植物研究雑誌 J. J. Jpn. Bo t. 71: 71: 273-280 (1996) The Leaf Organization of Kummerowia (Leguminosae) Yu IOKAWA ，Tomoyuki NEMOTO and Hiroyoshi OHASHI Biological Biological Institute ，Graduate School of Science ， Tohoku University ，Sendai ，980-77 JAPAN (Received (Received on March 18 ， 1996) Leaves Leaves of Kummerowia have been described as palmate or as pinnate. In order to clarify leaf the organization ，leaves of Kummerowia were examined morphologically and anatomically. Mo 中hological observations observations revealed that rachis exists between the top of petiole and the pulvinus of terminalleaflet. The rachis differs differs from the pulvinus in having two ridges on the adaxial side and no wrinkle in surface. Though the rachis becomes becomes shorter in upper leaves ， it is clearly distinguished from the pulvinus by these extemal features. The leaf organization organization of Kummerowia is therefore regarded as being pinnately trifoliolate. Anatomical observations revealed revealed that the leaf of Kummerowia has a similar vascular system to that in the pinnately trifoliolate leaves of other other leguminous species. The leaf organization of Kummerowi αis identical with those of its allied genera Lespedeza Lespedeza and Campylotropis. The genus Kummerowia comprises two species ， Kummerowia has more closer relationship to K. K. striata (Thunb. ex Murray) Schindler and K. Lespedeza than to Cα mpylotropis. st 伊ulacea (Maxim.) Makino. These are naturally Leaves are trifoliolate in those three genera and distributed distributed in East Asia and have been introduced they have been usually described as pinnately widely widely in North America. This genus is included in trifoliolate in Lespedeza (Hutchinson 1964 ，Ohwi the the subtribe Lespedezinae of the tribe Desmodieae 1965 ， Isely 1990 ， Li and Chen 1995) and together together with allied genera Lespedeza and Campylotropis (Hutchinson 1964 ，Fu 1987 ， 1995). ampylotropis C ampylotropis (Ohashi et al. 1981). Taxonomic treat- On the other hand ，trifoliolate leaves of Kummerowia ments ments of these generahave been controversial (N emoto have been described as palmate (Watari 1934 ，Ohwi and and Ohashi 1988) ，and the relationships between them 1965 ， Hatusima 1975 ，Isely 1990) or as pinnate (Liu have have been discussed on basis the of the floral nectary 1955 ，YangandHuang 1995). AccordingtoOhashiet (Nemoto and Ohashi 1988) ， the inflorescence al. (1 981) ，leaves of the tribe Desmodieae are gener- (Akiyama and Ohba 1985 ，Nemoto and Ohashi 1990 ， ally pinnately trifoliolate. 1993 ，1996 ，Nemoto et al. 1995) and restr Ic tion frag- The pinnately trifoliolate leaf is distinguished from ment length polymorphisms of chloroplast DNA the palmately trifoliolate one by the presence of the (Nemoto et al. 1995). Akiyama and Ohba (1 985) rachis above the petiole (Hickey 197 9.). Because each regarded regarded Kummerowia as being distinct from other leaflet has the pulvinus at the base throughout the two genera based on the features of inflorescence ， Leguminosae (Dormer 1946) ，the petiole is connected whereas whereas Nemoto and Ohashi (1 988 ，1990 ，1993 ， by the rachis with the pulvinus of terminalleaflet in 1996) 1996) and Nemoto et al. (1 995) showed that the pinnately trifoliolate leaf ， while it is directly -273 ー 274 植物研究雑誌第71 巻第5 号 平成 8 年 10 月 connected connected with that in the palmately trifoliolate one. Observations Watari Watari (1934) anatomically studied the vascular M orphologic α lobservation A leaf of Kummerowia system system in the petioles and rachises of many legumi- comprises three leaflets. Each leaflet has a pulvinus at nous nous species and pointed out the difference in vascu- the base. We observed the rachis between the top of lar lar system between the pinnately trifoliolate leaf and petiole and the pulvinus ofterminalleaflet (Figs. 1，2， the the palmately trifoliolate one. He regarded K. striata 3). The pulvinus ofterminalleaflet attaches on the top as as having the vascular system in the palmately of the rachis ， while that of the lateralleaflet attaches trifoliolate trifoliolate leaf. directly to the top of petiole. The rachis is clearly In In this paper ， in order to clarify the leaf organiza- distinguished from the pulvinus by the following tion ，we examined leaves of Kummerowia morpho- differences: the rachis has two ridges running along logically logically and anatomically. the adaxial side ，slender outline and smooth surface ， while while the pulvinus has no ridges ， but swollen outline Materials Materials and Methods and wrinkled surface. Moreover ， the pulvinus falls Leaves Leaves of Kummerowia striata and K. stipulace α down with the terminalleaflet when plants shed their were examined. Typical palmately trifoliolate leaves leaflets ， but the rachis remains at the top of petiole. of of Trifolium repens L. were also examined for com- The rachis varies in length ，0.2-1 .4 mm long in K. parison. parison. For mo 叩hological observations ， herbarium striata and 0.1 -0 .8 mm long in K. stipulacea. Al- specimens specimens kept in TUS were investigated under a though it becomes shorter in upper leaves in both binocular binocular microscope. Moreover ，FAA-fixed leaves species (Figs. 3，5) ， the rachis is clearly distinguished collected collected in the fields (Table 1) were dehydrated in an from the pulvinus by those different features. ethyl ethyl alcohol series ，transferred to isoamyl acetate ， Leaves of Trifolium rψens ，which represent a dried dried in a critical point dryer ， placed on aluminum typical palmately trifoliolate leaf ， don't have the stubs ， coated with gold ，and observed by a Hitachi S- rachis and the three pulvini of leaflets are attached 4100 scanning electron microscope. For anatomical directly to the top of petiole (Fig. 4). Leaves of observations ，FAA-fixed materials were dehydrated Kummerowia are clearly different in structure from in in a t-butyl alcohol series ，embedded in paraffin and the palmately trifoliolate leaf. sectioned sectioned at a thickness of 10μm with a rotary Anatomical observation The rachis can be distin- microtome. microtome. Sections were stained with safranin and guished from the pulvinus of terminalleaflet by the fast fast green FCF and examined by a light microscope. shape of the transverse section in K. striata and K. Table Table 1. A list of fresh and F AA -fixed materials examined. Voucher specimens are are all kept in TUS Taxa Taxa Locality & Collector Kummel ・owia Japan ，Miyagi Pref. ，Sendai ， Y. Iokawa 5240. stipulacea stipulacea Japan ，Fukushima Pref. ，Hobara 司 machi ，y. Iokawa 5238. Japan ，Fukushima Pref. ，Yabuki-machi ， Y. Iokawa 5242. striata K. striata Japan ，Miyagi Pref. ，Sendai ， Y. Iokawa 5239. Japan ，Fukushima Pref. ，Miyakoji-mura ， Y. Iokawa 5237. Japan ，Fukushima Pref. ，Yabuki-machi ， Y. Iokawa 524 1. Tr 扮lium repens Japan ，Miyagi Pref. ，Sendai ， Y. Iokawa 5243. October October 1996 Journal of Japanese Botany Vo l. 71 No. 5 275 Figs. Figs. 1 -4. FeatUres of trifoliolate leaves at the top of petiole. 1. Kummer ・owia striata. 2. K. stipulacea ， leaf from lower lower part of stem. 3. K. stipulacea ， leaf from upper part of stem. 4. Trifolium repens. 1，lateralleaflet; p， petiole; petiole; pl ， pulvinus of lateralleaflet; pt ，pulvinus of terminalleaflet; r ，rachis; t，terminalleafle t. Scale bars = 500μm. 276 276 植物研究雑誌第71 巻第5 号 平成 8 年 10 月 1.2 1.2 1.1 1.1 E E 1.0 5由咽 0.9 0.8 0.8 0.7 0.7 Z4q回~ 0.6 0.6 坤。 目 £z 0.5 0 .4 0.3 0.3 0.2 0.2 7 8 9 10 11 12 13 14 15 16 17 18 19 Leaf Leaf order Fig. Fig. 5. Variation in length rachis of in relation with order of leaf on main stem. 0: Kummerowia striata ，・: K. st 伊ulacea. Rachises were measured on fully-formed leaves of 10 individuals in each each species. A verages were plotted in each order of leaf ， from 7th to 18th in K. striata and from 9th 9th to 19th in K. st 伊ulacea ，because leaves below were lost and above were not fully-formed in some some individuals. Vertical bars represent standard deviations. Vouchers: K. striata (Y. Iokawa 5239) ， K. stipulacea (Y. Iokawa 5240). stipulacea. stipulacea. The transverse sections of petiole and in the leaf of Kummerowia is shown in Fig. 8A. rachis rachis have two ridges on the adaxial side (Figs. 6A ， When the rachis is very short in upper leaves ，it 6B ，6C ，7A ，7B ，7C) ，whilethatofpulvinusiscircular sometimes doesn't have the three vascular bundles (Figs. (Figs. 6D ， 7D). but only single vascular bundle because the three Both species have similar vascular system. The vascular bundles fuse together at the top of petiole petiole petiole has three m 吋or vascular bundles ，i.e. ，a me- (Fig. 8B). The whole vascular system in such rachis is dian dian bundle and a pair of lateral bundles (Figs. 6A ， similar to that at the top of longer rachis. 7 A). In the top of petiole ， the adaxial part of each lateral lateral bundle enters the pulvinus of each lateral Discussion lea f1 et as a single vascular bundle ， the transverse Th e rachis is the important mo 中hological charac- section section of which shows a continuous arc (Fig. 7E). teristic for distinguishing the pinnately trifoliolate The three vascular bundles are kept through the rachis leaffrom the palmately trifoliolate one. Because each except except at the top (Figs. 6B ， 7B). At the top of rachis ， lea f1 et has ・the pulvinus at the base throughout the the the three vascular bundles fuse into a single vascular Leguminosae (Dormer 1946) ， the terminal lea f1 et is bundle. bundle. and the bundle shows a continuous arc and connected by the rachis and pulvinus with the petiole gradually gradually concentrates in the center (Figs. 6C ， 7C). in the pinnately trifoliolate leaf. The rachis has two This This bundle is kept throughout the pulvinus of termi- ridges on the adaxial side in many leguminous leaves nallea f1 et (Figs.