B. Papp szerk.: Studia Botanica Hungarica 29. 1998 (Budapest, 1999)

Erzberger, Peter: Distribution of Dicranum viride and Dicranum tauricum in Hungary

Using magnifications between 20-40 times, it is often possible to detect protonema-like threads of cells growing from the broken ends of D. tauricum leaves, a feature not observed in D. viride. Sometimes, the broken tips and the protonema form a real felt at the base of the tuft. An easy and reliable way to distinguish the two species microscopically depends on the differences in the length of lamina cells (HEGEWALD 1972a, b): In the transverse section of leaves, several distinguishing features can be observed. The lamina of D. viride is partially bistratose in the upper part, whereas the lamina of D. tauricum is unistratose throughout. The nerve of D. viride exhibits dorsal stereids; these are absent in D. tauricum (Fig. 2). DISCUSSION Dicranum viride is classified as "vulnerable" in the Red Data Book of European Bryophytes, it is also included in Appendix I of the Bern Convention and in Annex 2 of the EC Habitats and Species Directive (SCHUMACKER and MARTINY 1995). At present, threatened species of this kind attract the attention of bryologists concerned with the protection of nature in Europe (e.g. ENROTH 1989). The first aim is to assess the distribution of these species as accurately as possible. SCHUMACKER and MARTINY (1995, map 18) also present a map showing the distribution of D. viride in Europe. It shows only two points for Hungary, Fig. 2. A = Part of transverse leaf section of Dicranum viride (Herbarium Z. Tóth, Budapest, Hungária, No. 1989 1105.023. Flora Hungarica. Bátorliget TVT, Nyírláp, nyírfa törzsén, 3b erdőrészletben, Alt.: 130 m, Dat.: 1989.XI.4. leg. K. Barabás, Z. Tóth). - B = Transverse leaf section of Dicranum tauricum (Herbarium P. Erzberger, Berlin, Nr. 4227. Budapest, Hárshegy, Totholz, liegender Stamm unterhalb "Kilátó", 9. April 1998 leg. P. Erzberger) Scale bar: 100 pm. (drawn by P. Erzberger).