@article {316, title = {Origins and nature of vessels in monocotyledons. 2. Juncaginaceae and Scheuchzeriaceae}, journal = {Nordic Journal of Botany}, volume = {17}, number = {4}, year = {1997}, month = {23-1-1997}, pages = {397-401}, abstract = {SEM studies of roots and rhizomes of Triglochin (one species) and Maundia (monotypic) of Juncaginaceae and the sole species of Scheuchzeriaceae, Scheuchzeria palustris, reveals that vessels are present not only in roots, as previously reported, but also in rhizomes. The perforations contain pit membranes with pores of various sizes. Striate pit membranes, like those previously seen in Acorus, occur on pit remnants in perforations and on pit membranes of lateral walls in all genera studied. Grooves interconnecting pit apertures are illustrated for root tracheary elements of Triglochin; this is believed to be a first report of this feature for monocotyledons. The tracheary elements of Juncaginaceae and Scheuchzeriaceae are similar in their thick walls and narrow slitlike pits, lending support to the close relationship between the two families often claimed.}, author = {Schneider, Edward L. and Carlquist, Sherwin} } @article {282, title = { Inselberg vegetation and the biodiversity of granite outcrops}, journal = {Journal of the Royal Society of Western AustraliaJournal of the Royal Society of Western Australia}, volume = {80}, year = {1997}, pages = {193-199}, abstract = {Granite inselbergs occur as mostly dome-shaped rock outcrops in all climatic and vegetational zones of the tropics. Consisting of Precambrian rocks, they form ancient and stable landscape elements. Due to harsh edaphic and microclimatic conditions, the vegetation of inselbergs differs markedly from those of the surroundings. Well defined inselberg habitats (e.g. cryptogamic crusts, rock pools, monocotyledonous mats, ephemeral flush vegetation) can be distinguished based on physiognomy. Plant diversity of inselbergs is influenced by both deterministic processes and stochastic environmental disturbances. The latter promote higher species richness due to the prevention of competitive exclusion. Considerable regional differences in floristic composition, life forms and species diversity exist concerning both the vegetation of whole inselbergs as well as those of individual habitats.}, keywords = {inselbergs, Inselberge, granite outcrops, vegetation, flora, tropics}, author = {Porembski, Stefan and Seine, R. and Barthlott, Wilhelm} } @article {203, title = {Phylogenetic Studies in Alismatidae, II: Evolution of Marine Angiosperms (Seagrasses) and Hydrophily}, journal = {Systematic BotanySystematic Botany}, volume = {22}, number = {3}, year = {1997}, pages = {443-463}, author = {Les, Donald H. and Cleland, Maryke A.} } @article {161, title = {Plants of Western Australian granite outcrops}, journal = {Journal of the Royal Society of Western Australia}, volume = {80}, year = {1997}, note = {several Triglochin species mentioned in Appendix (species list):Triglochin aff. minutissimumT. calcitrapum subsp. incurvumT. centrocarpumT. minutissimum}, pages = {141-158}, abstract = {

Outcropping granite rocks in Western Australia span a considerable climatic range, from the mediterranean south-west to inland desert and northern arid subtropics and tropics. At least 1320, and possibly 2000, plant taxa occur on Western Australian granite outcrops. Outcrop plant life is most diverse in the South West Botanical Province, with individual outcrops having up to 200 species, including many endemics not found in surrounding habitats. Species richness and local endemism declines with increasing aridity, to the point where Kimberley and Pilbara outcrops show little discontinuity in species from the surrounding landscape matrix. Outcrops are dominated by woody and herbaceous perennials, especially of the Myrtaceae, Orchidaceae, and Mimosaceae, and have an unusually rich diversity of annuals (Asteraceae, Stylidiaceae, Poaceae, Amaranthaceae etc.) compared with the flora as a whole. An unusual life form is found in resurrection plants capable of extreme desiccation and rehydration (e.g. Borya, Cheilanthes). Among woody perennials, bird pollination is frequent, and some outcrops harbour a high proportion of obligate seeder species due to the refuge from fire provided by bare rock barriers. The diversity of microhabitats and soil moisture regimes on outcrops has enabled the persistence of species beyond their main range in the face of climatic fluctuations. It has also facilitated the evolution of many endemics in the south-west. Major threatening processes facing outcrop plant communities include weed invasion, grazing by stock and feral animals, too-frequent fire, clearing, loss of shrub layer, salinity, and dieback. Conservation of these rich rare habitats needs the support of local communities.

}, keywords = {annuals, flora, granite outcrops, Triglochin, vegetation, Western Australia}, author = {Hopper, Stephen D. and Brown, A.P. and Marchant, N.G.} }