A cytotaxonomic survey of the ferns and fern allies of Australia (including Lord Howe Island) is presented. Five-hundred-and-twenty-six chromosome counts of 268 Australian species, subspecies, varieties, variants and hybrids are recorded, only a small number having been previously investigated by other botanists on Australian material. Diploids represent c. 62% of the counts on species and c. 38% on polyploids, the latter ranging principally from triploids to a single decaploid and dodecaploid (but no heptaploids). More than one ploidy level has been reported in 19 taxa (almost 8% of taxa). Counts of 10x for Asplenium aethiopicum and 12x for A. flabellifolium are the highest definite ploidy levels for the Australian pteridophyte flora. Chromosome counts for 29 families and 89 genera are cited. Only diploids were reported for Osmundaceae and Cyatheaceae, but only polyploids for the Psilotaceae, Vittariaceae and Ophioglossaceae. An analysis is given of the levels of ploidy in 248 taxa, excluding the Lycopodiaceae and Hymenophyllaceae. The percentages of diploids and polyploids in Australian species are compared with those of nearby countries. Many species reported on here have never been cytologically investigated before, while others have not been studied previously on Australian material. The following genera have been examined cytologically for the first time: Coveniella Tindale, n = 41; Paraceterach (F.Muell.) Copel., n = 29; 'Oenotrichia Copel.', 2n = 82 (2x); Revwattsia (Watts) D.L.Jones, 2n = c. 328 (8x); and Pteridoblechnum Hennipman (2n = 54). The phylogeny of the genera is discussed in the light of these findings. Certain families such as the Adiantaceae, Cyatheaceae, Hymenophyllaceae, Lindsaeaceae and Marsileaceae were given special attention by collecting as much living material as possible. A number of species-complexes has been found and further chromosome counts added to intercontinental species complexes. The Dopp-Manton and Braithwaite forms of reproductive apomixis have been reported amongst some genera. Endemism, hybridity and apogamy amongst Australian pteridophytes are discussed, as well as homosporous and heterosporous species. The new combination Phymatosorus membranifolius (R.Br.) Tindale is made.

A cytotaxonomic survey of the Pteridophyta of Australia

The distribution and origins of selected Pteridophyta in the Mediterranean area is discussed. Five main periods and sources are indicated: ancient taxa in Equisetopsida and Lycopodiopsida which had an early Laurasian origin; Polypodiopsida that evolved in deciduous forest of the Northern Hemisphere in Paleocene- Eocene times; elements that arose in the tropics of the Cretaceous-Paleocene flora and developed in the warmer and wetter periods to be residual in the south-west of our area; those later species that secondarily spread from east or south-west Asia. The importance of Gondwanaland as a source of some of the older taxa is also briefly discussed.

Origin and distribution of Pteridophytes in the Mediterranean area

Spores of species of Hemionitis, Gymnopteris, and Bommeria were compared for 1) presence of perispores using the sodium hydroxide assay, 2) surface structure of mature perispores and exospores, and 3) development of superficially similar mature perispores. All taxa were shown to possess perispores and greater morphological variation was detected within and among species than previously reported. On the basis of shared morphological and ontogenetic features, groups of species were identified that crossed presently recognized generic boundaries; hence, the existing trigeneric classification is inadequate to depict natural relationships among these taxa. The results also demonstrate that superficial similarity of mature perispores may not be the best indicator of systematic relationship among species, as similar surface patterns may be derived through different developmental pathways.

Spore morphology and generic delimitation of new world hemionitis, gymnopteris, and bommeria (adiantaceae)

The spore morphology of Cheilanthes and Astrolepis species from northwestern Ar- gentina was analyzed using light microscopy and scanning electron microscopy. Three patterns of sporoderm structure were found: two exclusive and different structures in A. sinuata and the C. squamosa group, and a typically cheilanthoid structure with diverse sculptures in the rest of the species of Cheilanthes, i.e., C. bonariensis, C. buchtienii, C. cf. cucullans, C. obducta, and C. volcanensis. Sporophytic features such as hairs with "tongue and groove" wall cells and dixylic vascular strands are also mentioned in C. obducta. Similar spore characteristics are correlated with sporophyte morphology in some of the recognized groups. Spore-size differences, abnormal- ities in spore type, abortion and number of spores per sporangium (16, 32) suggest polyploidy and/or apogamy in some specimens of C. buchtienii, C. obducta, and C. squamosa, and in all samples of A. sinuata and C. bonariensis. The present paper is the second in a series of studies on cheilanthoid ferns preliminary to an ongoing project, "Atlas of Spores of Pteridophyta of North- western Argentina" (Morbelli, in prep.). Perispore structure and stratification offer some interesting substructures and variations. Previous papers (Ranker, 1989; Tryon and Lugardon, 1991) have shown that detailed analysis of the exospore and perispore can provide valuable information in cheilanthoid ferns. The aim of these papers is to characterize each species of the region from the palynological point of view and to assess whether spore morphology is useful in the systematics of the group. When necessary, sporophytic features are included for comparative analysis of species groups.

https://www.jstor.org/stable/info/1547536

Palynological Study of Cheilanthes and Astrolepis (Pteridaceae) Species from Northwestern Argentina

509 Chambers, T.C & Farrant, P.A. (Royal Botanic Gardens, Sydney, NSW. Australia) 2000) 1991. A re-examination of the genus Cheilanthes (Adiantaceae) in Australia. Telopea 4(3): 509-557. The taxonomy of the Australian species of Cheilanthes has been further revised following the availability of a much greater number of specimens, especially from northern Australia, since the revision of this genus in Australia by Quirk et al. in 1983. We describe one new species (C adiantoides) and recognise 14 other species, one of which has two subspecies. Two of the 15 taxa recognised by Quirk et al. are reduced to synonymy. We clarify the taxonomy of the northern Australian species, and recognise one of the four species described recently by D.L. Jones. Two of the three taxonomic changes proposed by P.S. Green in 1988, one new combination and one change of authority, are accepted. Scatter diagrams are used to compare characters of specimens in what are believed to be closely related taxa. The distribution of each species is mapped and a key for their identification provided. The diagnostic characters found to be most useful for separating the Australian Cheilanthes were the degree of frond division, and the length and density of hairs and scales, on stipe, rhachis and upper and lower pinnule surfaces; spore characters were useful for some but not for all species. Although the breeding behaviour of Cheilanthes was not investigated per se in this study, new data on variability in spore number and spore size suggest that both hybridisation and apomixis are occurring in some populations and variation from hybridisation is contributing to the difficulty of defining some species.

/pdf/a-re-examination-of-the-genus-cheilanthes-adiantaceae-in-c3xc89c4vt.pdf

A re-examination of the genus Cheilanthes (Adiantaceae) in Australia

The fern genus Cheilanthes Sw. in Australia consists of 15 taxa. The range of variation of each species is discussed and the distribution presented in map form. Cheilanthes sieberi Kunze is recognized as having two subspecies, C. sieberi subsp. sieberi stat. nov, and C. sieberi subsp. pseudovellea Quirk & Chambers. Three long-overlooked species are now recognized and defined; they are C. nudiuscula (R.Br.) T. Moore, C. tenuissima Bailey and C. contigua Baker. Cheilanthes vellea (Aiton) F. Muell. is now recognized as C. brownii (R.Br.) Domin. The plant originally referred to as C. tenulfolia (Burm. f.) Sw. and previously regarded as extending from South-East Asia to the south coast of Australia is here recognized as two different species; the northern species extending from South-East Asia to northern Australia is regarded as C. tenuifolia (Burm. f.) Sw. s. str. and the isolated southern species as C. austrotenuifolia Quirk & Chambers.

The fern genus Cheilanthes in Australia

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The fern genus Cheilanthes in Australia