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No. 282 February 20, 2002
aceska at victoria.tc.ca Victoria, B.C.
Dr. A. Ceska, P.O.Box 8546, Victoria, B.C. Canada V8W 3S2
This issue of BEN is dedicated to
those small specks that botanists tend to overlook
PHYTOLITH LITERATURE REVIEW
From: Terry B. Ball [tbball at reled.byu.edu]
Attached is a brief intro to Phytoliths taken form the following
Ball, T.B., and J. D. Brotherson. 1992. The effect of varying
environmental conditions on phytolith morphology in two
species of grass (_Bouteloua curtipendula_ and _Panicum
virgatum_). Scanning Electron Microscopy 6:1163-1182.
Other more recent publications in which I discuss similar topics
Ball, T.B., J.D. Brotherson, and J.S. Gardner. 1996. Identifying
phytoliths produced by the inflorescence bracts of three
species of wheat (_Triticum monoccocum_ L., _T. dicoccon_
Schrank., and _T. aestivum_ L.) using computer-assisted image
and statistical analyses. _Journal of Archaeological Science_
Ball, T.B., J.D. Brotherson, and J.S. Gardner. 1993. A typologic
and morphometric study of phytoliths from einkorn wheat
(_Triticum monococcum_ L.). _Canadian Journal of Botany_
I also have a phytolith webpage at
[this link did not work on 2002/02/20]
Monosilicic acid in the soil, created from the weathering of
rocks and the dissolution of biologically deposited SiO2, is
taken up by plant roots. Following uptake the acid is
transported to various plant organs, where, in many taxa, some
of it polymerizes to form solid silica deposits at specific
intracellular and extracellular locations (Jones and Handreck,
1967; Raven, 1983; Sangster, 1970). These solid deposits of
SiO2, as well as deposits containing calcium compounds, have
been given the name "phytolith", literally meaning "plant-
rocks." Many plants produce phytoliths with morphological
characteristics that appear unique to a given taxon, a
phenomenon giving them taxonomic significance.
There has been considerable interest in phytolith research.
Phytolith formation and deposition in various cereal grasses has
been well documented (Blackman, 1968, 1969; Blackman and Parry,
1968; Hayward and Parry, 1973; Hodson and Sangster, 1989; Hutton
and Norrish, 1974; Jones and Handreck, 1965; Kaufman et al.,
1972; Soni and Parry, 1973). The role of phytoliths in plant
resistance to disease and insects has been investigated (De
Silva and Hillis, 1980; Djamin and Pathak, 1967; Hanifa et al.,
1974; Jones and Handreck, 1967; Kunoh and Ishizaki, 1975; Lan-
ning, 1966), as well as the detrimental effects phytoliths have
on herbivores and humans (Baker, 1961, Baker et al., 1959;
Bezeau et al., 1966; Forman and Sauer, 1962; Harbers et al.,
1981; O'Neill et al., 1982; Parry and Hodson, 1982; Bhatt et
al., 1984). Phytolith research has proved highly valuable to
archaeobotanists. Because phytoliths are siliceous, when a plant
dies, even if it is burned, buried, or ingested, its phytoliths
persist and maintain their morphological integrity, becoming a
microfossil of that plant. Microfossil phytoliths have been
collected by archaeobotanists from such diverse environments as
paleosols exposed by erosion or excavation (Piperno, 1983,
1988), ceramics and bricks made from clay upon which vegetation
once grew, or to which plant fibers were added (Rands and Bar-
gielski, paper presented at the 1986 meeting of the Society for
American Archaeology) tooth tartar and coproliths of herbivores
(Bryant, 1974; Armitage, 1975), and the surface of stone tools
used to process plants and/or plant parts (Kamminga, 1979;
Once collected and analyzed, microfossil phytoliths can provide
researchers with significant information and insights. Microfos-
sil phytoliths have been used for the reconstruction of paleoen-
vironments (Fisher et al., 1987; Lewis, 1981; Robinson, 1979;
Rovner, 1971; Twiss, 1987), as indicators of ancient industrial
and agricultural practices (Liebowitz and Folk, 1980; Piperno,
1984; Rosen, 1992; Rosen, 1999), and for tracing the origins and
developments of cultigens (Piperno, 1988). Rovner (1983) in
reviewing the value and advances of phytolith research, sug-
gested that it has the potential to become a second palynology.
Pearsall (1989) and Piperno (1988) point out that phytolith
analysis is especially valuable to archaeobotanists at sites of
study were other plant remains are absent. They further indicate
that when phytoliths are used in conjunction with other plant
remains, they add precision and support for any interpretations
Anderson, P.C. 1980. A testimony of prehistoric tasks: diagnos-
tic residues on stone tool working edges. _World archaeology_
Armitage, P.L. 1975. The extraction and identification of opal
phytoliths from the teeth of ungulates. _Journal of Ar-
chaeological Science_ 2: 187-197.
Baker, G. 1961. _Opal phytoliths and adventitious mineral par-
ticles in wheat dust._ Commonwealth Scientific and Industrial
Research Organization, Australia; Mineralgraphic Investiga-
tions Technical Paper No. 4, 3-l2.
Baker, G., L.H.P. Jones, & I.D. Wardrop. 1959. The cause of wear
in sheep's teeth. _Nature_ 184: 1583-4.
Bezeau L.M., A. Johnson, & S. Smoliak. 1966. Silica and protein
content of mixed prairie and fescue grassland vegetation and
its relationship to the incidence of silica urolithiasis.
_Canadian Journal of Plant Science_ 46: 625-631.
Bhatt, T.S., M.M. Coombs, & C.H. O'Neill. 1984. Biogenic silica
fibre promotes carcinogenesis in mouse skin. _International
Journal of Cancer_ 34: 519-528.
Blackman, E. 1968. The pattern and sequence of opaline silica
deposition in rye (_Secale cereale_ L.). _Annals of Botany_
Blackman, E. 1969. Observations on the development of the silica
cells of the leaf sheath of wheat (_Triticum aestivum_).
_Canadian Journal of Botany_ 47: 827-838.
Blackman, E. 1971. Opaline silica bodies in the range grasses of
southern Alberta. _Canadian Journal of Botany_ 49: 769-81.
Blackman, E. & D.W. Parry. 1968. Opaline silica deposition in
rye (_Secale cereale_ L.). _Annals of Botany_ 32: 199-206.
Bozarth, S.R. 1987. Diagnostic opal phytoliths from rinds of
selected _Cucurbita_ species. _American Antiquity_ 52: 607-
Brown, D. 1984. Prospects and limits of a phytolith key for
grasses in the central United States. _Journal of Ar-
chaeological Science_ 11: 221-243.
Bryant, V.M., Jr. 1974. The role of coprolith analysis in Ar-
chaeology. _Texas Archaeological Society Bulletin_ 45: 1-28.
De Silva, D.& W.E. Hillis. 1980. The contribution of silica to
the resistance of wood to marine borers. _Holzforschung_ 34:
Dayanandan, P., P.B. Kaufman, & C.I. Franklin. 1983. Detection
of silica in plants. _American Journal of Botany_ 70: 1079-
Djamin, A. & M.D. Pathak. 1967. Role of silica in resistance to
asiatic rice borer, _Chilo suppressalis_ (Walker), in rice
varieties. _Journal of Economic Entomology_ 60: 347-351.
Fisher, R.F., M.J. Jenkins, & W.F. Fisher. 1987. Fire and the
prairie-forest mosaic of Devils Tower National Monument. _The
American Midland Naturalist_ 117: 250-257.
Forman, S.A. & F. Sauer. 1962. Some changes in the urine of
sheep fed a hay high in silica. _Canadian Journal of Animal
Science_ 42: 9-17.
Gould, F.W. & R.B. Shaw. 1983. _Grass Sytematics_, 2nd edition,
Texas A & M University Press, College Station 226.
Hanifa, A.M., T.R. Subramaniam, & B.W.X. Ponnaiya. 1974. Role of
silica in resistance to the leaf roller, _Cnaphalocrocis
medinalis_ Guenee, in rice. _Indian Journal of Experimental
Biology_ 12: 463-465.
Harbers, L.H., R.J. Raiten, & G.M. Paulsen. 1981. The role of
plant epidermal silica as a structural inhibitor of rumen
microbial digestion in steers. _Nutrition Reports Interna-
tional_ 24: 1057-1066.
Hayward, D.M. & D.W. Parry. 1973. Electron-probe microanalysis
studies of silica deposition in barley (_Hordeum sativum_
L.). _Annals of Botany_ 37: 579-591.
Hodson, M.J. & A.G. Sangster. 1989. Silica deposition in the
inflorescence bracts of wheat (_Triticum aestivum_). II. X-
ray microanalysis and backscattered electron imaging.
_Canadian Journal of Botany_ 67: 281-287.
Hutton, J.T. & K. Norrish. 1974. Silicon content of wheat husks
in relation to water transpired. _Australian Journal of
Agricultural Research_ 25: 203-212.
Jones, L.H.P. & K.A. Handreck. 1965. Studies of Silica in the
oat plant. III. Uptake of silica from soils by the plant.
_Plant and Soil_ 23: 79-96.
Jones, L.H.P. & K.A. Handreck. 1967. Silica in soils plants and
animals. _Advances in Agronomy_ 19: 107-149.
Kamminga, J. 1979. The nature of use-polish and abrasive smooth-
ing on stone tools. Pp. 143-157 in : Hayden, B. (ed.) _Lithic
Use-wear Analysis_, Academic Press, New York.
Kaufman, P.B., S.L. Soni, J.D. Lacroix, J.J. Rosen, & W.C.
Bigelow. 1972. Electron-probe microanalysis of silicon in the
epidermis of rice (_Oryza sativa_ L.) internodes. _Planta_
Kunoh, H. & H. Ishizaki. 1975. Silicon levels near penetration
sites of fungi on wheat, barley, cucumber, and morning glory
leaves. _Physiological Plant Pathology_ 5: 283-287.
Lanning, F.C. 1966. Barley silica: relation of silicon in barley
to disease, cold, and pest resistance. _Journal of Agricul-
ture and Food Chemistry_ 14: 636-638.
Lewis, R.O. 1981. Use of opal phytoliths in paleoenvironmental
reconstruction. _Journal of Ethnobiology_ 1: 175-181.
Liebowitz, H. & R.L. Folk. 1980. Archaeological geology of Tel
Yin'am, Galilee, Israel. _Journal of Field Archaeology_ 7:
Mulholland, S.C. & G.R. Rapp, Jr. 1989. Characterization of
grass phytoliths for archaeological analysis. _Materials
Research Bulletin_ 14: 36-39.
Ollendorf A.L., S.C. Mulholland, & G. Rapp, Jr. 1988. Phytolith
analysis as a means of plant identification: _Arundo donax_
and _Phragmites communis_. _Annals of Botany_ 61: 209-214.
O'Neill, C.H., Q. Pan, G. Clarke, F.S. Liu, G. Hodges, M. Ge, P.
Jordon, Y.M. Chang, R. Newman, & & E. Toulson. 1982. Silica
fragments from millet bran in mucosa surrounding oesophageal
tumors in patients in northern China. _The Lancet_ 15(May 29,
Parry, D.W. & F. Smithson. 1964. Types of opaline silica deposi-
tions in the leaves of British grasses. _Annals of Botany,
N.S._ 28(109): 169-85.
Parry, D.W. & F. Smithson. 1966. Opaline silica in the in-
floresences of some British grasses and cereals. _Annals of
Botany, N.S._ 30(119): 525-38.
Parry, D.W. & M.J. Hodson. 1982. Silica distribution in the
caryopsis and inflorescence bracts of foxtail millet
(_Setaria italica_) and its possible significance in car-
cinogenesis. _Annals of Botan, N.S._ 49: 531-540.
Pearsall, D.M. 1978. Phytolith analysis of archaeological soils:
evidence for maize cultivation in formative Equador.
_Science_ 199: 177-178.
Pearsall, D.M. 1989. _Paleoethnobotany: A Handbook of
Procedures._ Academic Press, San Diego.
Piperno, D.R. 1983. _The application of phytolith analysis to
the reconstruction of plant subsistence and environments in
prehistoric Panama._ Ph.D. Dissertation, Temple University.
Piperno, D.R. 1984. A comparison and differentiation of
phytoliths from maize (_Zea mays_ L.) and wild grasses: Use
of morphological criteria. _American Antiquity_ 49: 361-383.
Piperno, D.R. 1985. Phytolith analysis and tropical paleo-
ecology: production and taxonomic significance of siliceous
forms in New World plant domesticates and wild species.
_Review of Paleobotany and Palynology_ 45: 185-228.
Piperno, D.R. 1988. _Phytoliths analysis: An archaeological and
geological perspective._ Academic Press, San Diego.
Rapp, G.R., Jr. 1986. Morphological classification of
phytoliths, Pp. 33-35 in: Rovner, I. (ed.) _Plant opal
phytolith analysis in archaeology and paleoecology, Proceed-
ings of the 1984 Phytolith Research Workshop, North Carolina
State University, Raleigh, Occasional Papers No. 1 Raleigh.
Raven, J.A. 1983. The transport and function of silicon in
plants. _Biological Reviews of the Cambridge Philosophical
Society_ 58: 179-207.
Robinson, R.L. 1979. Biosilica analysis: paleoenvironmental
reconstruction of 41 LL 254. Appendix III in: Assad, C. &
D.R. Porter. _An Intensive Archaeological Survey of Enchanted
Rock State Natural Area._ Center for Archaeological Research
Survey Report 84, San Antonio.
Rosen, A.M. 1992. Preliminary identification of silica skeletons
from near eastern archaeological sites: an anatomical ap-
proach. Pp. 129-147 in: Mulholland S. & G. Rapp, Jr. (eds.)
_Phytolith systematics: Emerging issues._, Plenum Press, New
Rosen, A, 1999. Phytoliths as indicators of prehistoric irriga-
tion farming, Pp. 193-198 in: Anderson, P.C. (ed.) _Prehis-
tory of Agriculture: New Experimental and Ethnographic
Approaches._ 193-198. UCLA,Institute of Archaeology, Los
Rovner, I. 1971. Potential of opal phytoliths for use in
paleoecological reconstruction. _Quaternary Research_ 1: 345-
Rovner, I. 1983. Plant opal phytolith analysis: major advances
in archaeobotanical esearch, Pp. 225-266 in: Schiffer, M.
(ed.) _Advances in Archaeological Method and Theory (6)_
Academic Press, New York.
Rovner, I. & J.C. Russ. 1992. Darwin and design in phytolith
sytematics: Morphometric methods for mitigating redundancy.
Pp. 253-276 in: Mulholland S. & G. Rapp, Jr. (eds.)
_Phytolith Systematics: Emerging issues._ Plenum Press, New
York and London.
Russ, J.C. & I. Rovner. 1987. Stereological verification of Zea
phytolith taxonomy. _Phytolitharien Newsletter_ 4: 10-18.
Sangster, A.G. 1970. Intracellular silica deposition in immature
leaves in three species of the Gramineae. _Annals of Botany_
Soni, S.L. & D.W. Parry. 1973. Electron probe microanalysis of
silicon deposition in the inflorescence bracts of the rice
plant. (_Oryza sativa_). _American Journal of Botany_ 60:
Twiss, P.C. 1987. Grass-opal phytoliths as climatic indicators
of the Great Plains Pleistocene, Pp. 179-188 in: Johnson,
W.C. (ed.) _Quaternary Environments of Kansas._ Kansas
Geological Survey Guidebook Series 5. 179-188.
Twiss, P.C., E. Suess, & R.M. Smith. 1969. Morphological class-
ification of grass phytoliths. _Soil Science Society of
America Proceedings_ 33: 109-115.
PHYTOLITH STUDIES IN WESTERN NORTH AMERICA
From: Mikhail Blinnikov [mblinnikov at stcloudstate.edu]
Virtues and values of phytolith studies
Phytoliths are silicified replicas of plant cells, which are
morphologically distinct, abundant, and durable in soils, loess,
cave deposits and other dry environments (Piperno, 1988). Opal
phytoliths have been described from many North American plants,
mostly grasses and trees, including those in the Pacific
Northwest (Norgren, 1973; Klein and Geis, 1978; Brown, 1984;
Mulholland, 1989). The phytoliths' main strength is their
durability under a wide range of depositional conditions and
possibility of identifying plant communities, and sometimes
individual taxa, based on matching paleoassemblages with modern
analogues. In addition to individual shape counts, phytolith
concentrations can be used to infer presence/absence of forested
vegetation, as well as to indicate presence of buried A soil
horizons (Verma and Rust, 1969; Wilding and Drees, 1971). Most
work on phytoliths in North America has focused on archaeologi-
cal applications, it is only recently that we began to ap-
preciate their large potential for paleoenvironmental
Research approach (extraction, analysis, etc.)
The extraction of phytoliths from plant tissue is done by dry
oxidation for a few hours in a muffle furnace at 550 ?C, by wet
oxidation with a heated strong acid, or combined wet and dry
oxidation (Pearsall, 2001). In my work I use modified method of
Piperno (1988, modified in Blinnikov, 1999) for extraction of
phytoliths from soils. Phytoliths can be quantitatively ex-
tracted from the silt fraction of soil or loess (5-100 microns,
20-50 g of soil per sample). After soil fractionation and
removal of clay and sand, the organics are removed by a con-
centrated (70% or more) nitric acid with a pinch of potassium
perchlorate added per 50 ml test tube. Carbonates are removed by
mild hydrochloric acid. Opal fraction (phytoliths) is be
separated from quartz and other heavier minerals using flotation
in sodium polytungstate or zinc bromide solution (specific
gravity of 2.3 g/cm3). Concentration of phytoliths is calculated
based on the ratio of the total dry weight of the opal residue
to the total dry weight of the initial sample. Information about
vegetation composition can be then obtained based on identifica-
tion of individual phytolith shapes from fossil samples under a
light microscope and matching the paleoassemblages against a
reference collection from modern plants and soils by using
squared chord distance approach and detrended correspondence
analysis, or similar multivariate techniques.
Phytoliths in western North America
While there exists a considerable bibliography on phytolith
research worldwide (Runge, 1998), little work has been reported
from western North America. Some early works include Witty and
Knox (1964), Blackman (1971), Norgren (1973) and Bombin (1984).
More recently, Blinnikov et al. (2001a, 2001b) demonstrated that
phytoliths leave distinct signatures under eight main types of
the forest and steppe communities of the Columbia Basin, WA.
Specifically, ponderosa pine forests can be easily distinguished
based on the presence of diagnostic ponderosa pine "spiny body"
phytolith (see Kerns, 2001 for illustration and details). Fir
and spruce-dominated forests can be distinguished based on
presence of silicified tracheids and blocky cells of spruce.
Potential also exists in distinguishing Douglas-fir dominated
forests based on diagnostic branched asterosclereids of Pseudo-
tsuga (Norgren, 1973).
Blinnikov et al. (2001a) also suggests that phytolith as-
semblages of three types of grassland and a shrub steppe can be
differentiated. Because almost all of the northwestern US
grasses are C3 species producing mostly festucoid rondels, the
classical scheme of Twiss et al. (1969) differentiating between
panicoids, chloridoids and festucoids, is of little use.
However, we found that drier _Agropyron-Poa_ dominated
grasslands have on average much smaller percentage of rondels
than more mesic _Festuca-Koeleria_ dominated grasslands. Fur-
thermore, any grasslands with the presence of _Stipa s.l._ will
be differentiated based on the presence of distinct _Stipa_-type
bilobate form which is different from "classical" panicoid
bilobates. _Aristida_ spp. can be distinguished based on long-
shafted bilobate bodies also described from Aristida in Arizona
and Australia (Kerns, 2001; Bowdery, 1998). Finer distinctions
between, e.g., _Koeleria_ and _Poa_, or between _Calamagrostis_
and _Bromus_ may be achieved (Kerns, 2001; Blinnikov, 1994).
Shrublands with presence of _Artemisia tridentata_ and related
sagebrush species can be separated based on the presence of
abundant blocky forms and fragments of silicified sinuous
epidermis common among dicots, but not grasses. Communities
overrun by cheat brome (_Bromus tectorum_) could be distin-
guished based on high percentage of silicified epidermis forms
is soils, common also in domesticated grasses.
Little work has been done with phytoliths from western North
American wetlands, but studies of sedge phytoliths in Russia and
the Mid-West of the US (Bobrov et al., 2001; Ollendorf, 1992)
suggest that some sedges can be distinguished based on their
phytoliths. Bozarth (1993) and other authors suggest that other
phytolith producers among temperate species include nettles,
elms, oaks, sunflower family and other dicots.
Overall it appears that opal phytoliths can make the most valu-
able contribution when used in combination with other proxy
sources of paleoenvironmental data, such as pollen, stomata,
macrofossils, charcoal, and isotope analysis. Due to con-
siderable redundancy and multiplicity of individual phytolith
shapes it is overall unlikely that we will ever be able to
identify individual species of plants based solely on their
phytoliths. Differentiation of some genera of grasses
(_Koeleria_, _Calamagrostis_, _Festuca_, _Poa_, _Stipa_,
_Aristida_) and subgeneric level identifications in sedges are,
on the other hand, entirely possible. More productive seems to
be to search for unique community signatures in soils based on
all plants found in a particular ecosystem.
Phytoliths in western US can provide valuable information about
the history of paleoenvironments. Some directions of future work
1. enlarging regional phytolith collection both from individual
species and signatures from soils under distinct native and
non-native plant communities
2. fine-tuning existing phytolith classifications for the
region to include all major phytolith morphotypes from
grasses, forbs, and trees
3. expanding paleoenvironmental phytolith research into British
Columbia, Alberta, and Alaska
4. analyzing phytoliths from forested environments and wetlands
in greater detail
5. doing fine scale phytolith studies to resolve local
variability, taphonomy and post- depositional transport
6. exploring possibility of using phytoliths as a direct proxy
for paleoclimates bypassing vegetation reconstructions by
using transfer functions, similarly to how it is done with
pollen (e.g., Webb et al., 1998; see a Phytolith-related
attempt in Fredlund and Tieszen, 1997), or stable isotope
analysis (Stevenson, 1997).
Blackman, E. 1971. Opaline silica bodies in the range grasses of
southern Alberta. _Canadian Journal of Botany_ 49: 769-781.
Blinnikov, M. 1994. Phytolith analysis and the Holocene dynamics
of alpine vegetation. Pp. 23-40 in: Onipchenko, V. & M.
Blinnikov (eds.) _Experimental Investigation of Alpine Plant
Communities in the Northwestern Caucasus._ Veroffentlichungen
des Geobotanischen Institutes der ETH, Stiftung Rbel,
Zurich, H. 115.
Blinnikov, M., A. Busacca, & C. Whitlock. (2001a, in press).
Reconstruction of the Late Pleistocene Columbia Basin
Grassland, Washington, USA, Based on Phytolith Records in
Loess. _Palaeogeography, Palaeoclimatology, Palaeoecology_
Blinnikov, M., A. Busacca, & C. Whitlock. 2001b. A new 100,000-
yr. record from the Columbia Basin, Washington, USA. Pp. 27-
55 in: J. D. Meunier, J.D. & F. Colin (eds.) _Phytoliths:
Applications in earth sciences and human history._ A. A.
Balkema, Rotterdam, the Netherlands.
Bobrov, A. A., Bobrova, E. K., Alexeev Ju. E. 2001. Biogenic
silica in biosystematics: potential uses. Pp. 279-288 in:
Meunier J.D. & F. Colin (eds.) _Phytoliths: Applications in
Earth Sciences and Human History._ A. A. Balkema, Rotterdam,
Bowdery, D. 1998. _Phytolith Analysis Applied to Pleistocene-
Holocene Archaeological Sites in the Australian Arid Zone._
British Archaeological Reports International Series, v. 695.
Bozarth, S. R. 1993. Biosilicate assemblages of boreal forests
and aspen parklands. Pp. 95-105 in: Pearsall, D.M. & D.R.
Piperno (eds.) _Current Research in Phytolith Analysis:
Applications in Archaeology and Paleoecology_ MASCA Research
Papers in Science and Archaeology, Volume 10.
Brown, D. 1984. Prospects and limits of a Phytolith key for
grasses in the central United States. _Journal of Ar-
chaeological Sciences_ 11: 345-368.
Bombin, M. 1984. _On phytoliths, late Quaternary ecology of
Beringia, and information evolutionary theory._ Unpublished
Ph.D. dissertation, University of Alberta, Calgary, Alberta,
Canada. 163 p.
Fredlund, G. G., & L.L. Tieszen. 1997. Calibrating grass
phytolith assemblages in climatic terms: Application to late
Pleistocene assemblages from Kansas and Nebraska.
_Palaeogeography, Palaeoclimatology, Palaeoecology_ 136: 199-
Kearns, B. 2001. Diagnostic phytoliths for a ponderosa pine-
bunchgrass community near Flagstaff, Arizona. _The Southwes-
tern Naturalist_ 46(2): 282-294.
Klein, R. L., & J.W. Geis. 1978. Biogenetic opal in the
Pinaceae. _Soil Science_ 126: 145-156.
Mulholland, S. C. 1989. Phytolith shape frequencies in North
Dakota grasses: a comparison to general patterns. _Journal of
Archaeological Science_ 16: 489-511.
Norgren, J. A. 1973. _Distribution, Form and Significance of
Plant Opal in Oregon Soils._ Ph.D. dissertation, Oregon State
University, Corvallis, OR.
Ollendorf, A. L. 1992. Toward a classification scheme of sedge
(Cyperaceae) phytoliths. Pp. 91-106 in: Mulholland S. & G.
Rapp, Jr. (eds.) _Phytolith Systematics: Emerging issues._
Plenum Press, New York, NY.
Pearsall, D. 2001. _Paleoethnobotany: A Handbook of Procedrues._
2nd ed. Academic Press, San Diego, CA.
Piperno, D. 1988. _Phytolith Analysis: An Archeological and
Geological Perspective._ Academic Press, San Diego, CA.
Runge, F. 1998. _Bibliography of Phytolith Research._ University
of Paderborn, Germany.
Stevenson, B. A. 1997. _Stable Carbon and Oxygen Isotopes in
Soils and Paleosols of the Palouse Loess, Eastern Washington
State: Modern Relationships and Applications for
Paleoclimatic Reconstruction._ Unpublished Ph.D. disserta-
tion, Colorado State University, Fort Collins, CO.
Twiss, P.C., Suess,C.E., and Smith, R.M. 1969. Morphological
classification of grass phytoliths. _Soil Science Society of
America Proceedings_ 33: 109-115.
Verma, S. D. & R. H. Rust. 1969. Observation on opal phytoliths
in a soil biosequence in southeastern Minnesota. _Soil Sci.
Soc. America Proc._ 33: 749-751.
Webb, T. III, K.H. Anderson, P.J. Bartlein, & R.S. Webb. 1998.
Late Quaternary climate change in eastern North America: a
comparison of pollen-derived estimates with climate model
results. _Quaternary Science Reviews_ 17: 587-606.
Wilding, L. P. & L.R. Drees. 1971. Biogenic opal in Ohio soils.
_Soil Sci. Soc. America Proc._ 35: 1004-1010.
Witty, J. E. & E.G. Knox, E. G. 1964. Grass opal in some
Chestnut and Forest soils in north central Oregon. _Soil
Science Society of America Proceedings_ 28: 685-687.
Phytoliths on line:
Mikhail Blinnikov's phytolith gallery:
Terry Ball's phytolith page:
[this link did not work on 2002/02/20]
Deb Pearsal's phytolith web site:
University of Arizona phytolith links:
Glen Fredlund's webpage:
From: "Scott D. Russell" [srussell at ou.edu]
Here's a true challenge. I think you should rush to press at
8:02 pm tonight! Here is an interesting palindrome as the excuse
(which I got from my stepbrother who got from someone else ....
Believe it or not, 8.02pm on February 20 this year will be an
historic moment in time. It will not be marked by the chiming of
any clocks or theringing of bells, but at that precise time, on
that specific date, something will happen which has not occurred
for 1,001 years and will never happen again. As the clock ticks
over from 8.01pm on Wednesday, February 20, time will, for sixty
seconds only, read in perfect symmetry 2002, 2002, 2002, or to
be more precise - 20:02, 20/02, 2002. The last occasion that
time read in such a symmetrical pattern was long before the days
of the digital watch and the 24-hour clock at 10.01am on January
10, 1001. And because the clock only goes up to 23.59, it is
something that will NEVER happen again.
At this palindromic moment we will be [again] in Portland,
Oregon, and I will be sipping Pilsener Urquell with Oluna and my
friends in the Rheinlander. - Adolf
P.S. When I looked at the date posted in BEN, I realized that I
have not changed the year in the two previous BEN issues and
they are labelled as "2001". Can you change it in the web page?
Thanks. - AC
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