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Articles 331 - 360 of 709

Full-Text Articles in Botany

Abnormal Cones In Cupressus Sempervirens, Simcha Lev-Yadun Jan 1992

Abnormal Cones In Cupressus Sempervirens, Simcha Lev-Yadun

Aliso: A Journal of Systematic and Floristic Botany

Abnormal cones found in Cupressus sempervirens include bisexual cones and double female and male cones. They are very infrequent, but there are individual trees with a tendency to produce such cones. We suggest that these cones reflect changes in normal hormonal balance.


A New Genus Of Laboulbeniales (Ascomycetes) On A Species Of Phalacrichus (Coleoptera: Dryopoidea: Limnichidae), With A Note On Mirror-Image Asymmetry In The Order, Richard K. Benjamin Jan 1992

A New Genus Of Laboulbeniales (Ascomycetes) On A Species Of Phalacrichus (Coleoptera: Dryopoidea: Limnichidae), With A Note On Mirror-Image Asymmetry In The Order, Richard K. Benjamin

Aliso: A Journal of Systematic and Floristic Botany

A new genus ofLaboulbeniales, with two species, Phalacrichomyces normalis (type) and P. anomalus, is described from Phalacrichus diligens (Coleoptera: Dryopoidea; Limnichidae). Phalacrichomyces is placed in the Stigmatomycetinae of the Laboulbeniaceae where it appears to be most nearly related to Stemmatomyces and Synandromyces among the other 39 genera of the subtribe. The new taxa are characterized and salient features of the structure and development of their ascomata are summarized and illustrated with photographs and line drawings. The ascomata of associated pairs of P. anomalus display a remarkable degree of mirror-image asymmetry. This phenomenon, which appears to be a characteristic, although …


Aggregated Cones In Pinus Halepensis, Simcha Lev-Yadun Jan 1992

Aggregated Cones In Pinus Halepensis, Simcha Lev-Yadun

Aliso: A Journal of Systematic and Floristic Botany

Aggregated female cones were found in 192 Pinus halepensis trees growing in 54 populations in Israel, in habitats of vastly differing ecological conditions. All of these trees also carried normal (1-5 in a whorl) female cones. The number of aggregates per tree varied from one to several dozen. Some of the trees formed aggregates every year, after the first year of aggregate formation, while others formed aggregates only once, or at long intervals. Not all cones in the aggregates reached maturity. The number of cones in an aggregate ranged from six to 62, and they were usually smaller than normal. …


Wood, Bark, And Pith Anatomy Of Old World Species Of Ephedra And Summary For The Genus, Sherwin Carlquist Jan 1992

Wood, Bark, And Pith Anatomy Of Old World Species Of Ephedra And Summary For The Genus, Sherwin Carlquist

Aliso: A Journal of Systematic and Floristic Botany

Quantitative and qualitative data are presented for wood anatomy of 35 collections representing 22 Old World species of Ephedra; the survey of bark and pith anatomy is based on some of these species. Character-state ranges similar to those of the New World species are reported, although more numerous species show vessel absence in latewood. Little diminution in vessel diameter or density occurs in latewood of the eight species that are scandant or sprawling. Helical thickenings or sculpture occur in vessels of about a third of the Old World species, but these thickenings are clearly related to pits, often not …


Genetic Variation In Endemic And Widespread Plant Species, Pamela S. Soltis, Douglas E. Soltis Jan 1991

Genetic Variation In Endemic And Widespread Plant Species, Pamela S. Soltis, Douglas E. Soltis

Aliso: A Journal of Systematic and Floristic Botany

Population genetic theory and methodology were applied to the study of endemic plant species. Levels of genetic variability were compared between endemic species and their more widespread relatives. Six of seven narrowly distributed taxa of Saxifragaceae had significantly reduced genetic diversity relative to species of Saxifragaceae with broader distributions. Two endemic species of the fern Polystichum maintained significantly lower levels of genetic variation than did their more widespread congeners. The implications of these data and those reported for other endemic plant species for designing management strategies are also discussed.


Wood And Stem Anatomy Of Convolvulaceae, Sherwin Carlquist, Michael A. Hanson Jan 1991

Wood And Stem Anatomy Of Convolvulaceae, Sherwin Carlquist, Michael A. Hanson

Aliso: A Journal of Systematic and Floristic Botany

Quantitative and qualitative features of wood and stem anatomy are presented for 44 collections of 16 genera and 35 species ofConvolvulaceae. Markedly furrowed xylem characterizes the genera of tribe Cresseae. Successive cambia occur in 11 of the genera studied. Large patches of axial parenchyma occur in many of these; only in one species was interxylary phloem (formed internally by the cambium) observed in the parenchyma patches. Intraxylary phloem at the periphery of the pith is universal in Convolvulaceae, but newly reported is the fact that in many species, cambial activity adds secondary phloem to the intraxylary phloem strands. These cambia …


The Flora Of The Bonin (Ogasawara) Islands, Mikio Ono Jan 1991

The Flora Of The Bonin (Ogasawara) Islands, Mikio Ono

Aliso: A Journal of Systematic and Floristic Botany

The Bonin (Ogasawara) Islands are an oceanic island group more than 1000 km from the Japanese Archipelago. As in other isolated islands of the Pacific Ocean, their flora is rich in endemic taxa. These endemics are mostly either schizo- or aneuendemics and have chromosome numbers that are either identical to or slightly different from those of their adjacent relatives. Three genera, Callicarpa (Verbenaceae), Crepidiastrum (Compositae), and Pittosporum (Pittosporaceae), are discussed as examples of adaptive radiation within the Bonin Islands. These genera are dispersed by birds, which swallow the seeds and later deposit them in new areas. Like plants with similar …


Steps Toward A Natural System Of The Dicotyledons, Gertrud Dahlgren Jan 1991

Steps Toward A Natural System Of The Dicotyledons, Gertrud Dahlgren

Aliso: A Journal of Systematic and Floristic Botany

Embryological character states are mapped on the diagrams of dicotyledons (G. Dahlgren 1989). The often well-defined pattern of distribution forms a basis for discussing and clarifying phylogenetic relations. It is shown how numerous embryological characters, alone or in combinations, support certain systematic constellations, even if the character states may have arisen independently within a varying number of evolutionary lines. Characters presented are: anther wall formation; tapetum types; cells in pollen grains at dispersal; microsporogenesis; ovule morphology; ovule integuments; endothelium; obturator; parietal tissue; embryo sac formation; antipodal cells; hypostase, embryogeny; polyembryony; endosperm formation; persistence of endosperm; ruminate endosperm; endosperm haustoria; perisperm; …


Distribution And Evolution Of Forms And Types Of Sieve-Element Plastids In The Dicotyledons, Dietmar Behnke Jan 1991

Distribution And Evolution Of Forms And Types Of Sieve-Element Plastids In The Dicotyledons, Dietmar Behnke

Aliso: A Journal of Systematic and Floristic Botany

Sieve-element plastids may contain any combination of protein crystals (c), protein filaments (f), and starch grains (s), or none of these. All structurally distinct combinations (=forms) possible (s, cs, cfs, c, cf, fs, f, o) are recorded among the 2100 dicotyledons investigated so far with the transmission electron microscope (representing 381 of more than 460 families described). The six forms that include c and/or f define the P-type and are found in some 620 species, mainly confined to Magnolianae, Caryophyllanae, Vitanae, and Rutanae (Fabales, Linales, Rhizophorales). A detailed family-by-family analysis and quantitative form-by-form comparison suggests that form-Ss plastids give rise …


Steps Toward A Natural System Of The Dicotyledons, Uwe Jensen Jan 1991

Steps Toward A Natural System Of The Dicotyledons, Uwe Jensen

Aliso: A Journal of Systematic and Floristic Botany

Nucleic acids and proteins provide useful characters for the elucidation of evolutionary relationships. Those protein molecules, e.g., legumins, which are subject to less influence of selection processes, have proven to be most valuable as diagnostic characters in phylogenetic studies. Three systematic investigations conducted using comparative serological legumin analyses are discussed as contributions aiding botanists' understanding of a natural system of classification.


Parallelism, It's Evolutionary Origin And Systematic Significance, K. Kubitzki, P. Von Sengbusch, H. Poppendieck Jan 1991

Parallelism, It's Evolutionary Origin And Systematic Significance, K. Kubitzki, P. Von Sengbusch, H. Poppendieck

Aliso: A Journal of Systematic and Floristic Botany

Parallelism as one of the forms of biological similarity is investigated in the light of recent findings from developmental and molecular biology. From the organismic point of view, functional constraints and evolutionary canalization are well established as causes of parallelism. To these may be added, from the molecular perspective, (a) erratic activations of repressed genes; (b) activations of alternative pathways under the influence ofhomoeotic genes; and (c) horizontal gene transfer, for which a simple mechanism is proposed. The control of gene expression through the action oftransposable elements, reversible to some degree, appears to be an evolutionarily important and frequent phenomenon, …


Germination Patterns In Dicotyledons, H. T. Clifford Jan 1991

Germination Patterns In Dicotyledons, H. T. Clifford

Aliso: A Journal of Systematic and Floristic Botany

Seedlings of about 3500 species of dicotyledons were classified as exhibiting either phanerocotylar or cryptocotylar germination. The percentages of cryptocotylar species in the orders as circumscribed by Dahlgren (J. Linn. Soc., Bot. 80:91-124, 1980) were calculated and grouped into five classes whose distributions were plotted onto a bubble-diagram. The resulting pattern revealed a concentration of cryptocotyly in primitive families thereby supporting the view that within the dicotyledons, cryptocotyly is the primitive germination pattern.


An Essay: Geoedaphics And Island Biogeography For Vascular Plants, A. R. Kruckerberg Jan 1991

An Essay: Geoedaphics And Island Biogeography For Vascular Plants, A. R. Kruckerberg

Aliso: A Journal of Systematic and Floristic Botany

"Islands" of discontinuity in the distribution of plants are common in mainland (continental) regions. Such discontinuities should be amenable to testing the tenets of MacArthur and Wilson's island biogeography theory. Mainland gaps are often the result of discontinuities in various geological attributes-the geoedaphic syndrome of topography, lithology and soils. To discover ifgeoedaphically caused patterns of isolation are congruent with island biogeography theory, the effects of topographic discontinuity on plant distributions are examined first. Then a similar inspection is made of discontinuities in parent materials and soils. Parallels as well as differences are detected, indicating that island biogeography theory may be …


Xchiranthofremontia, An Intergeneric Hybrid Of Chiranthodendron Pentadactylon And Fremontodendron 'Pacific Sunset', James Henrickson Jan 1991

Xchiranthofremontia, An Intergeneric Hybrid Of Chiranthodendron Pentadactylon And Fremontodendron 'Pacific Sunset', James Henrickson

Aliso: A Journal of Systematic and Floristic Botany

x Chiranthofremontia lenzii, an intergeneric hybrid between Chiranthodendron pentadactylon and Fremontodendron 'Pacific Sunset' (Sterculiaceae: Fremontodendreae), was made artifically and is described as a hybrid genus. It shows distinctive intermediacy in floral (particularly androecial) characteristics between the parental taxa.


The Phytogeography And Ecology Of The Coastal Atacama And Peruvian Deserts, P. W. Rundel, M. O. Dillon, B. Palma, H. A. Mooney, S. L. Gulmon, J. R. Ehleringer Jan 1991

The Phytogeography And Ecology Of The Coastal Atacama And Peruvian Deserts, P. W. Rundel, M. O. Dillon, B. Palma, H. A. Mooney, S. L. Gulmon, J. R. Ehleringer

Aliso: A Journal of Systematic and Floristic Botany

The Atacama and Peruvian Deserts form a continuous belt for more than 3500 km along the western escarpment of the Andes from northern Peru to northernmost Chile. These arid environments are due to a climatic regime dominated by the cool, north-flowing Humboldt (Peruvian) Current. Atmospheric conditions influenced by a stable, subtropical anticyclone result in a mild, uniform coastal climate nearly devoid of rain, but with the regular formation of thick stratus clouds below I 000 m during the winter months. Where coastal topography is low and flat, the clouds dissipate inward over broad areas with little biological impact. However, where …


Wood And Bark Anatomy Of Empetraceae; Comments On Paedomorphosis In Woods Of Certain Small Shrubs, Sherwin Carlquist Jan 1990

Wood And Bark Anatomy Of Empetraceae; Comments On Paedomorphosis In Woods Of Certain Small Shrubs, Sherwin Carlquist

Aliso: A Journal of Systematic and Floristic Botany

Wood and bark of 12 collections of Empetraceae representing three genera containing seven species (one with two subspecies) are analyzed with respect to quantitative and qualitative features. Empetraceae have vessels somewhat angular in transection, with scalariform perforation plates and scalariform to opposite vessel-ray pitting. Imperforate tracheary elements are all tracheids. Axial parenchyma is sparse and not subdivided. Rays are characteristically uniseriate and composed of upright cells (older stems have rays with both upright and procumbent cells). These features ally Empetraceae closely to Ericaceae and Epacridaceae. The narrow vessels, quite numerous per mm2 , denote a high degree of wood …


A Monograph Of Sabal (Arecaceae: Coryphoideae), Scott Zona Jan 1990

A Monograph Of Sabal (Arecaceae: Coryphoideae), Scott Zona

Aliso: A Journal of Systematic and Floristic Botany

This monographic study of the New World genus Sabal (Arecaceae: Coryphoideae) recognizes 15 species. In addition to defining species limits and distributions, the study addresses broader questions concerning likely modes of speciation in the group and biogeographic radiation. The systematic treatment incorporates results from extensive field work and studies of leaf anatomy and flavonoid phytochemistry, ecology and biogeography, and morphology. Distribution maps and a key to the taxa are provided. Solutions are offered for the many nomenclatural problems that existed in the genus. A phylogenetic hypothesis, the first for the genus, is proposed. Moreover, phytochemical and anatomical features are examined …


The Genera Of Asteraceae Endemic To Mexico And Adjacent Regions, Jose Luis Villaseñor Jan 1990

The Genera Of Asteraceae Endemic To Mexico And Adjacent Regions, Jose Luis Villaseñor

Aliso: A Journal of Systematic and Floristic Botany

The flora of Mexico includes about 119 endemic or nearly endemic genera of Asteraceae. In this study, the genera are listed and their distribution patterns among the floristic provinces of Mexico analyzed. Results indicate strong affinities of the endemic genera for mountainous and arid or semiarid regions. Since its first appearance in Mexico, the Asteraceae diversified into these kinds of habitats, which were produced mostly by recurrent orogenic and climatic phenomena. The specialized tribes Heliantheae and Eupatorieae are richly represented, a fact that places Mexico as an important secondary center of diversification for the Asteraceae.


The Fascinating History Of The Early Botanical Exploration And Investigations In Southern California, Mildred E. Mathias Jan 1990

The Fascinating History Of The Early Botanical Exploration And Investigations In Southern California, Mildred E. Mathias

Aliso: A Journal of Systematic and Floristic Botany

Information on plant collectors in southern California is scattered through a number of publications, some of them obscure or not well known to botanists. This paper gives a selective account of major collectors from 1793 to 1930. The appendix lists the plant collectors with references to biographical material concerning each. It is hoped that this preliminary account will stimulate further historical studies.


A New Species Of Leucospora (Scrophulariaceae) From The Chihuahuan Desert Of Mexico, James Henrickson Jan 1990

A New Species Of Leucospora (Scrophulariaceae) From The Chihuahuan Desert Of Mexico, James Henrickson

Aliso: A Journal of Systematic and Floristic Botany

A new species, Leucospora coahuilensis, is described that is similar to Schistophragma intermedia in vegetative and floral characteristics, but has seed characteristics of Leucospora showing the value of combining the two genera under the latter genus.


Wood And Bark Anatomy Of Degeneria, Sherwin Carlquist Jan 1990

Wood And Bark Anatomy Of Degeneria, Sherwin Carlquist

Aliso: A Journal of Systematic and Floristic Botany

Wood anatomy of the recently described Degeneria roseiflora differs from that of D. vitiensis by possessing narrower vessels, much thicker-walled vessels and fiber-tracheids, abundant uniseriate rays, and greater numbers of ethereal oil cells in rays. Because both large and smaller wood samples of D. vitiensis were studied, ontogenetic changes in the wood are presented and separated from those features that probably vary with the species. Tyloses and perforated ray cells are newly reported for Degeneria. Anatomy of mature bark of D. roseiflora is described. Wood anatomy of Degeneria is moderately primitive. Although Degeneria is often compared to Himantandraceae and …


New Species Of Scutellaria (Lamiaceae) From The Chihuahuan Desert Region, James Henrickson Jan 1990

New Species Of Scutellaria (Lamiaceae) From The Chihuahuan Desert Region, James Henrickson

Aliso: A Journal of Systematic and Floristic Botany

Three new species of Scutellaria are described from the Chihuahuan Desert Region of Mexico: S. hintoniorum from western Nuevo León, S. wendtii from eastern Chihuahua, and S. carmenensis from northern Coahuila.


Morphological Stasis Abd Molecular Divergence In The Intercontinental Disjunct Genus Datisca (Datiscaceae), Aaron Liston, Loren H. Rieseberg, Thomas S. Elias Jan 1990

Morphological Stasis Abd Molecular Divergence In The Intercontinental Disjunct Genus Datisca (Datiscaceae), Aaron Liston, Loren H. Rieseberg, Thomas S. Elias

Aliso: A Journal of Systematic and Floristic Botany

The genus Datisca comprises two species and has an intercontinentally disjunct distribution: D. cannabina is native to southwest and central Asia, whereas D. glomerata is distributed from northern California to northern Baja California. In 1975, Axelrod proposed a geohistorical scenario to account for such "Madrean-Tethyan links," suggesting that these disjunctions resulted from migration across the mid-Atlantic from the Paleogene up to the Neogene, approximately 23 to 65 m.y.a. The two species are quite similar in most phenotypic traits which have been studied to date. The major difference between the two involves their breeding system: D. cannabina is dioecious while D. …


Relationships Among Wood Variables In Two Species Of Ring-Porous Trees, D. W. Woodcock Jan 1990

Relationships Among Wood Variables In Two Species Of Ring-Porous Trees, D. W. Woodcock

Aliso: A Journal of Systematic and Floristic Botany

One way of assessing the functional significance of wood-anatomical variables is by examining the relationships among these variables. This paper presents results of factor analysis of wood variables in two species of ring-porous trees (Quercus rubra and Fraxinus americana). Factor analysis of vessel diameter and density, conductive area, and conductivity in the early- and latewood plus width of the early- and Iatewood increment reveals from three to four independent sources of variance. Generally, these can be characterized as diameter-related factors in the early- and latewood, tentatively related to water conduction, and a factor identified with width of the …


Steps Toward The Natural System Of The Dicotyledons, William C. Dickison Jan 1990

Steps Toward The Natural System Of The Dicotyledons, William C. Dickison

Aliso: A Journal of Systematic and Floristic Botany

The value of vegetative anatomy in phylogenetic analysis is documented. Examples of the use of vegetative anatomy at different taxonomic levels show the continuing role of the anatomical method in building a more natural system of classification of the dicotyledons. The importance of correlating wood and leaf anatomical features with ecological and floristic preferences of taxa is emphasized. Caution is required in basing phylogenetic interpretations upon similarities and differences in xylem structure. The transition from scalariform to simple perforation plates is the only aspect of vessel element evolution that is not potentially reversible and all phylogenetic analyses must reflect this …


A New Scandent Species Of Bidens (Asteraceae) From The Balisas River Basin, Mexico, Jose Luis Villaseñor Jan 1990

A New Scandent Species Of Bidens (Asteraceae) From The Balisas River Basin, Mexico, Jose Luis Villaseñor

Aliso: A Journal of Systematic and Floristic Botany

Bidens esmartinezii from the Balsas River Basin, Michoacan and Guerrero, Mexico, differs from B. reptans var. urbanii and B. squarrosa, the only other climbing species occurring in the area, by its entire, mostly linear leaf lobes and its larger, brown achenes.


Monardella Stebbinsii (Lamiaceae), A New Serpentine Endemic Species From The Northern Sierra Nevada, Plumas County, California, Clare B. Hardham, Jim A. Bartel Jan 1990

Monardella Stebbinsii (Lamiaceae), A New Serpentine Endemic Species From The Northern Sierra Nevada, Plumas County, California, Clare B. Hardham, Jim A. Bartel

Aliso: A Journal of Systematic and Floristic Botany

Monardella stebbinsii (Lamiaceae ), a new species from the northern Sierra Nevada of Plumas County, California, is described and illustrated. Characterized by ovate leaves, multiple verticillasters per infiorascence, a matlike habit, reddish papery bracts, and purplish-red leaves with a soft white pubescence, the species is not closely related to any other species of the genus. The new species is apparently restricted to the central portion of a serpentine outcrop located north and east of the confluence of the North Fork of the Feather River and its East Branch.


Dudleya Cymosa Subsp. Costafolia (Crassulaceae), A New Subspecies From The Southern Sierra Nevada, Tulare County, California, Jim A. Bartel, James R. Shevock Jan 1990

Dudleya Cymosa Subsp. Costafolia (Crassulaceae), A New Subspecies From The Southern Sierra Nevada, Tulare County, California, Jim A. Bartel, James R. Shevock

Aliso: A Journal of Systematic and Floristic Botany

Dudleya cymosa subsp. costafolia, a new subspecies from the southern Sierra Nevada, Tulare County, California, is described and illustrated. Along with bright yellow flowers, the cespitose plant produces numerous, small rosettes with rib-shaped linear to linear-oblanceolate leaves, which are unique to the subspecies. The authors have searched numerous other rock outcrops, especially limestone, in the general area for additional plants with no success. Dudleya cymosa subsp. costafolia evidently is restricted to a solitary limestone outcrop north of the South Fork of the Middle Fork of the Tule River.


Stem And Leaf Anatomy Of The Alseuosmiaceae, William C. Dickison Jan 1990

Stem And Leaf Anatomy Of The Alseuosmiaceae, William C. Dickison

Aliso: A Journal of Systematic and Floristic Botany

The stem and leaf anatomy of five species representing all three genera of the small Southwest Pacific dicotyledonous family, Alseuosmiaceae, were studied. Salient anatomical features common to all genera include: a trilacunar, three-trace leaf-node structure in which petioles are supplied with three separate vascular bundles; rosoid teeth bearing hydathodes; anomocytic stomata; unicellular, bicellular, and multicellular, unbranched, living trichomes; a superficial origin of periderm; leafmesophyll composed of a uniseriate palisade region and a loosely constructed spongy zone; and the presence of a stem and foliar endodermis. Sclerenchyma occurs in stem tissues of species belonging to all three genera and Crispiloba disperma …


Wood And Bark Anatomy Of The New World Species Of Ephedra, Sherwin Carlquist Jan 1990

Wood And Bark Anatomy Of The New World Species Of Ephedra, Sherwin Carlquist

Aliso: A Journal of Systematic and Floristic Botany

Quantitative and qualitative data are presented for wood of 42 collections of 23 species of Ephedra from North and South America; data on bark anatomy are offered for most of these. For five collections, root as well as stem wood is analyzed, and for two collections, anatomy of horizontal underground stems is compared to that of upright stems. Vessel diameter, vessel element length, fiber-tracheid length, and tracheid length increase with age. Vessels and tracheids bear helical thickenings in 10 North American species (first report); thickenings are absent in Mexican and South American species. Mean total area of perforations per mm …