EDINB. J. BOT. 54(2): 183-216(1997) 183 FRUIT MORPHOLOGY, ANATOMY AND TAXONOMY OF TRIBE NEPETEAE (LABIATAE) A. L. BUDANTSEV* & T. A. LOBOVA* The results of a detailed SEM study of nutlet morphology in 156 species of tribe Nepeteae (Labiatae) are presented. Two main types, smooth and sculptured, are described; within them such subgroups as reticulate, cellular, verrucose and tuberculate are defined. The taxonomic significance of these characters is discussed. Pericarp structure was investigated in 34 species. Mucilaginous tubercles were found on the surface of the nutlets in Nepeta, Drepanocaryum and Lophanthus, and their structure is described. In the 10 genera of this widespread tribe, three informal generic groups are recognized, based on a combination of nutlet morphology, pericarp structure and vegetative and floral features. Keywords. Drepanocaryum, Lophanthus, Nepeta, nutlet morphology, pericarp structure. INTRODUCTION Nutlet morphology in the Labiatae has proved useful to varying degrees at different levels of the taxonomic hierarchy. Bentham (1848), who laid the foundations of the classification of the family, used some nutlet characters in the diagnoses of some tribes. They were taken into consideration in subsequent treatments of the Labiatae (Briquet, 1895-1897; Wunderlich, 1967) and of genera and species (Bilimovitsch, 1935; Wojciechowska, 1958, 1961a,b, 1966; Hedge, 1970; Rejdali, 1990; Ryding, 1992a,b). The tribe Nepeteae differs from the rest of the Labiatae in that the posterior (upper) pair of stamens are longer than the anterior (lower). It includes c.ll genera and 360 species (Budantsev, 1992b) found in most parts of Eurasia and North America. The importance of the morphology of nutlet surfaces has already been demonstrated for Nepeta (Hedge, 1962, 1992; Hedge & Lamond, 1968; Rechinger, 1982a; Ubera, 1982). Hedge (1962), using some nutlet characters in the taxonomy of species allied to N.fissa C.A. Mey., recognized three basic types of nutlet texture: smooth without tubercles, 'flatly' tuberculate and clearly tuberculate, which were all constant features in mature nutlets. A study of nutlets in Afghanistan Nepeta species showed little variation in their morphology within a species but frequently significant differences between species (Hedge & Lamond, 1968). Makarova (1967) showed differences in anatomical structure of the nutlets between some genera of tribe Nepeteae. In recent times the importance of the SEM in the study of nutlet surfaces has been demonstrated for various genera of Labiatae (Hussain et al., 1990; Paton, 1990; Rejdali, 1990; Ryding, 1992a,b; Budantsev, 1993c,d). Ubera (1982) studied the nutlet surface of 12 Nepeta species in the Iberian Peninsula. * Komarov Botanical Institute, 2 Popova Street, St Petersburg 197376, Russia. 184 A. L. BUDANTSEV & T. A. LOBOVA The study of myxocarpy (the formation of mucilage when nutlets become wet) has been established as a separate area of research in the carpology of the Labiatae. The phenomenon of myxocarpy in this family was first described by Wagner (1914). Hedge (1970) investigated mucilaginous cells in several species of the genus Salvia and described features of their structure and formation patterns of the mucilage; he also found that characters of myxocarpy could be used in the systematics of this genus. The presence of myxocarpy has also been reported in many representatives of the family from various subfamilies and tribes (Ryding, 1992a,b; 1993a,b; 1995). MATERIALS AND METHODS This study is based on nutlets taken from herbarium specimens, mostly from LE and BM, E, G, K and W, and from original collections made during expeditions to Middle Asia, Russia, Caucasus and Mongolia. For SEM studies the nutlets were coated with sputtered gold. For pericarp anatomy studies dry nutlets were placed for 10 days in a mixture of distilled water, 96% ethanol and glycerol taken in equal proportions. In the middle part of nutlets cross-sections lOum thick were made using a freezing microtome. These sections were stained with a 10% aqueous solution of gentian violet and embedded in glycerol. The presence of mucilage on the nutlet surface was determined by the method of Ryding (1992b) based on the extent of swelling of mucilaginous cells when the nutlet became wet. There were four types of reaction: a strong mucilaginous reaction (with mucilaginous cells 0.8-1.5mm long), a moderate reaction (with cells 0. l-0.5mm long), a weak reaction (with mucilaginous cells less than 0.1mm long) and a very weak reaction when no appreciable elongation of mucilaginous cells occurred after swelling in water. RESULTS Nepeta L. This is the largest genus of tribe Nepeteae, with 210 species (Budantsev, 1993a). It occurs in most parts of Eurasia, except the Arctic. It is a difficult genus taxonomically due to the paucity of reliable characters, hybridization and introgression. According to the traditional classification of Nepeta (Bentham, 1832-1836, 1848; Boissier, 1879; Briquet, 1895-1897; Pojarkova, 1954), this genus is divided into sections based on habit, leaf, inflorescence, calyx and corolla structure and nutlet characters. The boundaries between most sections are indistinct although there are some clear-cut ones (Oxynepeta Benth., Micronepeta Benth., Orthonepeta Benth. etc.). Nutlets of 92 species were examined. Their size is 1-3 x 0.5-1.5mm; they are elliptic, ovate or obovate, trigonous or rounded-trigonous in transverse section, and apically rounded or truncate, with a whitish lateral straight or bilobed areole (Fig. 1A, C; Fig. 2A, C). The nutlets in N. brachyantha Rech.f. & Edelb. have a prominent U- or V-shaped areole extending c.2/ of the nutlet length. N. leucolaena 3 Benth. ex Hook.f., N. pilinux P.H. Davis and some other species have nutlets with NUTLET MORPHOLOGY IN TRIBE NEPETEAE 185 FIG. 1. Nutlets of Nepeta. A, Nepeta linearis; B, N. daenensis; C, D, N. fordii; E, N. formosa; F, N. sibirica; G, N. lasiocephala; H, N. wettsteinii. Scale bars= 10(im (except A, C = 100|xm). 186 A. L. BUDANTSEV & T. A. LOBOVA an apical tuft of multicellular simple hairs, and in N. latifolia DC. and N. nuda L. they are apically papillate. Similar thin hairs occur in N. cataria L. in very young nutlets but later they are absent. In Nepeta two main types can be recognized based on surface ornamentation: smooth and sculptured. Within these types, variants can be recognized. The smooth nutlets have three variants: 1. Undulate (Fig. 1A, B): characterized by a thick cuticle masking the cell structure in the central area of the nutlets; under high magnification cellular reticulations can be seen at the apex. These cells are oblong with straight, not or slightly raised anticlinal walls (AW). The external periclinal walls (EPW) are flat or slightly depressed, smooth or fine-granular. 2. Reticulate (Fig. 1E-G): consists of oblong, rounded or polygonal cells. The AW are straight and of variable thickness. The EPW are flat or depressed, striate- furrowed or ridged. Reticulate-cellular (Fig. IE, F) and ridged-cellular (Fig. 1G) surfaces appear as varieties of the reticulate pattern. The former has more prominent AW and depressed EPW; the latter is distinguished by irregular cells with undulate and prominent AW. 3. Bead-like pattern (Fig. ID): has indistinctly shaped cells with small protuberances on the AW. The EPW are depressed, fine striate-furrowed. Sculptured nutlets are characterized by having rounded or cone-shaped tubercles which occur on all surfaces, especially towards the apex. The epidermal cells of the pericarp appear rounded and polygonal, generally with prominent AW. The EPW are flat, depressed or convex, furrowed or striate-furrowed. Four variants can be recognized based on the shape of the tubercles: 1. Verrucose (Fig. 2A, B): shows tubercles formed by the ring of convex radial cells. The centre of these tubercles is mostly depressed. The papillate-verrucose texture (Fig. 2F) with papillae on the edges of the nutlets can be considered as a variant of the verrucose pattern. 2. Tuberculate (Fig. 1H): differs in that the tubercles have a convex or truncate apex forming one or more layers of radial cells. 3. Tuberculate-cellular (Fig. 2E): the tubercles have a flat apex and oblong or rounded cells with a raised AW and depressed EPW. 4. Thorn-like pattern (Fig. 2C, D): characterized by oblong or cone-shaped tubercles with a rounded or truncate apex. Pericarp structure has been investigated in 15 species (marked by asterisks in Table 1). Pericarp thickness varies from 30um in N. podostachys to 170um in N. amethystina. Myxocarpy is found in four species. A moderate mucilaginous reaction occurs in N. micrantha and N. trautvetteri. N. glomerulosa and N. amethystina show a very weak reaction. NUTLET MORPHOLOGY IN TRIBE NEPETEAE 187 FIG. 2. Nutlets of Nepeta and Dracocephalum. A, Nepeta glomerulosa; B, N. amicorum; C, D, N. stenantha; E, iV. involucrata; F, iV. i«avw; G, H, Dracocephalum multicolor. Scale bars = 10nm (except A, C= 100|im; G= 1000^m). Source of material Altai, near Ongudaj Valley, 1986,Budantsev s.n. (LE)Far East, Shkotov distr., Transhel1050, 1053 (LE)Tibet, Ta-Tsien-Lou, Soulie 484,816, 573 (E)Kashmir, Shagazthang, Duthie12130 (LE)Fergana, in Mailisu Valley,Budantsev 109 (LE) Ichang, ix 1886, Henry s.n. (LE) Pamir, in Pshart Valley, Budantsev270 (LE) Pamir, in Shah-Dara Valley,Budantsev 219 (LE) Kara-Bulak, Bochantsev 120 (LE) Kashmir, Gilgit, 1887, Duthie s.n.(LE)Kashmir, Srinagar, Clarke 29081(LE) ar ar ar ar ar Pattern reticulate-cellul reticulate-cellul reticulate-cellul reticulate-cellul reticulate-cellul bead-like ridged-cellular reticulate verrucose undulate undulate a, ongoli alaya alaya, M m m eta L. Distribution S Siberia, E Kazakhstan, ChinaFar East, E China China (Tibet, Sichuan) Himalaya, China (Tibet) Tian-Shan HsuanSW, SE China Pamir, Afghanistan, W Hi tz.Budantz.Pamir, Afghanistan, W HiChina (Tibet) Budantz.z.Pamiro-Alaj W Himalaya Afghanistan, Himalaya TABLE 1. Nutlet surface in Nep Sect., species Sect. Macronepeta Benth.N. sibirica L.* N. manchuriensis S. Moore N. souliei H. Lev. N. leucolaena Benth. N. formosa Kudr. Sect. Appendiculatae C.Y. Wu & N. fordii Hemsl. Sect. Glechomanthe Pojark.N. longibracteata Benth.* Sect. Brachystegiae (Pojark.) A.L. N. glutinosa Benth. Sect. Catanthertae (Pojark.) A.L. N. subhastata Regel Sect. Spicatae (Benth.) Pojark.N. connata Royle ex Benth. N. linearis Royle ex Benth. Kashmir, Nafraw, Stewart 12742(LE)Dalhousie, ix 1874, Clarke s.n. (LE)Kashmir, Dras, Duthie 13744 (LE) Pamiro-Alaj, Darwaz, Budantsev470; Pamiro-Alaj, Anzob, Budantsev824 (LE)Afghanistan, Kapisa, Panjir-Tal,Podlech 12854 (LE)Kapisa, Podlech 12490 (LE)Anzob, Budantsev 826 (LE)Uzbekistan, Tashkent, Ugam, Z. vonMinkviz 778 (LE)Afghanistan, Kapisa, Podlech 12288(LE)Tian-Shan, in Itagar Valley,Budantsev 85; Pamiro-Alaj,Dzhelandy, Budantsev 599 (LE)Pamir, Shugnan, Budantsev 302;Pamir, Vahan, Budantsev 403 (LE)Ex horto Petropol. Herb. Meyer(LE)Kellal et Ssebsekuh, 1868,Haussknecht s.n. (G) Pamir, Shah-Dara, Budantsev 367;Iran, Yezd, Mehriz, v 1849, Buhses.n. (LE)Pamir, Shah-Dara, Budantsev 368(LE)Pamiro-Alaj, Zeravshan, Zibansai,Drobov 367 (LE) ar undulate undulateundulate undulate undulate ridged-cellularridged-cellularridged-cellular ridged-cellular ridged-cellular undulate ridged-cellular reticulate-cellul undulate undulate undulate mir mir a, h h y n W Himalaya, China (Tibet) Himalaya Afghanistan, Himalaya, China (Tibet)Pamiro-Alaj, Afghanistan, Kas Pamiro-Alaj, Afghanistan, Kas AfghanistanPamiro-AlajPamiro-Alaj Afghanistan, W Himalaya Tian-Shan, Pamiro-Alaj Pamir, Afghanistan, W HimalaChina (Tibet)Iran Iraq (east), Iran (west) Iran, Pamiro-Alaj, Afghanistan Pamir, Afghanistan, W Pakista Pamiro-Alaj, Afghanistan n. k s s h. h.h. au N. nervosa Royle ex Bent N. elliptica Royle ex BentN. discolor Royle ex Bent N. podostachys Benth.* A', subincisa Benth. N. pubescens Benth.TV. tyttantha Pojark.N. alatavica Lipsky Hook.f.N. clarkei N. bucharica Lipsky* N. pamirensis Franch. TV. crispa Willd. N. chionophila Boiss. & H Sect. Micronepeta Benth.N. bracteata Benth.* N. daenensis Benth. N. jacubii Lipsky Source of material Iran, Ecbatanens, Pichler 1882 (LE) Pamiro-Alaj, near Leninabad, ix1989, Budantsev s.n. (LE)Afghanistan, Bamian, Podlech12077; Badakhshan, Podlech 12431(LE) Persia, Ghilan, Th. Alexeenko 471(LE)Iran: Tehran: Vardavard, Wendelbo& Sanii 12588 (LE)1837, Aucher-Eloy s.n. (G)Iran: Damghan-Semnan, Behboudi,Aellen 780 (LE)Teheran, Foroughi & Assadi 18030(LE)Persia austr., Kuh-Daena, Kotschy757 (LE)Daghestan, Kurush, vii 1986,Menitsky et al. s.n. (LE) NW India, Royle s.n. (LE)Chitral, R.R. Stewart 2405 (LE)Nangarhar, Torkham, Hedge et al.W-7437 (GB) ar Pattern undulate reticulate reticulate-cellul ridged-cellular reticulate reticulateridged-cellular reticulate ridged-cellular ridged-cellular verrucoseverrucoseverrucose a, y ala aya Distribution Iraq (east), NW Iran Tian-Shan, Pamiro-Alaj,AfghanistanPamir, Afghanistan, HimChina Iran (Elburs) Iran (Elburs) Iran (Kuhrud)Iran (Elburs) Iran (Elburs) Iran (centre) Caucasus E Afghanistan, W HimalPakistan (Chitral)E Afghanistan z. nt ojark. Buda ech.f. TABLE 1. (continued). Sect., species N. petraea Benth. Sect. Capituliferae (Benth.) PN. olgae Regel* JV. floccosa Benth. Sect. Denudatae (Briq.) A.L. A', denudata Benth. N. cephalotes Boiss. N. prostrata Benth. Rech.f.N. eremokosmos N. gloeocephala Rech.f. N. lasiocephala Benth. N. supina Stev. RSect. Sparthonepeta (Briq.)N. distans Royle ex Benth.N. schmidii Rech.f.N. amicorum Rech.f. Afghanistan, Griffith 4007 (LE)Afghanistan, Konar, Hewer 1370(LE)Kurram, Harsukh 15441 (LE)Persia, Kerman, Bornmuller 5124(LE) Badahshan, Anderab, Ikonnikov3936 (LE)Darwaz, Obi-Harak, Popov et al.1204 (LE) Turkey, Hakkari, Davis 45326 (LE)Antalya, Kemer, Davis 15219 (LE) Tian-Shan, in Itagar Valley,Budantsev 22; ad Budapest,Hungary, Bemoitzky 405 (LE)Pyrenees orientalis, 1952, Pavilions.n. (LE) Pamiro-Alaj, Ganshino, Budantsev758; Herzegovinae, Nevesine, Velez227 (LE)Iran, Fars, Darreh, Wendelbo &Foroughi 17537 (LE)Tiflis, Wittmann 11 (LE)Daghestan, Kurush, 1988,Medvedeva s.n. (LE) e s o c u r r verrucosetuberculate papillate-veverrucose verrucose verrucose thorn-liketuberculate tuberculate tuberculate reticulate thorn-like thorn-likethorn-like al) E Afghanistan, W PakistanE Afghanistan, Pakistan (Chitr E Afghanistan, W PakistanIran, Afghanistan, W Pakistan ntz.Pamiro-Alaj, NW Afghanistan Pamiro-Alaj SW Europe, SW AsiaTurkey From W Europe to C Siberia France, Spain From W Europe to Japan Iran, Afghanistan Turkey, Iran, CaucasusCaucasus a d u B N. rugosa Benth. Rech.f. & Edelb.N. brachyantha N. suavis StapfN. glomerulosa Boiss.* Sect. Kudrjascheviae (Pojark.) A.L. N. korshinskyi Lipsky N. grubovii (Kochk.) A.L. Budantz. Rech.f.Sect. Macrostegiae (Boiss.)N. italica L.N. phyllochlamys P.H. Davis Sect. Orthonepeta Benth.N. nuda L.* N. latifolia DC* Sect. NepetaN. cataria L.* N. persica Boiss. N. betonicifolia C.A. Mey*N. cyanea Stev. Source of material Wendelbo &Iran, Mazandaran,Assadi 13328; Azerbajdzhan, Lerik,Menitsky & Popova 11 (LE)Cilicia, Kotschy 510a (LE)Near Jerusalem, Zohary &Amdursky 174 (LE)Ex Horto Petropol., vi 1873,Maximowicz s.n. (LE)Abyssinia, inter Gernamora etSabra, Schimper 720 (LE)Beni-Mellal, Davis 55194 (E); propeBemanot, 1879, Rat s.n. (LE)France, Lux-la-Croix, Barbezat 6135Spain, Alicante, Willkomm 443 (LE) Tian-Shan, Turajgyr, vi 1953,Goloskokov s.n.; Kazakhstan,Betpakdala, vi 1949, Goloskokov s.n.(LE)Iran, Khoi, Furse 2273 (LE)Iran Esfahan: Taleghan, Wendelbo &Foroughi 11543 (LE)Iraq, Avroman, 1867, Haussknechts.n. (LE)Persia, Dervarin, Bunge s.n. (LE)In monte Kuh-i-Hasar, Bornmuller5125 (LE)Bamian, Ajar, Rechinger 16636 (G)Zendianab (Bienal), Knavn s.n. (B) e e e e e e e eee Pattern thorn-like thorn-like thorn-like thorn-like thorn-like tuberculat tuberculat thorn-like tuberculat tuberculat tuberculat tuberculat tuberculat tuberculattuberculattuberculat s u s e as Distribution E Iraq, Turkey, Iran, Caucasu Turkey (east) W Mediterranean NE Africa Africa (Ethiopia) Africa (Morocco) W Europe W Europe, NW Africa E Europe, Kazakhstan, MiddlAsia, W China, W Mongolia Turkey (east), Iran, Transcauc Iran, Turkmenia E Iraq, Iran Iran, Turkmenia, Afghanistan Iran (Kerman) Afghanistan (centre) E Iraq, NW Iran k. ABLE 1. (continued). ect., species V. racemosa Lam. V. stenantha Kotschy & Boiss.V. curviflora Boiss. V. azurea R. Br. ex Benth. V. biloba Hochst. ex Benth. V. atlantica Ball V. nepetella L. V. amethystina Poiret* ect. Micranthae (Boiss.) PojarV. micrantha Bunge* V. meyeri Benth.V. saccharata Bunge V. humilis Benth. V. ispahanica Boiss.V. bornmuelleri Hausskn. V. rechingeri HedgeV. wettsteinii H. Braun T S T TT T T T T T ST TT T TT TT