B. Papp szerk.: Studia Botanica Hungarica 32. 2001 (Budapest, 2001)

Erzberger, Peter: Ditrichum crispatissimum (Muell. Hal.) Paris, a new species of the Hungarian bryoflora, and Ditrichum flexicaule (Schleich. ex Schwaegr.) Hampe in Hungary

DISCUSSION In this paper, FRISVOLL'

s concept (1985) of two species making up the Ditrichum flexicaule complex was applied to the specimens collected in Hungary housed in BP. Although the majority of specimens could be named without problems, some were found to be intermediate, in that they approach D. crispatissimum in some character states, while in others they exhibit typical features of D. flexicaule. Frisvoll's concept has been applied by other authors to different regions of Europe. While CASAS et al. (1990) succeeded in sorting out Spanish specimens into Frisvoll's taxa, other authors admit difficulty (SMITH 1993) or report similar results with respect to seemingly intermediate forms (NOVOTNY 1997). Smith disagrees with Frisvoll on the usefulness of some characters, and in respect to one very important feature - flexuosity of leaves - he even contradicts Frisvoll's result. Since this point, which is also related to the meaning of the specific epithet "crispatissimum", is considered very essential, it will be discussed here at some length. According to FRISVOLL (1985), the leaves of the type of D. crispatissimum "are rather strongly crisped (...), probably because it grew in a sheltered place.

..". But this is not typical of the taxon as conceived by Frisvoll! In general, its leaves are "usually slightly or not flexuose (except in some sheltered habitats), ..., often falcate", whereas the leaves of D. flexicaule s. str. are "usually flexuose, rarely falcate" (Table 2 in FRISVOLL 1985; emphasis added by P. E.). This is in agreement with earlier comments, e.g. in NYHOLM (1954) on D. flexicaule var. sterilis De Not. (a synonym of D. crispatissimum: "leaves almost straight, ... when dry, leaves are not crisped"), and D. flexicaule ("leaves ... crisped when dry"), as well as in TUOMIKOSKI etal. (1973), stating that leaves in D. giganteum Williams (another synonym of D. crispatissimum) "are not characteristically bent to somewhat crisped when dry", and in D. flexicaule are "somewhat crisped when dry". It is also in agreement with the observations of the author on British, Irish and French specimens including D. crispatissimum. SMITH (1993), on the other hand, states that dry leaves in D. crispatissimum are "usually flexuose" (p. 45), and a second time "often flexuose, sometimes secund" (p. 51), whereas in D. flexicaule they are "rarely flexuose or secund". He does not seem to have noticed the discrepancy between his and Frisvoll's statements, since he does not comment on this matter. Although the other character states listed by SMITH (1993) are in agreement with FRISVOLL (1985), leaf crispness is a very characteristic feature differentiating D. flexicaule and D. crispatissimum macroscopically, and since SMITH (1993) also states that "95% of speci-