A REVIEW OF THE GENUS ALNUS GAERTN. IN IRAN, NEW RECORDS AND NEW SPECIES

جنس توسكا با تعداد حدود 20 گونه، يكي از منابع مهم توليد چوب در نيمكره شمالي است. در جنگل‌هاي هيركاني علاوه بر اهميت اقتصادي فراوان آن، نقش اكولوژيكي منحصر به فردي در بازسازي طبيعي جنگل‌هاي تخريب يافته دارد. همانند بسياري از گونه‌هاي درختي و درختچه‌اي، مشكلات تاكسونوميكي نسبتا زيادي پيرامون شناسايي گونه‌هاي اين جنس وجود دارد. در اين رابطه براي برطرف سازي مسايل موجود، در طي اين تحقيق، تعداد بسيار زيادي از نمونه‌هاي زنده در كنار بررسي نمونه‌هاي هرباريومي از رويشگاه‌هاي مختلف تهيه و مطالعه شد. نتايج مطالعات نشان داد، علاوه بر حضور 2 گونه توسكا در جنگل‌هاي شمال شامل: Alnus glutinosa Gaerth subsp. barbata (C. A. Mey) Yaltrik و Alnus subcordata (C. A. Mey.) Yaltrik به همراه 2 واريته معروف آن، تعداد 2 گونه جديد به نام A. djavanshirii Zare و Zare, Amini & Assadi A. dolichocarpa و يك گونه ركورد به نام A. orientalis Decne. به همراه 2 زير گونه ديگر از توسكا قشلاقي شامل A. glutinosa Gaertn. subsp. glutinosa و A. glutinosa Gaertn. subsp. antitaurica Yaltrik به جنس توسكا در ايران اضافه شده است.

The genus Alnus Gaertn., with approximately 20 species, is of great economic importance and some of the species are as the source of timber in the north hemisphere. In the Hyrcanian forests, the trees of this genus have many critical roles especially in forest rehabilitation. Like most of woody plants in Hyrcanian forests, there are many taxonomic problems concerning the recognition of the species of the genus Alnus in Iran. To cope with, during the long term study on the trees of this genus in the most parts of Hyrcanian forests, many specimens of these trees in the field and in different sites were collected. The studies were performed on living and herbarium specimens and some of the most important local herbarium materials were studied too. According to the previous studies, the genus Alnus in Iran includes two species: Alnus glutinosa Gaertn. subsp. barbata (C. A. Mey) Yaltrik and Alnus subcordata (C. A. Mey.) Yaltrik with two varieties which are distributed in Hyrcanian forests. The results obtained from many specimens of Alnus revealed that there are three extra species and records including: Alnus djavanshirii Zare, Alnus dolichocarpa Zare, Amini & Assadi and Alnus orientalis Decne. as well as two subspecies viz. Alnus glutinosa Gaerth subsp. glutinosa and Alnus glutinosa Gaerth subsp. antitaurica Yaltrik. In this paper, botanical characteristics and ecology of the taxa are elaborated.