Short notes onPhleumsect.Achnodon(Gramineae)
Scholz, H.: Short notes on Phleum sect. Achnodon (Gramineae). -Willdenowia 29: 45-49. 1999. -ISSN 0511-9618. Micromorphological investigation of the lemma surface revealed that the Mediterranean annual and type of Phleum sect. Achnodon, Ph. subulatum, exhibits a hitherto neglected, unique character combination, which provides strong evidence for an isolated position of this species within the genus. In contrast to recent redefinitions of Ph. sect. Achnodon, the original concept of a monotypical
... pt of a monotypical section is consequently retained. The circumscription and subdivision of Phleum L. is controversial to these days. Depending on the circumscription of both the genus and its species, Phleum comprises 15 (Do8an 1991) to 20 annual and perennial species (Cvelev 1989). Based on macromorphological characters, Phleum was subdivided by most authors (see Do8an 1988: tab. 1) in three sections, viz. Ph. sect. Phleum, sect. Chilochloa (P. Beauv.) Griseb. and sect. Achnodon Griseb., the latter, following Grisebach (1853), regarded as monotypic, only comprising the Mediterranean annual Phleum subulatum (Savi) Asch. & Graebn. (= Ph. tenue (Host) Schrad.). Cvelev (1976) did not agree with this narrow circumscription of Ph. sect. Achnodon and added the annuals formerly placed in Ph. sect. Chilochloa. Do8an (1988) made a different approach, introducing micromorphological structures of the lemma surface and lemma hair type into the taxonomy of Phleum. He redefined Ph. sect. Achnodon as to comprise the species with clavate lemma hairs and added Ph. exaratum Hochst. ex Griseb. and Ph. boissieri Bornm. to Ph. subulatum. Later, Do8an & Us (1996) proposed a new infrageneric classification of Phleum, based on a numerical analysis including both macro-and micromorphological characters, in which Ph. sect. Achnodon comprises all annual species except for Ph. crypsoides (d'Urv.) Hackel and Ph. echinatum Host, which are placed in sections of their own. Unfortunately, the authors did not provide a data matrix with the character states assigned to the species so that an evaluation of their analysis is difficult. The purpose of this contribution is to point out neglected micromorphological features of the lemma surface of Phleum subulatum, which provide additional evidence for the isolated taxonomic position of this species and against the expansion of Ph. sect. Achnodon, which is typified by this species.