BEN # 278

Adolf Ceska aceska at
Sat Dec 8 16:11:27 EST 2001

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No. 278                              December 8, 2001

aceska at                Victoria, B.C.
 Dr. A. Ceska, P.O.Box 8546, Victoria, B.C. Canada V8W 3S2


From: Paul M. Catling [catlingp at] and
   G. Mitrow [mitrowg at]

_Protecting  Canada  from  the  costs  of  introduction of alien
species and contributing to the  control  of  alien  species  is
essential  to  protect  the  Canadian  economy,  environment and
biodiversity. Protection is dependent upon accurate  identifica-
tion. This communication, developed in connection with a request
from  the Canadian Food Inspection Agency, facilitates the iden-
tification of an aquatic plant that is increasingly  being  used
in  the  aquarium trade, but is not likely to be correctly iden-
tified with tools currently available._

It may have been through use  in  malaria  eradication  programs
that  _Egeria  densa_ Planchon became a widespread aquatic weed.
It was promoted as an "oxygenator" in  fish  culture  which  was
considered  very  important in reducing mosquito larvae which in
turn reduced the threat of malaria. Later it was promoted as  an
attractive plant of water gardens and for use in aquaria. It was
also  widely  spread  through  use in experimentation and botany
teaching because of the ease of  viewing  cytoplasmic  streaming
through  the  leaf  lamina that is only two cells thick. It soon
became  naturalized  in  cool  subtropical  and  warm  temperate
regions worldwide. In Canada it has persisted after introduction
in  Vancouver and on Vancouver Island (Catling and Wojtas 1986).
The native range of the two species in  the  genus  _Egeria_  is
restricted to a relatively small region of South America center-
ing on southeastern Brazil (Cook and Urmi-Konig 1984).

In  contrast to _Egeria densa_, _E. najas_ Planchon is much less
well known. It  has  been  used  as  an  aquarium  plant  almost
worldwide, but has apparently not become established outside its
native  range,  although  it  has been reported as "spreading in
aquarist circles" (e.g. Muhlberg 1981). _Egeria najas_  is  cur-
rently  listed  for  sale  by a number of US aquarium plant sup-
pliers under the scientific name and/or the common names "Narrow
leaf Anacharis" and "Light Green Anacharis."  One  advertisement
reads  "_Egeria  najas_  - large new algae buster, $ 2.00 US per
stem." "Algae busters" are "stem plants" that grow  quickly  and
outcompete algae for nutrients contributing to a better aquarium

Recently  (26  November  2001)  unidentified material of _Egeria
najas_ arrived at the Canadian  border  from  Singapore  with  a
question:  was  it  _Hydrilla  verticillata_  (L. _fil._) Royle?
Prior to the production and dispersal of a pamphlet (Jomphe  and
Catling  1994)  that facilitated identification of aquatic weeds
entering Canada, both _Egeria densa_ and _Hydrilla verticillata_
were submitted to the authors for identification frequently, and
both species are still received from time to time, mostly in the
form of fragments, but we had never before  encountered  _Egeria

The question posed by the border authorities was actually a very
relevant  one  because  _Egeria  najas_ looks a little more like
_Hydrilla  verticillata_  than  like  its  closer  relative  _E.
densa_.  The  leaf  serrations of _E. najas_ are conspicuous and
easily seen  without  magnification,  like  those  of  _Hydrilla
verticillata_,  and  quite unlike the leaf serrations of _Egeria
densa_ which can be  seen  only  with  magnification.  Therefore
_Egeria   najas_   could   be  easily  identified  as  _Hydrilla
verticillata_. This potential  problem  is  actually  much  more
serious  than  it may seem because most of the available litera-
ture (e.g. Crow and Hellquist 2000, Haynes 2000), including  for
that  matter  our  earlier  identification  pamphlet (Jomphe and
Catling 1994), only offers a choice between _Egeria  densa_  and
_Hydrilla  verticillata_  without any mention of _Egeria najas_.
This is of course because it has not become naturalized  outside
its  restricted  South American range. Crow and Hellquist (2000)
separate vegetative _Egeria_ from _Elodea_ by leaf  length,  the
former  having leaves 12-40 mm long, the latter with leaves 6-17
mm long. This is a useful, but obviously overlapping  character,
and  material  of  _Egeria  najas_  could be keyed to either _E.
densa_ if it had longer leaves or _Hydrilla verticillata_ if  it
had relatively shorter leaves.

Although  Haynes  (2000)  does  not  mention _E. najas_, his key
separating _Egeria_ and _Hydrilla_ would result  in  identifica-
tion  of  _E. najas_ correctly in the genus _Egeria_ because the
combination of orange-brown hairs on the intravaginal  squamules
and abaxial midvein of leaf with prickles is relatively distinc-
tive  for  _Hydrilla verticillata_. Although relatively distinc-
tive, these characters  are  rather  obscure.  The  intravaginal
squamules (_squamulae intravaginales_) are scale-like structures
on  the  upper  leaf  surface  where it joins the stem (the leaf
axil), but they are only 0.5 mm  long,  and  high  magnification
under  a microscope is necessary to see the fringe. The prickles
on the midvein are also not easily  observed,  but  most  impor-
tantly  they are not always present. Cook and Luond (1982) indi-
cate that _H. verticillata_ "occasionally" bears spines  on  the
on the abaxial (under) surface.

Thus  one has to be familiar with the plant, or to have books on
aquarium plants, in order to be able to identify _Egeria najas_.
Having aquarium plant books is not always the answer because _E.
najas_ is not included in many of them, and in many cases  there
is only a passing mention without any details on identification.
_Egeria  najas_  is  included  in  only  3  of 13 major books on
aquarium plants published since 1986.

Botanists may encounter _Egeria najas_ with increasing frequency
- without knowing it. Even when it is considered there is  still
a  problem  because  existing keys to _Egeria_ rely on flowering
material, whereas botanists often  receive  vegetative  material
for  identification.  The  following  key,  which  we  developed
largely for vegetative material, should prove helpful  in  iden-
tification of Hydrocharitaceae with whorled leaves.

1. Leaves  with obscure serrations or marginal prickles (requir-
   ing magnification to be  readily  observed)  and  leaf  edges
   ...........................  _Egeria densa_ and _Elodea_ spp.

1. Leaves   with   prominent  serrations  or  marginal  prickles
   (readily seen without  magnification)  and  leaf  edges  con-
   spicuously concave or straight between the serrations.

   2. Leaves  long-attenuate,  concave  between  the serrations,
      their midvein without prickles on the abaxial (lower) leaf
      surface; scales in the leaf axis  absent  or  to  0.36  mm
      long,  mostly  smooth-margined  and  lacking  a  fringe of
      orange-brown hairs; internodes mostly  much  shorter  than
      the  leaves  and  up  to 10 mm long 1 dm below the growing
      tip; flowers with round petals and with nectaries
      ..........................................  _Egeria najas_

   2. Leaves linear to attenuate, straight to  slightly  concave
      between  the  serrations,  their  midvein  sometimes  with
      prickles on the abaxial (lower) leaf  surface;  scales  in
      the leaf axis mostly ca. 0.5 mm long, mostly with a fringe
      of  orange-brown  hairs;  internodes mostly as long as the
      leaves and up to 50 mm long 1 dm below  the  growing  tip;
      flowers with linear petals, lacking nectaries
      .................................  _Hydrilla verticillata_

The  specimen  of  _E.  najas_ that arrived from Singapore had a
single female flower with petals 5 mm long and  4 mm  wide,  and
staminodia  less  than  0.5 mm  long.  All leaves were less than
1.5 mm wide. The most recently produced detailed descriptions of
the three species discussed above are in the  revisionary  works
of  Cook  and Urmi-Konig (1984) and Cook and Luond (1982) and in
the earlier Cook et al. (1974).


Catling, P.M. & W. Wojtas. 1986. The  waterweeds  (_Elodea_  and
   _Egeria_  Hydrocharitaceae) in Canada. _Can. J. Bot._ 64 (8):
Cook, C.D.K. & K. Urmi-Konig. 1984.  A  revision  of  the  genus
   _Egeria_ (Hydrocharitaceae). _Aquatic Botany_ 19: 73-96.
Cook,  C.D.K.  &  R.  Luond.  1982.  A  revision  of  the  genus
   _Hydrilla_ (Hydrocharitaceae). _Aquatic Botany_ 13: 485-504.
Cook, C.D.K., B.J. Gut, E.M. Rix,  J.  Schneller,  &  M.  Seitz.
   1974. _Water plants of the world_. Dr. W. Junk. The Hague.
Crow,  G.E.  & C.B. Hellquist. 2000. _Aquatic and wetland plants
   of  northeastern  North   America,   vol.   2,   Angiosperms:
   Monocotyledons._ University of Wisconsin Press.
Haynes, R.R. 2000. Hydrocharitaceae Jussieu, Tape-grass or Frog-
   bit  Family.  Pp.  26-30  in  _Flora North America, vol. 22_.
   Oxford University Press.
Jomphe, M. & P.M. Catling. 1994.  _Restricted  aquatic  plants._
   Agriculture  and  Agri-Food  Canada research branch brochure.
   Cat. No. A22-145. 2 p.
Muhlberg, H. 1981. _The complete guide to water plants._  Inter-
   druck, Leipzig.


From:  Rudolf  Schmid  [schmid at]  (modified
   from reviews and  notices  in  the  November  2001  issue  of
   _Taxon_) and
   Adolf Ceska [aceska at]

Burrows,  George  E.  (Edward)  &  Ronald  J. Tyrl. 2001. _Toxic
   plants of North America._ Iowa State University Press,  Ames.
   vi + 1342 p. ISBN 0-8138-2266-1 [hardback], Price: US$174.95.
   Available  from:  Iowa  State University Press, 2121 S. State
   Ave., Ames, IA 50010-8300, USA (

This massive work devotes 1197 large-format pages to 75 families
sensu lato and innumerable genera, with another 45 pages  on  36
"families of questionable toxicity or [toxic] significance" (the
title  of  chapter 77). The non-angiosperm families treated are:
Cupressaceae,   Cycadaceae,   Dennstaedtiaceae,    Equisetaceae,
Ginkgoaceae, Pinaceae, Pteridaceae, Taxaceae, Zamiaceae, and the
questionably toxic Dryopteridaceae and Ephedraceae.

Some families have extensive bibliographies, as 26 pages for the
grasses. The generic accounts have many illustrations (diagrams,
chemical  formulae,  and  range maps) and detailed descriptions,
with sections  on  taxonomy  and  morphology,  distribution  and
habitat,  disease  problems,  disease  genesis,  clinical signs,
pathology, and  treatment.  Some  accounts  are  incredibly  en-
cyclopedic,  as 13 pages on _Pteridium_ or 17 on _Sorghum._ Many
genera, as _Equisetum, Euonymus,_ and _Sambucus,_ have  keys  to
species.  Some  unexpected genera are encountered, as _Cannabis,
Drosera,_ and _Ginkgo._

This book on North America north of the  Tropic  of  Cancer  is,
obviously  besides  for  taxonomists,  an  invaluable, "complete
information  source  for  veterinarians,  agricultural-extension
agents,   animal   scientists,   horticulturalists,   botanists,
toxicologists, physicians,  pharmacists,  agronomists,  wildlife
biologists,  farmers,  ranchers,  and the general public" (back-
cover blurb). A more economical CD-ROM  should  be  offered.  --
Rudolf Schmid, UC

Cullen,  James.  [Ed.]  2001.  Handbook of north European garden
   plants: with keys to families and genera.  Cambridge  Univer-
   sity  Press,  Cambridge.  vii  +  640  p.  ISBN 0-521-65183-2
   [hardback],  0-521-00411-X   [paperback]   Price:   US$130.00
   [hardback], US$49.95 [paperback]
   Available from:
   Cambridge University Press
   The Edinburgh Bldg., Cambridge CB2 2RU, United Kingdom
   40 West 20th Street, New York, NY 10011-4211, USA

This  is  a  collection  of  keys  to  families  and  genera  of
angiosperms that can be encountered in north  European  gardens.
It  contains  190  families and 2220 genera of flowering plants,
practically almost all that grow or can be  grown  in  temperate
regions  of  the world. The keys and descriptions are taken from
much more comprehensive, six-volume work  "The  European  Garden
Flora"  (for  review  of  its  sixth volume see BEN # 269). Main
families are illustrated with line drawing plates  and  most  of
the illustrations were taken from the _100 Families of Flowering
Plants_  by  Hickey  &  King  (2nd edition, Cambridge University
Press, 2000). The book is a good reference for identification of
temperate families of flowering plants and for identification of
many temperate genera. -- Adolf Ceska

Frodin, David G. _Guide to standard  floras  of  the  world:  An
   annotated, geographically arranged systematic bibliography of
   the   principal   floras,   enumerations,   checklists,   and
   chorological atlases of different areas._  2nd  ed.  14  June
   2001   (date   fide   Frodin).  Cambridge  University  Press,
   Cambridge.  xxiv + 1100  p.  ISBN  0-521-79077-8  [hardback],
   Price: US$240.00. [Ed. 1 1984, xx + 619 p.]
   Available from: - see Cullen above

 A  mighty  oak  has  grown  from  David Frodin's first sapling,
_Guide  to  the  standard  floras   of   the   world   (arranged
geographically),_  which  was  released in August 1964 as a mere
64-page typescript. I proudly keep this  next  to  the  639-page
first  edition,  _Guide to standard floras of the world_ (1984),
and now the just published 1124-page edition of the same title--
a fine display of evolution in  action.  Indeed,  some  in  1964
might  have  regarded that sapling sappy in view of its competi-
tion, Sidney Fay Blake & Alice Cary Atwood's _Geographical guide
to the floras of the world,_ part 1 (1942, [[i]], 336  p.),  and
Blake's  part  2  (1961, [[i]], 742 p.), both of which, inciden-
tally, cost me $10.42 in April 1975. However,  Frodin's  _Guide_
has become a major contribution to botanical bibliography.

This  work  contains some marvelous mini-essays that can be read
in their own right and impressive historical  reviews.  Coverage
is  for floras from 1840 through 1999, with some works published
in 2000 listed in the five-page addendum.

My only criticisms involve the indices. The massive author index
(108 pages) might better have been replaced  by  a  title  index
because  many floras published as continuing series change their
authorship or editorship over the decades. In addition, the more
useful geographic index (20 pages) would have been better placed
after the author index, not before it.

The old master was always right on the mark. Frans A.  Stafleu's
comments  (_Taxon_  34:  558,  1985) about the first edition are
still very much apropos: "The detail and the precision  of  this
work  are impressive; the author is to be congratulated for this
major achievement."

Electronic distribution is planned via EBRARY
(, as is possibly a CD-ROM. [Modified from
_Taxon_ 50: 967-968 (August 2001)] -- Rudolf Schmid, UC

Gilkey, Helen M. (Margaret) & La Rea J. (Johnston) Dennis. 2001.
   _Handbook of northwestern  plants._  Rev.  ed.  Oregon  State
   University  Press, Corvallis. [v] + 494 p. ISBN 0-87071-490-2
   [paperback] Price: US$29.95. [Ed. 1 1967, x + 505 p.]
Gilkey, Helen M. & Patricia L. Packard. 2001. _Winter  twigs:  A
   wintertime  key to deciduous trees and shrubs of northwestern
   Oregon and western Washington._ Rev. ed.  x + 118  p.  Oregon
   State University Press, Corvallis. ISBN 0-87071-530-5 [paper-
   back]  Price:  US$19.95. [Ed. 1 1962, viii, [[i]], 109 p., in
   _Oregon State monographs, studies in botany,_ no. 12.]
   Available from: Oregon  State  University  Press,  101  Waldo
   Hall, Corvallis, OR 97331-6407, USA

Oregonians  north  of  the  Umpqua  Divide (roughly Lane Co. and
northward) and Washingtonians living betwixt the  Pacific  Coast
and  the  crest  of  the  Cascades will definitely welcome these
revisions of two classic books by Helen Margaret  Gilkey  (1886-
72).  She  was a professor and herbarium curator at Oregon State
University for over 30 years. Her _Winter twigs_ updates a  1962
book  whereas her _Handbook_ updates a coauthored 1967 book that
in turn was based on  various  solo-authored  predecessor  works
dating  back  to 1929. Gilkey's associates did the current revi-

The new edition of the _Handbook_ rather closely  resembles  the
old.  However,  revisions  were extensive, though mostly subtle,
namely: increasing the size of  the  printed  page  by  about  a
quarter (from 210x133 to 229x154 mm); including (on p. 6) a list
of  the 115 treated families indexed to pages (such a list would
be much better placed on an endpaper rather than here the  banal
scale  and  table  of metric, English conversions); numbering of
couplets of most of the keys; changing page headers from  common
names  to  Latin names of families; reassigning some taxa (e.g.,
_Ribes_  from  Saxifragaceae   to   Grossulariaceae);   updating
nomenclature;  revising  descriptions;  adding a few species (no
stats are given); and arranging genera  and  species  alphabeti-
cally   within  families,  although  these  are  still  arranged
taxonomically within the pteridophytes (ferns, then  non-ferns),
gymnosperms, mono-, and dicotyledons. The book has some new line
drawings  but  overall  is still sparsely, though adequately il-
lustrated. Significant introductory information  on  the  region
covered or its vegetation is still missing.

Those  of  us  raised on William M. Harlow's _Fruit key and twig
key to trees and shrubs ... of  eastern  North  America_  (1941,
1946,  a combined reissue in 1959) that was used during the dull
botanical season will be surprised that the more temperate  west
has  an  equally  valuable  work in the same vein. Gilkey's twig
book was nomenclaturally updated and typographically  modernized
but  otherwise  is nearly identical to its 1962 predecessor. The
Englerian sequence of taxa, the excellent eleven-page  introduc-
tion,  and  the  artwork, including Gilkey's simple drawings and
Packard's 15 fine plates (the revision does not mention  Packard
for  these)  are  unchanged.  The  revision  has  minor  textual
changes; for example, the key has 80 couplets versus 81 formerly
because  _Sorbus  occidentalis_  and  _S.  sitchensis_  are  now
treated  as  _S.  sitchensis_  var.  _grayi. _The book treats 16
families, 35 genera, and 79  mostly  native  species  (including
_Salix_  sp.--not  the  17 families and 82 species touted on the
back cover) and nicely illustrates all but  three  taxa  (_Alnus
rhombifolia,_  twigily  indistinguishable  from  _A. rubra,_ and
_Spiraea betulifolia var. lucida_ and  _Symphoricarpos  mollis,_
twigily similar to _Sp. densiflora_ and _Sy. albus_).

Both  books  cover the same region and would have benefited from
an area map  with  a  few  place  names  (e.g.,  the  Willamette
Valley).  The  distributions given are very generalized. This is
especially unfortunate for the twig book. Simply adding  British
Columbia  and  California to the appropriate distributions would
have provided much information. For instance, for the twig  book
comparing  its  79  species (nomenclature is based on the Oregon
Flora  Project--  with   those   in
California (Jepson Flora Project--  --the  two  databases
should eventually be compared to show overlap, or lack  thereof)
reveals a whopping 68 species common to Oregon and California. A
corollary  of  this is that the book unjustly excludes southwes-
tern Oregon (see  the  Umpqua-Divide  statement  beginning  this
review),  which  also has these 68 species plus probably some of
the remaining 11.

These works are usable at  all  levels  from  the  knowledgeable
(i.e.,  one  who  can  use  keys) wildflower, shrub, or tree en-
thusiast to the  professional  botanist.  Gilkey  wrote  several
other  regional  floras,  which  one hopes are in the process of
being updated. -- Rudolf Schmid, UC

Goodman, Jordan & Vivian  Walsh.  2001.  _The  story  of  taxol:
   Nature  and  politics in the pursuit of an anti-cancer drug._
   Spring   2001.   Cambridge   University   Press,   Cambridge.
   xiii + 282 p. ISBN 0-521-56123-X [hardback] Price: US$27.95
   Available from: - see Cullen above

An  essential  book  for botanical reference libraries. Taxol is
"the best-selling anti-cancer drug ever,  with  world  sales  of
$1.2  billion  in  1998"; the book, "from a broader perspective,
... uses taxol as a paradigm to address current  issues  in  the
history  and  sociology  of  science  and medicine" (dust-jacket
blurb). Historian Goodman also wrote _Tobacco  in  history:  The
cultures  of  dependence_  (Routledge,  London, 1993). -- Rudolf
Schmid, UC

McGary, [Mary] Jane  (ed.).  2001.  _Bulbs  of  North  America._
   Timber  Press,  Portland,  and  North  American  Rock  Garden
   Society.  251  p.  [56]  pls.  (col.),   ISBN   0-88192-511-X
   [hardback], Price: US$34.95
   Available from:
   Timber Press, Inc., The Haseltine Building
   133 S.W. Second Ave., Suite 450, Portland, OR 97204, USA
   Tel.: 1-800-327-5680 or 1-503-227-2878, Fax: 1-503-227-3070 (e-mail: orders at

_Contents:_  foreword by B. Mathew; intro (by ed.); M. McDonough
et al. on _Allium;_ A. W. Meerow on Amaryllid.; P.  Sanderson  &
ed.  on _Brodiaea_ alliance; F. Callahan on _Calochortus;_ M. M.
Grothaus on _Erythronium;_  D.  King  on  _Fritillaria;_  M.  E.
Chelednik  on se. Iridaceae; E. A. McRae on _Lilium;_ L. Russell
on nw. bulb taxa; M. Irish on sw. idem; C. Colston Burrell on e.

An excellent work, very useful taxonomically,  because  "special
attention  [was] paid to identifying the distinguishing features
of the species" (dust-jacket blurb); with much much  information
on  range,  elevation,  and and ecology, 101 color photos, 6 B&W
line  drawings.  (See  also  )  --  Rudolf
Schmid, UC

O'Connor,  Georganne  (P.)  & Karen (J.) Wieda. 2001. _Northwest
   arid lands: An introduction  to  the  Columbia  Basin  shrub-
   steppe._  Battelle  Press,  Columbus.  xiii + 218  p. ISBN 1-
   57477-103-5 [paperback], Price: US$18.95

   Available from:
   University of Washington Press
   Box 50096, Seattle, WA 98145-5096, USA

A most informative work,  nicely  and  colorfully  done,  though
rather web-style. -- Rudolf Schmid, UC

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