The chromosome number of Saxifraga gaspensis Fernald

5 Pages·1995·2.3 MB·English

by  C Gervais

RHODORA,
No. 171-175, 1995
Vol. 97, 890, pp.
CHROMOSOME NUMBER
OF
THE
FERNALD
SAX FRAG GASPENSIS
A
I
Norman and Trahan
Dignard, Rosaire
Camille Gervais,
ABSTRACT
The chromosome number of Saxifraga gaspensis Fern., a laxon frequently
was
included in the circumpolar species S. nivalis L., or considered a variety,
determined on material from Mount Logan, Gaspe Peninsula, and found to be
= =
In As chromosome number of In 60 (about 30 data from
40. the 5. nivalis is
diverse countries), seems that the plant described by Femald in 1917 is spe-
it
The authors suggest that gaspensis could be a stabilized
cifically different. S.
relictual hybrid between S. nivalis and the closely related diploid species S. tenuis
=
from
(Wahlenb.) H. Smith, 2n 20, or a polyploid originating S. tenuis.
chromosome number,
Key Words: Saxifraga gaspensis, S. nivalis, S. tenuis, dis-
Canada
endemism, Gaspe Peninsula, Quebec,
tribution,
taxonomic
history
M
was by
gaspensis described
ifraga
m
material
Mountain (Mount
on the Gaspe Peninsula and distributed in herbaria as S.
first
The new from circumpolar
nivalis L. species differed the arctic-
more
alpine nivalis by "rosette-leaves narrowly cuneate-
S. its
obovate and more gradually narrowed to a broad petiolar base,"
which were
numerously flowered inflorescences spicate-
less
its
racemose than spiciform corymbiform, shorter calyx
rather to its
and narrower
lobes reflexed in acute to subacute petals
fruit, its
and
shorter capsules.
its
was moist
discovered
In the following decades, S. gaspensis in
Mount Mount
and on Logan and Blanc, west of
pockets ravines
Quebec
and was reported from northern
the type locality, also
it
and Labrador (Rousseau, 1974), Although retained as a dis-
still
Manual
synonym
Wahlenb. more recent treatments (Scoggan, 1978; Kartesz,
in
name
Hulten on the other hand, uses the S. gas-
1994). (1971),
maps
from Only Boivin (1966 and unpubl) con-
S. nivalis var. tenuis.
Boivin]
sidered gaspensis [sub nivalis var. gaspensis (Fern,)
S. S.
from and sensu
taxon tenuis
as a differing S. nivalis 5^. stricto.
171
Rhodora
172
97
[Vol.
However, documented
in recent catalogs or of en-
rare,
lists
dangered or vulnerable species in Canada or in Quebec (Bouchard
Argus and
et al., 1983; Pryer, 1990; Lavoie, 1992), S. nivalis var.
gaspensis revived taxon need of
is as, at least, a in further research.
For this reason and because of the urgent problem of determining
must
if S. gaspensis be included, or not, in the of species to
list
be was
legally protected, the present study undertaken.
AND
MATERIAL METHODS
material
of 1993 in cold chimneys of Pease Basin on
;t
Mount
Logan, greenhouse Addi-
for culture.
specimens
Mounts Dodee and Griscom
1993 For
stations. the cytological studies, fresh root tips were
from
selected potted plants and from germinating on wet
seeds
They
filter papers in Petri dishes. were fixed in an acetic acid/
mixture
treatment
fixation, the potted plants or the Petri were kept in a refrigerator
4^C
at for 4 to 7 hours.
AND
RESULTS
DISCUSSION
=
The chromosome number
In 40 was determined
(Figure
1)
on one of the potted plants and two plantlets obtained from seeds
collected in 1993 in Pease Basin. The same chromosome number
^
{In was observed on 1994 from
ca. 40) also the material Big
chromosome number
Cascade. This from numerous
the
differs
= =
counts reported for S. nivalis {In 60) and S. tenuis {In 20)
on circumpolar material from Greenland, Nor-
Iceland, Spitzberg,
way, Siberia, Alaska, British Columbia, Northwest
Territories,
etc. with the exception of a report by Krause and Beamish (1973)
who ^
have found n 10 on one specimen of group from
this the
Yukon
territories (Lapie Lake). These authors do not attempt
to
= ^
attach any binomial to the cytotypes {n 20, n 10) they have
Yukon
found them
in the but describe as belonging to a large
S.
Our chromosome
complex.
nivaliS'tenuis however, were
data,
specifically determined from specimens which were suspected
to
—
173
Gervais ah Saxifraga gaspensis
et
1995]
Mm
10
Figure Somatic chromosomes of Saxifraga gaspensis Fern.; metaphase with
1
,
=
In 40 chromosomes from a root-tip
cell.
we
taxon
be gaspensis, so that are inclined to consider this as
S.
from and
basically different S. nivalis S, tenuis.
=
The chromosome Krause and Beamish
count (n 20) of (1973)
Yukon
between
in the possibly belongs to a hybrid individual S.
4 = =
and two growing
nivalis {2n 60) S, tenuis {In 20), the species
together in this region where their differences ''seem to break
down and appear Krause and Beamish
the plants to intergrade'' as
may
out The same northern
point situation also prevail in
(1973)
Quebec and Labrador where mention of "5^.
the gaspensis''' refers
perhaps such hybrids.
to
same
hybrid
quite possible that S. gaspensis shares the
It is
=
Gaspe
origin but, as S. tenuis {In 20) is not reported for the
=
Peninsula and sensu {In possibly does not
S. nivalis stricto 60)
we must
exist there either, suppose that S. gaspensis is a relictual
stabilized hybrid able to reproduce and set viable seeds. This
Rhodora
174 [Vol.97
when
event could have occurred the Gaspe Peninsula climate and
flora were different and comparable to the actual situation in the
Another
arctic. possibility that S. gaspensis a tetraploid
is is off^-
spring of tenuis but an ancient origin must also be advocated
5.
in this case.
The
study of the meiosis in gaspensis could perhaps provide
S.
an answer to these questions but a cytological examination of
Gaspe
different populations of S. nivalis sensu lata in the Pen-
may
insula and in northern Quebec be necessary to understand
the whole problem. can already be recommended, however,
It
complex Gaspe
that the taxa belonging to the S. nivalis in the
Peninsula be protected an endangered
as local taxa.
ACKNOWLEDGMENTS
The authors would like to express their gratitude to Michele
Dr Munson
Parent for help in field trips, to Alison for revision
Gagnon
of the English manuscript, to Jean and Gildo Lavoie for
helpful discussions and to Andree Rodrigue for the typing of the
text.
LITERATURE CITED
Argus, G. W. and K. M. Pryer. 1990. Les plantes vasculaires rares du Canada.
Musee
Notre patrimoine canadien de Nature, Ottawa. 277
nalurel. la pp.
BoiviN, 1966. Enumeration desplanlcsdu Canada. Herbidees. Naluraliste
B.
III.
583-646.
can. 93:
Bouchard, D. Barabe, M. Dumais and Hay. 1983. Les planies vascu-
A., S.
laires rares du Quebec. Musee national des sciences naturelles, Ottawa. Syl-
logeus no 48. 79
pp.
New
Fernald, M. L. 1917. species, varieties and forms of Saxifraga. Rhodora
141-144.
19;
New
1950. Gray's Manual of Botany, 8th ed. American Book Co., York.
.
1632
pp.
&
HuLTEN, E. 1971. The Circumpolar Plants. Dicotyledons. Almqvist Wik-
II.
Stockholm. 463
sell, pp.
A
Kartesz, T. 1994. Synonymized Checklist of the Vascular Flora of the
J.
United Canada, and Greenland. Volume Thesaurus. Timber
States, Press,
2.
Portland, Oregon. 816
pp.
and
Krause, D. L. K. Beamish. 1973. Notes on Saxifraga occidentalis and
I.
Columbia. 105-1
closely related species in British Syesis 6: 13.
Lavoie, G. 1992. Plantes vasculaires susceptibles d'etre designees menacees ou
vulnerables au Quebec. Ministere de TEnvironnement. Quebec, Canada. 80
1
pp.
GQTvais al.—Saxifmga gaspensis 175
1995] ei
Rousseau, C. 1974. Geographic floristique du Quebec-Labrador. Distribution
des principales esp^ces vasculaires. Presses Univ. Laval, Quebec. 799
pp.
Museum
ScoGGAN, H. 1978. The of Canada, Part National of Natural
flora
J. 3.
Sciences, Publications in Botany 7(3): 547-1 115.
C. G., R. T.
RECHERCHE EN DE LA
SCIENCES
VIE
ET DE LA SANTE
MARCHAND
PAVILLON
C.-E.
LAVAL
UNIVERSITE
CANADA
QUEBEC, GIK
7P4
N. D.
DIRECTION DE LA RECHERCHE FORESTIERE
MINISTERE DES RESSOURCES NATURELLES
COMPLEXE
SCIENTIFIQUE
D-
1-100
RUE
EINSTEIN
2700,
CANADA
QUEBEC, GIP 3W8