Taxonomicstudiesofbistorta
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4favJ直-一物取沿研けト内九、知別雑し誌∞ 周，，7 ρ ウ』、、‘.，，， Originals Originals Taxonomic Studies of Bistorta (Polygonaceae) in the Himalayas and Adjacent Regions (2). - Bistorta amplexicaulis (D.Don) Greene and Its Allies ， with Special Reference Reference to the Ochreae and Leaf Sheathes of Cauline Leaves K 吋i YONEKURAa and Hiroyoshi OHASHl b aThe aThe M t. Hakkoda Botanical Laboratory ，Graduate School of Science ， Tohoku Tohoku University ，Aomori ，030 ・0111 JAPAN; bBotanical bBotanical Garden ，Graduate School of Science ，Tohoku University ，Sendai ， 980-0862 JAPAN (Received (Received on Septernber 25 ， 2001) Bistorta Bistorta amplexicaulis (D.Don) Greene and its allies are taxonomically revised. Well-developed Well-developed leaf sheathes of cauline leaves are considered as an apomorphic charac- ter ter in Bistorta ， and B. amplexicaulis lacking such leaf sheathes is assumed as a primitive species species in the genus. A new variety ，B. αmplexicaulis subsp.α mplexicaulis v紅. dhorpatanensis dhorpatanensis Yone k. & H.Ohashi ， is described from cenral Nepa l. Bistorta amplexicaulis amplexicaulis subsp. sinensis (Forbes & Hems l.) Sojak is regarded as a species distinct from B. amplexicaulis and a new name ， B. henryi Yonek. & H.Ohashi ，is proposed for it. Bistorta Bistorta sinomontana (Sam.) 恥1iyam. is reduced to a subspecies of B. amplexic αulis and a new combination ， B. amplexicaulis subsp. sinomontana (Sam.) Yone k. & H.Ohashi ，is proposed. proposed. Key words: Bistort α， amplexicaulis ，Bistorta hemyi ，leaf sheath ，ochrea ， taxonomy. Bistorta Bistorta amplexicaulis (D.Don) Greene is less attentions have been paid to their taxo- a rather common species in the moist tem 圃 nomic value. During our revisional work ，we perate perate to alpine regions of the Himalayas to found that ratio of the leaf sheath to the central central China. This species is characterized ochrea in the cauline leaf is taxonomically by elongated ，branched thick woody rhi- significant in Bistorta (Y onekura and Ohashi zomes and ovate cordate leaves ， but is vari- 1999 ，2001). 乱10st species of Bistorta have able able in its general habits ，inflorescence sizes ， cauline leaves with well developed tubular and colours and sizes of flowers. Due to its leaf sheathes much longer than their diame- variability variability this species has been divided into ter and less developed ochreae (Fig. 1) ， several several infraspecific taxa or even into several while some species including B. αmplexi- distinct distinct species (Meisner 1826 ， Steward caulis have poorly developed leaf sheathes 1930 ，Munshi and Jabeid 1986). hardly forming complete tubes and long The ochrea is an organ characteristic to ochreae even in the uppermost cauline the the subfamily Polygonoideae of Polygon- leaves (Fig. 2). These two pattems are dis- aceae aceae and regarded as useful in classification tributed in Bistorta and related genera ，i. e. ， of of some groups (Stew 訂 d 1930 ，Park 1988) ， Aconogonon ， Koenigia ， Persicaria and but but in Bistorta all species have tubular F agopyrum belonging to the tribe Persic 闇 glabrous glabrous ochreae similar in shape and hence arieae (Haraldson 1978 ，Ronse Decraene and -61- 62 植物研究雑誌第77 巻第2号 平成14 年4月 b 3 2 a b 4 5 Figs. Figs. 1-5. Leaf sheathes and ochreae of cauline leaves in Bistorta and its allied genera. Dotted Dotted lines indicate borders between leaf sheathes (l ower part) and ochreae (upper p制); broken lines indicate stem nodes. For convenience ， nerves and hairs on ochreae and and leaf sheathes 紅 e omitted and cauline leaves 紅 e represented by their costae. 1. B. major var. japonica (Ohashi et al. 28175 ， TUS). 2. Bistorta amplexic αulis subsp. sinomontana sinomontana (Yu 15380 ， A). 3. Persicaria lapathifolia (Sato s. n. ，TUSG). 4. Aconogonon weyrichii (Naito 7288 ，TUSG). 5. Fagopyrum dibotrys (Yamanaka s. n. ， TUSG). a: Lower leaves. b: Upper leaves. Scale bar = 2 cm. Akeroyd 1988) as shown in Table 1. Genera that the well developed leaf sheath of the related related to Bistorta have poorly developed cauline leaf is an apomorphic character in leaf leaf sheathes hardly forming complete tubes Bistorta and B. amplexicaulis is situated on and and developed ochreae (Figs. 3-5). In the primitive position in this genus. Bistorta Bistorta species with poorly developed leaf Although some infraspecific taxa of B. major sheathes sheathes have underground organs different Gray (= Polygonum bistorta L.) 紅 e some- fromm 卯rity of this genus ，i. e. ，much elon- what similar to B. amplexicaulis in general gated gated and branched rhizomes as in B. appe 紅 ance ， they are easily distinguishable amplexicaulis amplexicaulis or woody wiry pros 佐ate stems from the latter by their ochreae and leaf against against short thick unbranched tortuous sheathes of cauline leaves (Figs. 1 ，2). bistort") (“ bistort") rhizomes from which the generic In the Himalayas westwards from Bhutan name is derived. Genera related to Bistort α Bistorta amplexicaulis grows in wide range have have various shape of underground organs of habitats and elevations ， but keeps stable but but no species in these genera. have “bistort" features ，i. e. ， the ovate to elliptic leaves with rhizomes. rhizomes. Based on these facts we consider almost wingless petioles ，floral bracts pぽ tly Apri12002 Joumal of Japanese Botany Vo l. 77 No. 2 63 Table Table 1. Development of leaf sheathes and ochreae in the Bistorta species and its allied allied genera. Species with asterisk (*) have short unbranched thick tortuous rhizomes rhizomes common in Bistorta. In species above B. vivipara ochreae of upper cauline cauline leaves are much shorter than the leaf sheathes and often vestigial Leaf Leaf sheathes ill-developed; Leaf sheathes well-developed; ochreae ochreae well-developed Ochreae ill-developed Bistorta Bistorta bistortoides * B. B. co ゆ sa * B. B. coriacea * B. B. hayachinensis * B. B. macrophylla * B. B. major * B. B. plumosa * B. B. tenuicaulis B. B. vivipara * B. B. a!J が守 n B. B. burm αni たCα* B. B. diopetes * griffithii B. griffithii B. B. hayachinensis * B. B. longispicata * B. B. ludlowii * B. B. milletioides キ B. B. perpusilla * B. B. purpureonervosa * B. B. rubre * B. B. sherei * B. B. subscaposa * Bistorta Bistorta abukumensis B. B. amplexicaulis B. B. emodi B. B. S l{ がuω B. B. vacciniifolia Persicaria Persicaria Aconogonon Koenigia Koenigia Fagopyrum inserted inserted in the inflorescence rachis but not Nepal to westem Bhutan. Although altitudal completely completely surrounding it (Fig. 6) ， and her- distribution ranges of both groups are over- maphrodite maphrodite flowers with tepals obtuse or lapping as shown in Fig. 8，they 紅 e gener- rounded rounded at apex. Two groups 訂 e recognized ally isolated from each other and intermed 剛 based based on difference in the inflorescence ori- iates 紅 e very rarely found. entation; entation; a group with erect inflorescences The former group is very variable. The growing growing in the cool temperate zone ， and the commonest form has rather short inflores- other other group with pendulous inflorescences cences with deep red flowers 1-4 in each growing growing in the alpine zone from central node and occurs in Nepal and adjacent re- 64 植物研究雑誌第77 巻第2号 平成14 年4月 acute acute or subobtuse leaves and drooping inflorescences inflorescences with one flower in each node ， whose tepals are red ， broadly elliptic and rounded rounded at apex. All individuals of this group group from central and eastern Nepal west- wards wards to Manaslu Himal share such charac- ters ters and its varietal rank is acceptable. Noshiro Noshiro et al. 9760372 (TUS) from the upper Iswa Iswa Kh ola valley in eastern Nepal has white リレー cross section tepals with reddish veinlets ， but it is nothing ~.....y a more than a form. Hara (1975) pointed out papillae papillae on the lower surface of leaves as a ~b ② b diagnostic character of this variety ， but they are are also found in several specimens of var. 6 7 amplexicaulis (e. g. ， Suzuki et al. 9460098 (TUS) and Mikage et al. 9685283 (TUS)). Figs. Figs. 6- 7. Inflorescence rachis with bracts (a) and Several collections of Bistorta amplex- schimatic schimatic figures of their cross-section between icaulis from Dhorpatan region in south of 紅 TOWS (b). Dotted lines indicate connections be- Dhaulagiri Himal and Modi Kh ola Valley of tween tween bracts and rachis. For convenience ， Annapurna Annapurna Himal in central Nepal 紅 'e simi- bracteoles bracteoles and flowers 訂 'e omitted. 6. Bistorta amplexicaulis amplexicaulis subsp. amplexicaulis. 7. B. henryi lar to var. pendula in having drooping (= (= B. amplexicaulis subsp. sinensis). inflorescences ， but are different by their inflorescences inflorescences with usuallY two or three pink flowers flowers in each node and by their tepals nar- rower rower than var. pendula. Their localities are gions. gions. In the western Himalaya individuals separated from the distribution area of var. with with long inflorescences and white or pendula by Marsyandi valley as shown in pinkish pinkish smaller flowers are frequently found Fig. 8. According to the field observation by and and have been named Polygonum ambiguum the first author in Dhorpatan region ， they Meisn. Meisn. or P. oxyphyllum Meisn. On the other were growing in alpine grasslands and a司ja- hand ，plants with short thick inflorescences cent Betula - Sorbus forests more than 3490 with with red large flowers 紅 e known in the m at altitudes. Individuals of v紅 .α mplexi- higher higher elevations in Sikkim and eastern caulis were sometimes found together in Nepal Nepal and have been named Polygonum same places but only one individual was speciosum speciosum Meisn. These forms are ，however ， found intermediate between them. We con- connected connected with many intermediates and geo- sider the collections as a distinct variety and graphical graphical isolations among these forms are named it as v紅 . dhorpatanensis Y onek. & not not observed according to our field re- H.Ohashi. searches searches in Nepal and examinations of speci- Munshi and Jabeid (1986) recorded mens.