B. Papp szerk.: Studia Botanica Hungarica 35. 2004 (Budapest, 2004)
Wojtal, A.; Buczkó, Krisztina: Comparative study of Navicula hasta and N. rakowskae: their morphology and distribution
and should be re-investigated. In this case all documented reports (or materials deposited in herbaria) should be compared with lectotypified material. The reliability of other reports is very limited. Comparing the material studied with data from the literature we observed a morphological similarity of the population of N. hasta from Bodos and the population from Köpecz, which has been illustrated by LANGE-BERTALOT (2001). These populations are similar in respect of valve outline, arrangement of striae, and other ultrastructural features, and partially overlap the original diagnosis by Pantocsek (Table 1). However, some of the specimens observed by us were of larger size and had a lower number of striae in 10 pm. It is also uncertain if the known holotype was originally designated by Pantocsek (KRENNER 1980). The specimen known as the holotype differs from our material, Pantocsek' s description, and data in the literature (Table 1, Figs 1-4), and its value as the holotype is questionable. Despite an extensive search of Bodos material we have not found any specimen that more closely matches the holotype. Because the present concept of N. hasta is unclear (Pantocsek cited in his protologue illustrations of two specimens (syntypes), which do not conform with the holotype specimen. Therefore in our Table 1 (continued) Navicula hasta N. rakowskae central area small, elliptic irregularly wid- small, elliptic variable outline expanded distinct, irregular, ened more or due to the more or less transapically formed by graduless shortened ally or irregulary transapically striae shortened middle striae arrangement "ad centrum longiores et central area formed by striae more distantly striae more disof striae in the reviores" the central formed by al- shortened al- spaced tantly spaced middle part of area formed by longer ternately Ion- ternately the valve and shorter striae ger and shorter striae irregustriae more larly distantly spaced
