JOURNAL OF THE ARNOLD ARBORETUMMARTICORENIA: A NEW GENUS OF MUTISIEAE (COMPOSITAE) JORGE VICTOR CRISCI IN THE COURSE OF A revisionary study of the genus Leuceria Lagasca(Compositae, tribe Mutisieae, subtribe Nassauviinae), Leuceria foliosa, aspecies described by the Chilean botanist R. Philippi in 1856, seemed tobe out of place. The species grows in the Andean region of central Chile.A careful study of this species and of all the genera of this subtribe con-vinces me that Leuceria foliosa should be recognized as a new genus. A description of the new genus and its one species, with illustrations,pollen analysis, chromosome number, and discussion of the generic relation-ships of the new taxon is presented in this paper. The abbreviations forherbaria listed in the citations of specimens are taken from the fifthedition of the Index Herbariorum (Lanjouw & Stafleu, 1964). MATERIAL AND METHODS Some pollen grains were acetolysed according to the method outlinedby Erdtman (1960); other pollen grains were placed in 95 per centethanol stained with basic fuchsin and mounted in glycerine jelly. ForScanning Electron Microscopy (SEM) the acetolysed pollen grains wereused. After acetolysis the pollen samples were washed several times inglass-distilled water to remove traces of acids. Each sample was dispersedin a drop of distilled water and placed on a specimen holder. The sampleswere then air dried, coated with 50 A to 100 A carbon and about 200A to 300 A gold-palladium alloy for conductivity. Finally the specimenswere photographed using a high resolution SEM, AMR model 900. FIG-URES 1-4. To obtain the chromosome number, flower buds were collected fromplants growing in their native habitat. Buds were killed and fixed inethanol and glacial acetic acid (3:1), transferred to 70 per cent ethanolafter 24 hours, and refrigerated. Anthers were squashed in aceto-carmine.Marticorenia Crisci, gen. nov. Capitulum multiflorum, homogamum; floreshermaphroditi. Involucrum hemisphaericum; bracteae lineari-lanceolatae,biseriatae. Receptaculum vix concavum, paleaceum; paleae rigentes vixamplexiflorae. Flores albo-violacei, bilabiati, labio interiore bipartito lobisrevolutis, labio exteriore latiore ligulato tridentato. Antherae glabrae,basi longe sagittatae. Stylus bifidus; rami semiteretes, apice truncati penicil-latisque, divergentes non revoluti. Achaenia cylindrata, papilloso-puberula.Pappus uniseriatus, pilis plumosis albis. Frutex dense pilosus; foliis alter-nis, sessilibus, ovatis lobatisque, basi cordatis et semiamplexicaulibus.Capitula pedunculata laxe cymosa. Pedicellus unibracteatus. SPECIESTYPICA: Marticorenia foliosa (Philippi) Crisci.[VOL. 55
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