PHLOROGLUCINOL DERIVATIVES IN DRYOPTERIS SECT FIBRILLOSAE AND RELATEDTAXA (PTERIDOPHYTA, DRYOPTERIDACEAE)

The phloroglucinol compositions of 18 species (including subspecies) b elonging to Dryopteris Adanson sect. Fibrillosae Ching have been inves tigated on a world-wide basis, and the taxonomic implications discusse d. The main emphasis is on D. affinis (Lowe) Fraser-Jenkins, its subsp ecies and varieties, as well as on D. wallichiana (Sprengel) N. Hyland er and its relatives. The phloroglucinols of the ferns of sect. Fibril losae proved to be remarkably constant in most taxa: large amounts of flavaspidic acids (5) and slightly varying amounts of filixic acids (1 9) were found in virtually all taxa. Traces or small amounts of norfla vaspidic acids (4), albaspidins (10), oligoflavaspidic acids (23, 26) and tetraalbaspidins (25) occur as well. Only D. acutodentata Ching an d D. affinis subsp. borreri (Newman) Fraser-Jenkins, both partly deriv ed by crossing with species outside the section, differ clearly from t he other taxa in containing para-aspidins (7) and trispara-aspidin (20 ), while D. fusco-atra (Hillebrand) W. Robinson shows a different phlo roglucinol pattern altogether. The high levels of similarity between t axa may reflect their common origin from a few diploid apomictic taxa by hybridization with sexual diploids. The different subspecies and va rieties of D. affinis showed very similar phloroglucinol spectra excep t for subsp. borreri. The triploid apogamous subspecies cambrensis Fra ser-Jenkins, pseudo-disjuncta (Fraser-Jenkins) Fraser-Jenkins and pers ica Fraser Jenkins may have evolved from the diploid apomictic subsp. affinis and D. oreades Fomin of sect. Dryopteris, whereas the triploid apogamous subsp. borreri may have its origin from subsp. affinis and D. caucasica (A. Braun) Fraser-Jenkins & Corley of sect. Dryopteris. T he precursor of apomictic diploid D. wallichiana subsp. wallichiana is discussed. Dryopteris crassirhizoma Nakai, a diploid sexual species f rom Japan in sect. Fibriollosae, is suitable from a chemical point of view, but not from its morphology. Dryopteris conjugata Ching in sect. Hirtipedes Fraser-Jenkins initially appeared to be suitable both in m orphology and chemistry, provided that norflavaspidic acid (4) was bio transformed to flavaspidic acid (5) in D. wallichiana subsp. wallichia na as suggested in the present work. However, cytological investigatio n of one accession of this species has shown it to be diploid but apom ictic, and therefore inappropriate as a sexual diploid ancestor of the diploid apomictic D. wallichiana subsp. wallichiana. Five new taxa ar e described: Dryopteris wallichiana subsp. reichsteinii Fraser-Jenkins , D. affinis subsp. affinis var. jessenii Fraser-Jenkins, D. affinis s ubsp. affinis var. kerryensis Fraser-Jenkins, D. affinis subsp. cambre nsis var. insubrica Fraser-Jenkins and D. affinis subsp.pontica Fraser -Jenkins.