In a previous paper (1961) the authors described in detail twelve species of woods, representing nine genera {Acer, Diospyros, Quercus, Liquidambar, Carya, Albizzia, Gleditsia, Platanus, and Ulmus) from the Columbia Basalts of the area of Vantage, Washington.The silicified woods described represent a small fraction of an extensive collection made in 1954 by Mr. Jay O'Leary, while he was a student in Harvard College.The present investigation is a continuation of the systematic study of this collection.In this paper we are concerned with the identification and description of six additional species representing four genera not recorded in the first paper.It is probable that the total number of genera preserved in the basalts of the Vantage area may be in excess of 30 of which more than two-thirds are genera of dicotyledonous trees.In a previous communication, Beck (1945) listed 2 7 genera determinable in the Vantage and nearby stratigraphically equivalent areas.It is of interest to note that only slightly more than one-third of these genera currently exist in the flora of the general region today (Wolfe and Barghoorn, 1960).Although the age of the flora with which our study is concerned is generallv^egarded to be Upper Miocene, the high percentage of genera represented in this fossil flora but now exotic to the region would tend to indicate a lower stratigraphic position in the Miocene sequence (Barghoorn, 1951; Wolfe and Barghoorn, 1960).This reconsideration of the age of the Vantage (Russell Forests) flora is also supported by comparison of generic composition with that of the Latah flora, a large flora the composition of which is known from leaf impressions rather than silicifled woods.The Latah flora is comprised of genera of which only slightly more than one-third are extant in the geographic region today.Statistical examination of thirteen floras of the western United States generally regarded as Upper or Late Miocene, on the other hand, indicates that between 50 to 67 per cent of their genera are yet in the geographic region of the fossil floras.FAGACEAE 1. Q (Figs. 16-19)Growth rings: Distinct; wood ring-porous.Transition between early and late wood abrupt.(Fig. 19).Vessels: Large vessels in the early wood (Fig. 19), 192-416 /^ in tangential diameter (mean diameter 269 /x), solitary, forming a conspicuous band 1 or 2 pores in width, thin walled, vessels round to oval, occasionally
Menonvillea DC. is a genus of thirty species distributed primarily in the drier portions of northern and central Chile and the adjacent provinces of Argentina.The range of the genus extends southward into Patagonia, and of the eight species that grow there, only M. nordenskjoeldii (Dusen) Rollins reaches as far south as Prov.Santa Cruz, Argentina, and Region Magallanes y Antartica Chilena (Boelcke & Romanczuk, 1984).Seventeen species are restricted to Chile and eight to Argentina, while five grow in both countries (Rollins, 1955).Most species of MenonviUea are perennials with either an unbranched caudex or a deep, fleshy or woody, much-branched, rhizomelike caudex.About eight species are annuals, and two <>th< rs 1/ linearis D( and M. pituiaiifida Barneoud, are annuals that sometimes perennate under favorable conditions.From the underground caudex.all of the perennial species annually produce new herbaceous stems that bear flowers and fruits and then die at the end of the
Scanning-electron-microscope observations and stomatal-density counts indicate that two populations of Ecuadorian Begonia parviflora have very different surface epidermal characteristics
Lyonia truncata var. proctorii is a member of Lyonia sect. Lyonia and as such is characterized by an indumentum of unicellular hairs and multicellular, ferrugineous, biseriate-stalked, peltate scales. It is described and illustrated from specimens collected in the Sierra Bermeja of southwestern Puerto Rico
Linnaeus's ideas on the composition of the various parts of the plant and the generation of plant form by the interactions of these tissues both with each other and with the sap of the plant are outlined. Linnaeus used the analogy he drew between the vegetative plant and the larva of an insect to justify his emphasis on parts of the fructification in the classification of genera; as with insects, he used the adult, rather than the larva, in classification
The purpose of this paper is to report the nodal structure of the unusual unistipulate leaves of the monotypic genus Mytilaria Lecomte. The nodes display a vascular pattern not previously known in the Hamamelidaceae but of apparent taxonomic significance
Thirty species of Selaginella are currently known from Guizhou Province in south-central ( Inn i I | i ies is given Following the key are notes on species that ao newly disco\ red in tin province, previously unde-Selaginella Beauv. in China has not been studied thoroughly since Alston enumerated the < 'lunese species in !()34.In some provinces or regions, however, the vascular llt.i.i including Sc/nyj/icl/a has been treated; currently about 50 species of this genus are estimated to occur in Chine, with 30 species known from Guizhou (Kweichow) Pr< inci nth iuth-( i il part of the country. Key to theSpecies of Selaginella in Guizhou 1. Main stems erect ubereei o candent oi pi mi , with densely tufted stems; plants usually rooting at base or in lower parts.2. Stems densely tufted or branched from base; plants xerophytic.3 Stt ne, n d branched from basi lateral and medi m leaves directed forward. 1 .S. sanguinolenta.3. Stems brown, densely tufted; only median leaves directed forward • S /'/'Am, /,, 2. Stems not branched near base, or if branched from base plants not xerophytic.4. Plants at most 6 cm high: mam stems more or less zigzag 3. S. kouycheensis.4. Plants much larger; main stems not zigzag.5. Plants over 1 m long ,< audi m ,}.s. lic/fcn. 5. Plants generally less than 60 cm tall, not scandent.6. Branches pubescent.rinkled when dry; northern and r
