A NEW RECORD OF BETULA LITWINOWII (BETULACEAE) AND A REVIEW OF THE GEOGRAPHICAL DISTRIBUTION OF THE GENUS BETULA L. IN IRAN H. Zare, M. Akbarinia, S. M. Hosseini, H. Ejtehadi & T. Amini Eshkevari Received 03.08.2010. Accepted for publication10.11.2010. Zare, H., Akbarinia, M., Hosseini, S. M., Ejtehadi, H. & Amini Eshkevari, T. 2010 12 3: A new record of Betula litwinowii (Betulaceae) and a review of the geographical distribution of the genus Betula L. in Iran – Iran. J. Bot. 16 (2): 237-241. Tehran. Betula litwinowii Doluch., discovered from northern Iran, is reported as a new record for the flora of Iran. Morphological characteristics of this species are compared to its closest relative, Betula pendula Roth. In addition, the geographical distribution of these two taxa in Iran and adjacent regions is discussed. Habib Zare (correspondence) and Tayebeh Amini Eshkevari, Herbarium of Nowshahr Botanical Garden, Agricultural and Natural Resources Center of Mazandaran. -Moslem Akbarinia and Seyed Mohsen Hosseini, Faculty of Natural Resources and Marine Science, University of Tarbiat Modares, Tehran. -Hamid Ejtehadi, Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad. Key words. Betula litwinowii, Betulaceae, new record, Iran. Betula litwinowii ! . .# .# $ $ % &' ( ) ) ( *+,- % . ( )( % &' ( ) ) ( *+,. / % . ( )( 0%& ( 9 :)( 3 +2 3 +2 ;) .( 2 ? ' $8) 2 ) .(+' @ (+ = > %( * INTRODUCTION This paper is the outcome of a longer-term revision of the Betulaceae family for the project Flora of Iran (Assadi 1989). At present, there are about 60 species of Betula distributed in most parts of the northern hemisphere, among which Betula pendula Roth. has a wide distribution in Europe and Asia Minor (Krüssmann 1984). The distribution range of Betula pendula covers Europe, eastern Turkey, northern Iraq, northern Iran, western Siberia and Caucasia. Browicz (1972), in the Flora Iranica, family Betulaceae, reported Betula pendula, B. tadzhikistanica V. N. Vassil., B. kunarensis Browicz and B. chitralica Browicz. According to the present revision, of these, Betula pendula is the only species distributed in Iran ) 4 5' ) ( 3 +2 ( ;) ! "# $ % " &'() $ ' $1) % 2 ( ! . $ (# *(+) $% ,- $% /0 .# ) "1 ) 6 7 2 + - 3 Betula litwinowii 3 +2 ) 0 <6 ! .(+' 31) B. pendula ) with known occurrences in the Oshtorak valley, Toochal and Shahrestanak. The latter three species, with Asian origin, are not distributed in Iran. Sabeti (1976) reported Betula pendula from many habitats viz. Taleghan, Shahrestanak, at high elevations in Talar and western Azerbaijan. It seems that Browicz (1972) did not refer to any subalpine stand of Betula of the Hyrcanian region. Later, Browicz (1982, p. 27) stated that Betula pendula in Iran is “very rare, and its few localities are located in the central part of the Elburz, in the province of Mazandaran (above 2000 m a. s. l.).” Therefore, we found it necessary to carry out a detailed investigation on stands of Betula in the Hyrcanian region. Our investigation confirms the presence of IRAN. JOURN. BOT. 16 (2), 2010 Zare & al. 238 Table 1. Some important differences between the two Betula species in Iran. Species Juvenile shoots Petioles Leaves Margin of leaves B. litwinowii Pubescent with Pubescent Pubescent at first Usually frequent glands, and then hairy on simple often sticky lower surface serrate B. pendula Glossy with glands or not Glabrous Glabrous and appearing glossy on both surfaces Betula litwinowii Doluch. in the area and this species is recorded for the first time for the flora of Iran. RESULTS Our revision of the genus Betula in Iran is based on field studies and herbarium specimens collected from Marmishoo (northwestern Iran), Taleghan, Shahrestanak, valley of Lar and Shahrood on the southern slopes of the Elburz Mountains (IranoTuranian region), relatively large stands in the Hyrcanian region including Siahbisheh, Lasikooh, Yakhchalpesht and Dodangeh. Our survey showed that Betula litwinowii is generally distributed in Hyrcanian forests and is different from Betula pendula, which occurs rather in the Marmishoo valley (western Azerbaijan), the northwestern part of Iran, and in Shahrood, easternmost part of the southern slopes of the Elburz Mountains. In addition to ecological differences, the botanical characteristics are different and some of them are described here for Betula litwinowii. Betula litwinowii Doluch. Fig. 1. Tree, 7-15 m tall, bark of old trees whitish with sporadic horizontal gray lines; branches yellowish to reddish. Young twigs pubescent, usually with resinglands. Petioles and young leaves generally pubescent, afterwards more or less pubescent beneath on veins, almost glabrous when adult or occasionally permanently downy. Fruit scale with short and broad lobes; fruit wings 1 to 1.5 x as broad as fruit. Known distribution. Mazandaran: Sari, Sangdeh, 2600 m a. s. l., Assadi, 73639 (TARI). Sari, Sangdeh, Sarcheck, 2700 m a. s. l., Zare and Amini, 4716 (HNBG). Sari, Sangdeh, Naroo, 2650 m a. S. l., Djavanshir and Zare, 10637 (HNBG). Babol, Bandepeye Sharghi, Yakhchaleh pesht, 2470 m a. s. l., Zare, Ejtehadi, Mehdinia, 10168 (HNBG). Amol, Usually double serrate Fruit wings Usually 1-1.5 times broader than fruit Geographical relevance Usually on northern and southern slopes of Elburz Mountains 2-3 times broader than fruit Usually in mountains of northwestern Iran and in the Trans-Elburz Mountains Haraz road, Baladeh, Lasikooh, 2500-2600 m a. s. l., Zare, Rezaee and Naseri, 10612 (HNBG). Amol, Polour, Emamzadeh Ebrahim to Lar dam, 2550-2680 m a. s. l. Zare and Akbarinia, 4102 (HNBG). Chaloos, Chaloos valley, Daryabek, 2400 m a. s. l., Zare, Espahboodi and Khorrami, 10591 (HNBG). –Tehran: Lar valley, 2400 m a. s. l., Assadi and Saniee, 14115 (TARI). The New key for the genus Betula L. in Iran 1. Fruit wings 2 - 3 times broader than fruit. Shoots, petioles and leaves glabrous or with hairs restricted to veins of the lower surface of leaves B. pendula - Fruit wings 1-1.5 times broader than fruit. Shoots petioles and leaves commonly pubescent especially juvenile leaves and shoots of seedlings or saplings. B. litwinowii Betula litwinowii is similar to Betula pendula and differences between the two species are shown in Table 1. Habitat and Ecology. Betula litwinowii has a wide ecological distribution range from moderate and subxeric to humid conditions. It thrives on dry soils with little organic matter to soils rich in organic matter and humus and wet soils in some Hyrcanian forest sites. This species is resistant to a wide range of ecological conditions as found in the southern parts of Sari, Lasikooh and Poloor. Betula litwinowii with Quercus macranthera Fisch. et Mey. constitutes a special association named Querco-Betuletum generally above 2200 m a. s. l. Many woody plants such as Sorbus aucuparia L., Carpinus orientalis Miller, Acer platanoides L., Acer hyrcanum Fisch. & C. A. Mey., Rhamnus cathartica L. and others can be seen in this association (Zare 2002). 239 Betula litwinowii Fig. 1. Betula litwinowii (× 0.55); bracts (×1.2); fruits (×1,6). IRAN. JOURN. BOT. 16 (2), 2010 IRAN. JOURN. BOT. 16 (2), 2010 Zare & al. 240 Map 1. Geographical distribution of Betula litwinowii and Betula pendula in Iran and adjacent regions (the reference for the distribution of the species outside Iran is Browicz & Zielinski, 1982). DISCUSSION Taxonomy and biogeography As noted in the results, fieldwork and study of herbarium specimens showed that Betula litwinowii is a distinct species from another species that was known previously from Iran (Betula pendula). Betula pendula is distributed in northwestern Iran (Marmishoo valley and Silvana; Zagros region and on the southern slopes of the easternmost Elburz mountains in the Shahvar mountain near Shahrood; Irano-Turanian region at 2750 m a. s. l., Herb. No. 78080, TARI). It seems that the distribution range of Betula pendula L. extends from eastern Turkey to the northern parts of Iran (Trans-Elburz Mountains). Based on the current knowledge, the distribution of the species within this range is rather scattered and consists of numerous disjunct populations. On the other hand, the distribution area of Betula litwinowii in Iran is on the northern and some of the southern slopes of the Elburz Mountains, especially in mountainous and subalpine forests of the Hyrcanian region (see Map 1). Further fieldwork will show whether there are morphologically intermediary populations between the Hyrcanian populations and the populations on the southern slopes of the Elburz. Despite Betula litwinowii is a quite distinct species, it is worth mentioning that even if some overlap occurs between some of the characteristics, Betula litwinowii and Betula pendula are easily distinguishable based on the combination of the characteristics. Betula litwinowii, prior to this report, was only reported from the Caucasus region and eastern Turkey, and consequently was considered a so-called Euxinian element. Our new report of the species in the Hyrcanian forests confirms it as an Euxino-Hyrcanian element. Betula pubescens Ehrh. is another species similar to Betula litwinowii. As Yaltrik (1982) and Browicz & Zieleinski (1982) mentioned, this taxon has been reported from northeastern Anatolia as Betula pubescens Ehrh. but true B. pubescens does not occur here, nor does it in the Caucasus (Grossheim 1949). Specimens very similar in size and form of leaves to B. pubescens were discovered in northeastern Anatolia, yet though they are more or less pubescent or puberulent on veins beneath, they lack the axillary tufts so characteristic of B. pubescens. Betula litwinowii is scattered in the Hyrcanian forests and in transitional zones between the Turanian and Hyrcanian phytogeographical provinces, generally above 2200 m a. s. l. (Zare, 2002). A number of highly competitive Hyrcanian woody angiosperms such as Pterocarya fraxinifolia, Alnus subcordata, Acer velutinum, Diospyrus lotus, Gleditschia caspica, 241 Betula litwinowii Parrotia persica, Acer cappadocicum, Fagus orientalis and Carpinus betulus limit the development and growth of Betula litwinowii, which is a light-demanding tree that does not grow very tall. Ecological requirements of Betula litwinowii in Hyrcanian forests are indicative of a stress tolerant species while its competitive ability is lower than in other species. Therefore, high altitude forests and transitional zones are most appropriate for the species’ growth, survival and reproduction. REFERENCES Assadi, M. 1989: Plan of the Flora of Iran. -Tehran. Browicz, K., 1972: Betulaceae in K. H. Rechinger (ed.) Flora Iranica no. 96. -Graz. Browicz, K., & Zielinski, J. 1982: Chorology of Trees and Shrubs in South-West Asia and Adjacent IRAN. JOURN. BOT. 16 (2), 2010 Regions, vol. 1. -Polish Scientific Publishers, Warsaw, PoznaM. Grossheim, A. A. 1949: Opredelitel’ rasteniy Kavkaza [Guide for plants of Caucasus]. -Nauka, Moskva. Krüssmann, G. 1984: Manual of Cultivated BroadLeaed Trees & Shrubs, Vol. I, A-D, p. 220-232. Translated by E. Epp, M., Timber Press. –London. Sabeti, H. 1976: Forests, Trees and Shrubs of Iran. – Ministry of Agriculture and Natural Resources of Iran, Tehran. Yaltrik, Y. 1982: Betulaceae in P. H. Davis (ed.) Flora of Turkey 7: 688-694. –Edinburgh. Zare, H., 2002: Ecological study on Betula in Sangdeh and Lar valley, MSc Thesis. -Tarbiat Modares University, Tehran.