Maekawa (holotype: ").

Asarum ikegamii var. ikegamli Flowers broadly tubular, 4-9mm long, 6-14mm wide, throat not constricted; calyx tube entrance 4-10mm in diam.; orfice ring not prominent; anthers extrorse, 1.5-3 mm long; stylar protuberances nearly as long as calyx tube, or rarely exserted beyond calyx tube. Japanesename. Yukigunikan-aoi Distribution. Central to northern Niigata Prefecture and western Fukushima Prefecture.

Asarum ikegamii var. fiijimakii T. Sugaw., var. nov.

Ab var. ikegamii tubo calyce majore et protuberantia stylo quarn tubo calyce semper brevi differt, 71ype, japan, Honshu, Niigata Pref., Sekikawa-mura, Kanarnaru, 160m, T. Sugawara and IV. ftijimaki 97a337 (holotype: MAK; Isotypes: SHIN, TI).

Lamina broadly ovate to ovate, 6-11cm long, 5-9cm wide, apex slightly acute, base cordate; upper surface lustrous, glabrous or sparsely hairy, variegated or not, veinlets slightly impressed. Flowers dark green to dark purple, March to April; calyx tube tubular to globose, 7-14 mm Iong, 10-17 mm wide, throat not constricted, tessellated with longitudinal

and transverse ridges on inner surface, longitudinal ridges usually 10 to 15; calyx tube entrance 4-11 mm in diam,; orfice ring somewhat developed; anthers 1.8-3.8mm long; stylar protuberance shorter than calyx tube. Chromosome number 2n=24, karyotype highly symmetrical. Jcrpanesename. Arakawakan-aoi Distribution. Northern Niigata Prefecture and southwestern Yamagata Prefecture. This variety cliffers from var. ikegamii in having a larger calyx tube and sty]ar protuberances always shorter than the calyx tube.

I am grateful to Mr. N, Fujimaki for providing valuable material and for his help in the field stucly and to Messrs, Y. Horii and T. Kuhara for providing material. I am also indebted to Dr. J, Murata of Tokyo Metropolitan University for critically reading the manuscnpt.

References

Hasegawa, Y. and H. Tomitori. 1981. Distribution of some plants occurring on Niigata Tertiary Basin, Niigata Prefecutre, Japan, J. Phytogeogr. & Taxon, 29: 60-66 (In Japanese), Hatusima, S. and E. Yamahata. 1988. Il!egitimately published taxa of Asarum from Japan. J. Phytogeogr. & Taxon. 36: 1-8.

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16 Acta Phytotax． Geobot ． Vo1 ，49

正shizawa S．／996， Distribution Maps in Comparison with The 正ndicator Plant CameUia ， ， aponica Thunb ． subsp ． rusticana Honda Kitamura ． Jap． Sci． Soc、 Press Tokyo ln ／ （ ） ， （ Japanese）、 一 − − Maekawa ， F ．1933． Japanese Asaraceae （1） （V 【1）． 」． Jap． Bot ，9 ： 39 49，96 103， − − − − 174 181， 241 246 ， 281 285 ， 364 370 ， （ln Japanese）． − ．1934Japanese Asaraceae （VIII）． 」． Jap． Bot ．iO： 358 362 （ln Japanese）． ．1964．Geohistory and plant speciatiGn ． Shizenkagaku to Hakubutsukan 31 ： − 2 15 （ln Japanese） 一 一一 ．1968．H 漉 厂o か 〇 ．ノit Inoue Y 、 et ai ． eds ． Encyclopedia of Horticulture 2 ： 四 ， （ ）， − − 1024 1 29 ．Seibundo shinkosha ， Tokyo （ln Japanese）， new species of 餾 ro μ Maekawa ， Y ．1988．A H 尠 ρ （Aristolochiaceae）from HQnshu ， Japan ． − 」．Jap． Bot ．63： 33 37 （ln Japanese with Engulish s田 皿 mary ）． Ohwi J、1975． Flora of Japan ． New ed ，revised and enlarged ． Shibundo Tokyo ． ， ， ， ． on and related with special reference to their Ono ， M 196G Studies Heterotropa its genera ． − karyo皿 orphol ．ogy and phylogeny． 亅． Fac． Sci． Univ ． Tokyo III 7 ： 473 499 ． Satake Y ． and Y ． Momiyama 。1982． Airistelochiaceae． In Satake Y ．θ‘ at ． eds ． ， ， （ ），Wild − Flowers of Japan II： 102 109． Heibonsha Tokyo ln Japanese ． ， （ ） Sugawara， T ．1981． Taxonomic studies of Asarum sensu iato I． Karyotype and C −banding pattern in Asarum s ． str．，．4siasarum and Heterotropa． Bot． Mag ．（Tokyo ）94： 225− 238，

．199L The 、4sctrum： characteristics classificat ｛on and relationsh 孟 ． Proc ． genus ， ， ps − Jap． Soc． P1． Tax ．8： 83 90 （ln Japanese with English summary ）． ，1992 ． Ataxonomic study of Heterotroρa η ψρo 廨 c α and H ， savatieri ssp ． pseudosavatieri （Aristolochiaceae）in the Shima Peninsula． Acta Phytotax． Geobot ． − 43： 15 26，

． 1996．A ．new species of Asarum Aristolochiaceaefrom Goto Islands （ ） ， Japan， − Acta Phytotax． Geobot．47： 135 141， and M ． Ogisu． 1986． Karyotype ana ユysis of five species of Asarum Aristolochiaceae ． ． ． ． ； ユ − ． （ ）inSichuan， China J Jap Bot 61 04 111 Yuhki Y ．1992，New ， Flor乱 of ￥amagata ． Member of Flora Ya 皿 agata ， Yamagata （ln Japanese）．

摘 要

菅原 敬 ：新 潟県 と その 隣 県 に分布 する カ ン ア オ イ 属 植物 ，特 に コ シノ カ ン ア オイ とそ の 近 縁種 に 関 す る分 類学 的 研究 1．996 の で カ ン ア 年新 潟県 北 部 荒 川流 域 奇妙 な オ イ 属 植 物 が 確認 され た 。 こ の 植 物 は， 同 地 域 周辺 か ら従来 報告 され て い た コ シ ノ カ ン ア オ イ （Asarurn megaca ！yx F ． Maek ．），あ る い は ユ キ グ ニ カ ン ア オ イ （A ， ikegamii［F ． Maek ． ex Y ， Maek ．］T ． Sugaw ．）に よ く似 る が ，花 一 の 形 態 は そ れ ら の 中 型 の よ に み る 一 の 間 う え 。 方 ， 新 潟県西部 か ら富 山 県 東 部 地 域 に は未 記

ク ロ ヒ メ カ ン ア オ Eleterotroa い 載種 イ （ ρ yoshikaveainom ．nud ．）が 知 られ て た 。 こ の 植 物 も コ シ ノ カ ン ア オ に い イ 近縁 と見 な さ れ て きた が ， まだ そ の 実 体 は 充分 に 解 明 され て い な い 。 そ こ で こ れ ら問題 の 植物 の 分 類 学 的位 置 づ け，な らび に既存 の 2 種 と の 関連 を明 らか にす る

た め 花 の 形 態 な ら び に染 色 体 か ら の 比 を進 め た の ロ ヒ メ カ ン ， 較 研究 。 そ 結 果 ， 未 記 載種 ク

ア オ イ は 立 と み な し る こ とが し た の で 独 種 う 判明 ， Asarum yoshikawae T．Sugaw ．の 学名 で

正 な を た ま た の の ン ユ ニ 式 記 載 行 っ ， 荒 川流 域 問 題 カ ア オ イ属植 物 は キ グ カ ン ア オ イ の 新 変

と づ け ら れ ア ラ カ ワ カ ン ア オ イ Aikegamii var 種 位 置 ， （ ．fOjimakiiT ．Sugaw ．）と して 記 載 ロ メ ン し た 。 ク ヒ カ ア オ イ は萼筒 が 上 方 に狭 ま っ た 筒形 で ，萼 筒 口 が 径 4mm 以 下 と著 し く

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June 1998 SUGAWARA ： Taxonomy of Asarum 17

狭 く，萼筒内壁 の 襞は 著 し く複雑化 す る 。 また 中期 染色体 で も 4 本 の 次 中部型染 色体 を含 む 一 固 有 の 核 型 を も つ 特 異 な 種 で あ る 。 方新 変種 の ア ラ カ ワ カ ン ア オ イ は狭義 の ユ キ グ ニ カ ン

var に べ て よ ［コ よ て だ つ ま た ア オ イ （ ，ikegamii） 比 萼筒 が り大 き く， 環 も り発達 し 目 。 ，花柱

ユ ニ ン の に で こ と は に 附属 突起 は キ グ カ ア オ イ の よ うに 萼筒 口 高 さ ま 達 す る な く， 常 萼 筒 内

い で にお さ ま っ て る 。 こ の 新変 種 は 荒川流域 に 沿 っ て 新潟県 関川村 か ら山形 県小 国町付近 ま

分布 す る 。 − − − （〒 390 8621 松 本 市旭 3 1 1 信州 大学 理 学 部 生物 科学教室）

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