BEN # 280

Adolf Ceska aceska at victoria.tc.ca
Tue Jan 22 04:05:31 EST 2002


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No. 280                              January 22, 2001

aceska at victoria.tc.ca                Victoria, B.C.
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 Dr. A. Ceska, P.O.Box 8546, Victoria, B.C. Canada V8W 3S2
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A RADICAL VIEW OF BRYOPHYTE BIOLOGY:
MOSSES ARE FROM MARS, VASCULAR PLANTS ARE FROM VENUS
From: Brent Mishler [bmishler at socrates.berkeley.edu]

In what ways does bryophyte biology differ from that of vascular
plants  (tracheophytes)?  The  short answer: in almost every way
possible! The groups didn't evolve  on  different  planets,  but
their  differences  could  almost  make you think they did. They
certainly adopted very different  approaches  to  being  a  land
plant  on  this  planet.  Many aspects need much more study, but
what is known about bryophyte biology suggests that  in  general
the  bryophytes  differ  in most ways in their biology, ecology,
and evolution from tracheophytes.

Major differences in bryophyte biology  from  tracheophytes  in-
clude:

 1. _Haploid dominance in the alternation of generations._
    The  green,  vegetative part of the life-cycle in bryophytes
    is haploid. Without the genetic benefits of dominance, genes
    acting in the gametophyte are presumably  subject  to  rela-
    tively severe selection.

 2. _Extensive phenotypic plasticity._
    Studies  have  shown  that bryophytes tend to have very high
    amounts of morphological and physiological plasticity.  This
    may compensate for their demonstrated low levels of ecotypic
    differentiation (perhaps due to haploidy).

 3. _Poikilohydry and desiccation-tolerance._
    Poikilohydry is the rapid equilibration of the plant's water
    content to that of the surrounding environment, while desic-
    cation  tolerance is the ability of a plant to recover after
    being air-dry at the cellular  level.  All  bryophytes  have
    these  abilities  to  some  extent, but this was lost in the
    larger, more complex, and endohydric tracheophytes.

 4. _Need for free water for sexual reproduction._
    A residual feature of the early  land  plants  is  the  con-
    straint imposed by the swimming sperm. Swimming gametes have
    short dispersal distances which leads to frequent inbreeding
    in  monoicous  species  and lack of sporophyte production in
    dioicous species.

 5. _The clump as a "super-organism"._
    Many mosses  and  some  liverworts  are  essentially  social
    organisms.  This  results  from  the  combination  of clonal
    growth, poikilohydry, and  external  water  conduction.  The
    plants  in  a  clump  are  subject to natural selection as a
    group. Intimate contact of each  vegetative  cell  with  the
    environment, due to poikilohydry, lends itself to interplant
    chemical communication via pheromones.

 6. _Heavy reliance on asexual reproduction._
    Due  to  the  difficulty  of  achieving  fertilization, many
    bryophytes have evolutionarily  lost  functional  sexuality.
    Since  bryophytes grow from an apical cell, somatic mutation
    allows genetic variation even within clones.

 7. _Small stature and the occupation of microhabitats._
    Small size, lack  of  roots,  and  poikilohydry  means  that
    bryophytes  are  in  a  close  relationship  with only their
    immediate microenvironment. Over geological time,  they  may
    be  less  influenced  by  climatic  change,  and  linger  in
    refugial habitats.

 8. _Less selection pressure from the biotic  component  of  the
    environment than from the physical component._
    Vagility  and  establishment  abilities  of  bryophytes  are
    relatively poor. Available substrates are not filled in most
    mesic and xeric environments (although they may be  in  some
    hydric  environments).  The  presence  of  other  bryophytes
    nearby often appears beneficial to growth.

 9. _Relatively slow evolutionary rates in morphology._
    The fossil record of bryophytes indicates that ancient forms
    are  very  similar  to   modern   ones.   Biogeographically,
    bryophytes  tend  to  follow the same historical patterns of
    disjunction as  tracheophytes,  but  at  a  lower  taxonomic
    level. This may indicate that developmental constraints play
    an unusually important role.

The overall effect of these features on the evolutionary ecology
of  bryophytes  makes  them  profoundly  different.  By studying
bryophytes  and  comparing   their   life-style   to   that   of
tracheophytes,  we can learn to observe structure closely, think
critically about evolutionary  inferences,  and  comprehend  how
different  lineages  can  take  different  functional  paths  in
response to the same stimuli.

[Abridged from Mishler, B.D. 2001. "Book review - The biology of
bryophytes:  Bryophytes  aren't   just   small   tracheophytes."
_American  Journal  of  Botany_  88:  2129-2131.  - A review of:
_Bryophyte Biology._ by A. Jonathan Shaw  and  Bernard  Goffinet
(eds.).  2000.  Cambridge University Press. x + 476 p. - For the
review of this book by Wilf Schofield see also BEN # 259.]


BOOK REVIEWS AND NOTICES
From: Adolf Ceska [aceska at victoria.tc.ca]

Jacobsen, Arthur Lee. 2001. _Wild plants of Greater  Seattle:  A
   field  guide  to native and naturalized plants of the Seattle
   area._ Arthur Lee Jacobson, Seattle. 494 p. ISBN 0-9622918-2-
   x [softcover] Price: US$24.95
   Available from: Arthur Lee Jacobson,  2215  E.  Howe  Street,
   Seattle,  WA  98112  e-mail:  alj at consultant.com;  web  site:
   http://www.arthurleej.com

Line drawings (most of them by J.R. Janish from Hitchcock et al.
_Vascular plants of the Pacific Northwest_)  accompany  descrip-
tions  of  about  500  vascular plants. The descriptions contain
information about the main diagnostic characters,  intraspecific
variation, biology and ethnobotany of each species. Forty intro-
ductory  pages  list plants of various habitats, summarize their
edibility and give month-by-month accounts of  their  phenology.
An annotated checklist of about 1,270 species gives more details
on their distribution in the Greater Seattle area.


Kershaw,  Linda,  J.  Gould,  D. Johnson, & J. Lancaster [eds.].
   2001. _Rare vascular plants of Alberta._  University  of  Al-
   berta Press & The Canadian Forest Service, Edmonton, Alberta.
   xliv+484 p. ISBN 0-88864-319-5 [softcover] Price: CDN$29.95
   Available from:
   Raincoast Books,  9050 Shaughnessy Street
   Vancouver, BC, CANADA  V6P 6E5
   Customer service: 1-800-511-6024  Fax: 1-800-565-3770
   E-mail: custserv at raincoast.com or info at raincoast.com
   Internet: http://www.raincoast.com

This  publication  describes  approximately  485 vascular plants
that are considered rare in Alberta. In  a  one-species-per-page
format,  this  manual gives the name of the species, most common
synonyms, description, habitat and  notes  on  similar  species.
Species  are  illustrated  with  colour  photographs and/or line
drawings, and for most species, maps of  their  distribution  in
North  America and in Alberta are provided. The work is a result
of intensive floristic surveys  that  included  30  direct  con-
tributors and about 100 amateur botanists.

Besides  the species treatments, the book gives a good introduc-
tion to problems of rare plant studies, and a  good  description
of  the  phytogeography  of  Alberta. Several appendices provide
interesting reading (yet another  key  to  Alberta  _Botrychium_
species!),  and an illustrated glossary and close to 300 litera-
ture citations conclude this handy publication.

When I first opened the book, I had the impression that  it  was
yet  another book in the successful plant guide series published
by Lone Pine Publishing. Not so. However, although it  was  pub-
lished  by  the  University  of  Alberta,  editor Linda Kershaw,
formerly of Lone Pine, had an obvious and significant  influence
on  the  format  of  this publication. The University of Alberta
Press, Canadian Forest Service,  Alberta  Native  Plant  Council
(Alberta's own version of a Native Plant Society), four editors,
30 contributors and about 100 volunteers should be commended for
this great book.


Phipps,  James  B. & Paul M. Catling. [Eds.] 2001. _Bioconserva-
   tion and systematics: proceedings of the  Canadian  Botanical
   Association  Conference  Symposium  in  London, Ontario, June
   2000_. Canadian Botanical  Association,  Ottawa.  iii+101  p.
   ISBN 0-9689565-0-5 [softcover] Price: CDN$23.00 (US$17.00) in
   Canada and USA, CDN$33.00 (US$21.00) overseas.

   Ordering information:
   Send a check made out to "Canadian Botanical Association" to:
   Dr. Mel Fisher
   Box 160
   407 Main Street
   Aberdeen, Saskatchewan
   Canada S0K 0A0
   Prices include shipping and handling.

This is a collection of papers presented at the "Bioconservation
and  Systematics"  symposium organized by the Canadian Botanical
Association (CBA/ABC) at the annual general meeting in 2000. The
symposium addressed the theme common to other similar  symposia,
such  as one organized by the Missouri Botanical Garden (_Annals
of the Missouri Botanical Garden_, vol. 87, no. 1, 2000)  or  by
the  Jepson Herbarium (_Madrono_, vol. 47, no. 2, 2000): What is
the role of biosystematics in the exploration  and  preservation
of plant biodiversity?

The  symposium  organized  by the Canadian Botanical Association
included the following contributions:

Bioconservation and Systematics - Symposium Introduction  (James
   Phipps)
A  never-ending  role  for  biosystematics  in the protection of
   vascular plant biodiversity in Canada (Paul Catling),
Planning with plants in Illinois (Kenneth Robertson),
The role of Conservation Data Centres  in  the  conservation  of
   Canada's flora (Michael Oldham & Peter Sorrill),
Floristics  and  conservation: an example from Newfoundland (Luc
   Brouillet),
Evaluating hybridization as a cause for species endangerment:  a
   role  for  systematics in plant conservation (Brian Husband &
   Kevin Burgess), and
Can conservation help conserve rare plants in  the  twenty-first
   century? (Anton Reznicek).


PALINDROMES REVISITED

My  posting  on  palindromes  stimulated  more  "Letters  to the
editor" than any other botanical posting in BEN. - AC

Costas A. Thanos [cthanos at biol.uoa.gr] wrote:

In regard to the palindromic phrase in BEN 279, a few comments:

 1. The phrase was 'invented' by Byzantine Greeks (the  'middle'
    ones,  not  ancient  Greeks)  - so it was an early Christian
    phrase.
 2. The original inscription was  made  on  a  fountain  outside
    Saint  Sophia,  in  Constantinople (today Istanbul, Turkey),
    the capital of the Byzantine Empire. It was made during  the
    6th century AD, during the reign of Emperor Justinianus (who
    commanded the construction of the magnificent cathedral).
 3. The correct translation is: 'Wash sins not only face'.

The  Greek word (although palindrome is perfectly Greek as well)
for the phrases that can be read both ways is 'cancer phrase' or
'cancer text'. Cancer is crab of course.

The spelling in Greek is

Î^ÝÎ^ÙΨÎ^ßÎ^Ý Î^ÑÎ^ÝÎ^ßÎ^ÜÎ^×Î^ÜÎ^ÑΤÎ^Ñ Î^ÜÎ^× Î^ÜÎ^ßÎ^ÝÎ^ÑÎ^Ý Î^ßΨÎ^ÙÎ^Ý

- I guess you will need  to  install  Greek  fonts  to  read  it
properly. The transliteration you used in the BEN is the closest
possible phonetically.

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