re-evaluation of tortella - Missouri Botanical Garden

in the lamina, the var. fragilifolia is usually broken at
the leaf tip.
Dixon (1924) was also not sure of the
distinction of Tortella fragilis from T. tortuosa. He
would have liked to have been definite but, "I have,
however, received specimens from two or three
localities in Labrador showing a distinct approach to [T.
tortuosa]; the leaves on some of the plants, and even the
lower leaves on some stems in which the distal ones are
quite typical, being strongly contorted when dry, crisped
and undulate at the margin, and when moist slightly
flexuose and undulate; hardly, indeed, to be recognised
from the var. fragilifolia...except by the leaves
somewhat firmer, the very shining nerve and the
presence (usually) of some rigid and less curved
leaves." He speculated that T. fragilis would be found to
be close to T. tortuosa "by intermediate forms."
Polunin (1947), when reporting Tortella
fragilis for the Canadian Eastern Arctic, quoted the
same lines from Dixon (1924), adding "This puzzling
situation that Mr. Dixon has so ably elucidated is to be
found also in the specimens from Baffin Island"
although some of these specimens, upon examination,
may turn out to be T. tortuosa var. arctica.
Tortella tortuosa var. fragilifolia in North
America appears to be a montane and boreal taxon. The
var. fragilifolia in North America is apparently not in
montane elevations much south of the latitude of the
Canadian border with the conterminous United States.
TORTELLA NITIDA IN NORTH AMERICA
Sources of North American reports of Tortella nitida
perhaps began with Renauld and Cardot (1889: 99) (as
Trichostomum nitidum) "United States, without locality,
collected by James, communicated by Mr. Bescherelle."
Barnes (1897: 275–276) next reported the
species, quoting Renauld and Cardot and basing his
description on Limpricht (1890, 1: 581) where the
description of the proximal cells indicates their being
"less sharply marked off from chlorophyllose cells."
Assuming James, of the Renauld and Cardot quote, to
be Thomas Potts James (1803–1882), a request was
made to the Farlow Herbarium for a specimen that
might correspond, but without success. A James
specimen at NY collected by him in Canada, July 1850,
was Tortella tortuosa var. tortuosa.
Next, there is the exsiccat specimen in the
Canadian Musci by John Macoun, number 605, labeled
as Barbula nitida. In 1892, Macoun and N. C. Kindberg
published the label data (number 196, p. 52). Kindberg
(1897) affirmed its occurrence ("Can.: Macoun.),
presumably from Macoun's exsiccat number 605.
Macoun 605 is labeled as Barbula nitidum [sic] (Lindb.)
Jur., of the Canadian Musci series, "on wet earth at
Hector, Rocky Mountains, B.C. [British Columbia,
Canada], Aug. 14th, 1890" and is Tortella tortuosa var.
fragilifolia (one specimen at FH, two others at NY). It is
as tall as the typical variety gets, has a broad stem
section but no central strand. Some apices are deciduous
and there is conspicuous fragility of the lamina. The
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crucial juxtacostal bistratose character of the leaf
cross section is present. The cells of the lamina are
unusual for the species, on some leaves regularly ca. 14
µm, some even to 17 µm in diameter, with distal
proximal cells thick-walled and porose. Some leaves on
the same stem have adaxial quadrate cells covering the
costa nearly to the apex, in others the adaxial surface of
the costa is exposed in a narrow groove from base to
apex.
Subsequent reports of Tortella nitida include
Haring's (1938) treatment in Grout's moss flora of North
America, Flower's treatment for the state of Utah
(1973), Ketchledge's publication on the moss flora of
New York State (1957), Steere and Scotter's (1978)
report for the Nahanni Preserve, in the Mackenzie
District of the Northwest Territories, and the recent
checklist of Canadian mosses (Ireland et al. 1987).
Haring (1938) cited Macoun's number 605 in
the Canadian Musci as Tortella nitida; also a specimen
from Montana in NY, and one by Homer House, a
specimen from Harris Lake, New York. Haring and
perhaps Grout, were strongly influenced in their
expectations by the Macoun specimen. This was at a
time when it was not yet accepted that some of Macoun
and Kindberg's determinations were perhaps doubtful.
Kindberg's determinations of Macoun's specimens
"were often hasty and consequently wrong and
Macoun's own determinations were often based on
superficial study and thus are open to doubt" (Schofield
1965), and yet Bescherelle and Dixon also made similar
independent determinations.
Examination of the specimen of Tortella nitida
that Haring cited for Lake Harris (New York, Essex Co.,
Newcomb, surface of boulder on shore (perichaetiate:
without sporophytes), July 10, 1927, H.D.House (NYS),
shows this specimen also to be Tortella tortuosa var.
fragilifolia. The Harris Lake specimen was fragile in
some stems, but on the whole seems more typical of T.
tortuosa than most examples of the variety fragilifolia
(it had no stem central strand). The leaves on some
stems, however, were more broadly lanceolate with
larger distal laminal cells (to 12 µm). Some of the leaf
cross sections showed some bistratose areas near the
costa in the distal median portion of the leaf.
The Harris Lake specimen showed no
annotation by Haring or Grout. There was a query on
the label, and the note, "Doubtful !E.H.K" [Edwin H.
Ketchledge] written on the packet. Ketchledge's
subsequent publication on the moss flora of New York
State (1957) listed Tortella nitida for the New York
flora, but in the revised edition (Ketchledge 1980), there
was no citation of that species.
Another specimen of the var. fragilifolia, from
New York on limestone pavement in Jefferson Co. in
association with Tortella rigens, is cited below in the
treatment of that species.
Haring's third representative specimen was
from Montana at NY. A specimen from Montana
collected by R. S. Williams, 329 at NY was determined
here to be Tortella alpicola (see discussion of this