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BEN # 199
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No. 199 July 26, 1998
aceska@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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GRASSES OF THE TRIBE HORDEAE IN NORTH AMERICA: 3. COMMENTS
From: Mary Barkworth <stipoid@cc.usu.edu>
AEGILOPS and TRITICUM: These will be treated as separate genera
in the Manual of Grasses for the Continental United States
and Canada (henceforth the Manual). They are morphologically
and ecologically distinct but the cytological and evolution-
ary arguments for treating them as a single genus are ex-
tremely strong.
AGROPYRON: One of the relatively few points of agreement in the
perennial Hordeae is that Agropyron should be restricted to
the crested wheatgrasses. The problems left are a) what to do
with the ex-Agropyrons and b) to determine which taxa are
present in North America. The treatment I have used before,
in which three "species" are recognized, is artificial.
DASYPYRUM: A well accepted annual genus that is known in North
America only from a historical collection of Dasypyrum vil-
losum that was made in Pennsylvania.
ELYMUS: This I interpret as including Sitanion, Roegneria,
Elytrigia, and Hystrix as well as several species that used
to be in Agropyron. SITANION is a North American taxon. It
is, I agree, morphologically distinctive, but it hybridizes
readily with species of Elymus. This last does not preclude
it being recognized as a genus, but I have not done so in the
Manual treatment. ROEGNERIA is accepted by Baum and most
Chinese taxonomists, but it is even harder to distinguish
from the bulk of Elymus than Thinopyrum. Baum et al. (1991)
transferred some North American species to Roegneria but, in
my opinion, they do not belong in that taxon, no matter at
what level it is recognized. ELYTRIGIA: The type species of
Elytrigia is E. repens. It looks, in overall habit, very like
other species of Elymus, but was kept in a separate genus
partly because of its strongly rhizomatous habit and partly
because it hybridizes with other species that I include in
Thinopyrum but others included in Elytrigia. HYSTRIX: This
taxon presents a problem. There is reasonable evidence that
its type species belongs in Elymus, but there is also
evidence suggesting that Hystrix californica is more closely
related to Leymus than Elymus. For now, I include H. califor-
nica in Elymus with which it agrees in overall habit and
habitat preference. EX-AGROPYRONS: Some of the other species
that have been transferred from Agropyron to Elymus are
Agropyron trachycaulus (= Elymus trachycaulus), Agropyron
boreale (= Elymus alaskanus), and Agropyron dasystachyum
(= Elymus lanceolatus).
EREMOPYRUM: A well-accepted annual genus of which one species,
Eremopyrum triticeum, is fairly common in North America. It
looks like an annual crested wheatgrass and grows in dis-
turbed sites.
HORDEUM: This will be treated in its traditional sense.
LEYMUS: This genus consists of several alkaline tolerant
species. Its members fall into two morphologically distinct
groups, one shoreline and primarily coastal, the other inland
and non-shoreline. At one time, it was believed to consist of
allopolyploids that combined the genome in Psathyrostachys
with that found in Thinopyrum. More careful checking revealed
that there is no evidence for presence of the Thinopyrum
genome in Leymus.
PASCOPYRUM: A monotypic octoploid genus whose only species, P.
smithii, is an alloploid derivative of Elymus and Leymus. It
is often misidentified, either as Elymus lanceolatus or as
Leymus triticoides.
PSATHYROSTACHYS: A Eurasian genus of approximately 22 species.
It is generally accepted by Eurasian taxonomists. The only
species in North America, P. juncea looks very like Leymus
cinereus, differing chiefly in having tidier looking spikes.
Yes, that is how I think of it. I am told that the other
species are quite distinct from Leymus, but the two genera
share at least one genome.
PSEUDOROEGNERIA: A genus of approximately 20 species, only one
of which occurs in North America, P. spicata. I am assured by
those that know the other species in their natural habitat
that the genus is morphologically and ecologically distinct
from Elymus. The native species differs from Elymus in its
skinnier culms and leaves.
SECALE: An exceptional genus in the Hordeae being a Linnaean
genus about whose generic limits there is no argument. It has
two species but only Secale cereale is known to be estab-
lished in North America.
TAENIATHERUM: Like most annual genera (Aegilops and Triticum are
notable exceptions), Taeniatherum has been widely accepted.
Its only species, Taeniatherum caput-medusae, used to be
included in Elymus.
THINOPYRUM: One of the more controversial genera in the tribe.
The representatives that I know have distinctive, thick,
inflexible glumes that are truncate, obtuse,or acute, trul-
late spikelets, and florets that are slow to disarticulate.
Two species are common in North America, T. ponticum (the old
Agropyron elongatum as interpreted by A.S. Hitchcock) and T.
intermedium.
Postscript: The treatment of many North American species also
needs considerable further study. The fact that one or two
accessions of a species form fertile hybrids on an experimental
farm does not guarantee that such hybrids form naturally, nor
that, if they do so, that they are capable of becoming estab-
lished. There is also a need to obtain experimental information
on how much phenotypic plasticity is present in a population.
Such plasticity, particularly in predominantly selfing species,
could lead to the formation of morphologically distinct entities
of little taxonomic significance.
MISSOURI BOTANISTS HAVE DOUBTS ABOUT REGISTRATION OF PLANT NAMES
Abbreviated from a posting on TAXACOM discussion list.
Formal registration of plant names is a new concept which will
be voted on at the Nomenclature Session of the next Interna-
tional Botanical Congress, St. Louis, 1999. [See BEN # 185, Feb.
28, 1998]
Botanists in the Research Division of the Missouri Botanical
Garden have carefully studied the arguments and mechanism for
registration, as published and demonstrated to date (see
http://www.bgbm.fu-berlin.de/iapt/registration/default.htm).
They are almost unanimous in opposing it for two fundamental
reasons:
1. The botanical community would for the first time depend on
the authority of a single organization (the International
Association of Plant Taxonomist - IAPT) for the valid publi-
cation of names, in contrast to the present practice of
independent and unencumbered publication in a book or jour-
nal.
2. Registration would not usefully and significantly add to the
nomenclatural information already available; instead it
would duplicate or replace effective systems.
In addition, the Missouri botanists see serious problems in the
mechanism for registration that seem not to have been addressed.
They urge all IAPT members and institutes to study the informa-
tion presented, and then weigh the pros and cons before voting
on registration at the St. Louis Congress.
The full text of this discussion paper is available at:
http://www.mobot.org/MOBOT/research/registr.html
In the discussion triggered by this position paper, Dr. Joseph
Laferriere <josephl@aztec.asu.edu> asked:
"Under the registration proposal as currently envisioned, how
can a reader tell from looking at a newly published name in a
journal whether or not it has been registered? Under the current
system, I can tell within 30 seconds whether or not a new name
has been validly published." "Under the registration proposal,
as I understand it, I now have to ask whether the editors ful-
filled the registration requirements."
NORTH AMERICAN FESCUES (FESTUCA, POACEAE) ON CD-ROM
From: Adolf Ceska <aceska@victoria.tc.ca>
Aiken, S.G., M.J. Dallwitz, C.L. McJannet, & L.L. Consaul. 1997.
Fescue grasses of North America. Canadian Museum of Nature,
Ottawa. CD-ROM (runs under MS-WINDOWS 3.1, 95, or NT).
Available from: Publications Department, Canadian Museum of
Nature, P.O.Box 3443, Station D, Ottawa, Ontario, Canada K1P
6P4 Phone (613) 566-4292, 1-800-263-4433 (Canada & U.S.A.);
FAX (613) 566-4763; e-mail: rmartin@mus-nature.ca
Please inquire about the price; I heard it's minimal, just to
cover handling and shipping ( < CDN$10.00).
This CD-ROM contains a taxonomic monograph of 46 species and
subspecific taxa of North American fescues. The species treat-
ment gives details on the type specimen, synonymy, morphological
description, habitat, distribution, chromosome numbers, and
miscellaneous comments. There are more than 200 images linked
with the descriptions.
The information is based on 16 years of research on the genus
Festuca and is maintained at the Canadian Museum of Nature in a
DELTA data base. The interactive identification and information
retrieval package, which is an integral part of the DELTA system
provides an easy access to the information and offers a powerful
method of interactive identification (INTKEY).
This is a truly remarkable work. I would like to thank
1. Dr. Susan Aiken and her colleagues for their taxonomical
work,
2. Dr. Dallwitz and the DELTA team for releasing the INTKEY
program for the use with with this package, and
3. the Canadian Museum of Nature for producing this CD-ROM.
If you don't have the CD-ROM drive, visit this web site:
http://biodiversity.uno.edu/delta/festuca/index.htm
That site contains almost the same information that is on the
CD-ROM. For more information on the Festuca DELTA set see:
Aiken, S. et al. 1997. Canadian Journal of Botany 75: 1527-1555.
What about other CD-ROM sets? The Canadian Museum of Nature
produced a set on the saxifrages of the Canadian Arctic - I have
not seen that one. I know, however, that Dr. George Argus has a
sophisticated DELTA set of North American willows. Would it be
possible to produce a similar CD-ROM with his treatment of
North American willows?
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