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BFNA Title: Scorpidium |
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Calliergonaceae - Scorpidium XX. SCORPIDIUM (Schimper) Limpricht, Laubm. Deutschl. 3: 570. 1899 * [Latin scorpio,
alluding to shoot apex like a scorpion tail] Lars Hedenäs Hypnum subg. Scorpidium
Schimper, Syn. 650.
1860; Limprichtia Loeske. Plants medium-sized to very robust, sometimes
turgid, green, brownish yellow, brownish to blackish red or red. Stem irregularly to pinnately branched ± in one plane, with weak central
strand (rarely lacking) and at least a partial outer hyalodermis,
cells inside cortex thin-walled; pseudoparaphyllia
broad; rhizoids or rhizoid initials on stem at or just before leaf
insertions; axillary hairs with 2--9(--11) distal
hyaline cells. Stem leaves from erecto-patent base suddenly curved in distal portion,
sometimes indistinctly so or ± straight, ovate-lanceolate
to broadly ovate (sometimes almost orbicular), with obtuse, apiculate, acute or acuminate apex, not or hardly
plicate, concave or strongly concave; margin finely denticulate or ± entire
near leaf apex, entire proximally; costa either
long and single, ending in distal half of leaf, or short and single or double
(rarely absent); median lamina cells thin-walled to strongly incrassate, eporose to porose;
differentiated alar cells 2--20, shortly to longly rectangular, thin-walled and hyaline, strongly
inflated, in small transversely triangular group, not or hardly decurrent. Sexual
condition dioicous
or autoicous; inner perichaetial
leaves plicate; vaginula with paraphyses.
Capsule curved and ± horizontal;
annulus separating; exostome reticulate or partly (rarely entirely) basally
cross-striolate externally, margin slightly dentate
distally. Spores 12--21 \um. Scorpidium species are characterized by a hyalodermis
of inflated, thin-walled epidermis cells, which is present in at least part
of the stem circumference. Unlike Hamatocaulis
species, they have at least a weak central strand in the stem, except in
very weak plants. They have small alar groups
consisting of a few (2--20) inflated and thin-walled cells that are sharply
delimited from the surrounding cells. Their stem leaves are normally smooth
and, like those of Hamatocaulis, from an
erect base suddenly curved above, except in most expressions of S. scorpioides. Although S. scorpioides
superficially looks very different from the other two members of the genus,
these differences are mainly found in characters, such as size and leaf
shape, that affect the appearance of the plant to the naked eye. On the other
hand, molecular evidence and critical microscopic features of, e.g., stems, alar cells, and exostomes
relate this species to S. cossonii and S.
revolvens. Based on molecular evidence, Scorpidium scorpioides
is an ingroup within S. cossonii, and is thus an example of
a species with a number of autapomorphies that are easily visible to the
naked eye, in a genus where the two other members have a more generalized
appearance. Scorpidium species are
found in mineral-rich to intermediately mineral-rich and normally
nutrient-poor habitats. When mineral-rich these habitats are mostly rich in
calcium. Species
3 (3 in the flora): widely distributed in the Holarctic
region, with scattered occurrences in more southern areas (also in the
southern hemisphere). SELECTED
REFERENCES Hedenäs, L. 1989. The genera Scorpidium and Hamatocaulis,
gen. nov., in 1.
Stem leaves strongly concave, almost orbicular and obtuse to apiculate, or from broadly ovate to broadly ovate-lanceolate base narrowed to apiculate,
acute or acuminate point, falcate or (rarely) straight; costa
usually double, more rarely single or lacking, rarely reaching above
mid-leaf; hyalodermis of stem often incomplete;
stem leaves ca. (0.7--)1--2.4 mm wide . . . 3.
Scorpidium scorpioides 1.
Stem leaves concave, from ovate to ovate-lanceolate
base narrowed to shortly to longly acuminate apex,
falcate; costa single, ending in upper half of
leaf; hyalodermis of stem complete; stem leaves ca.
0.5--1.1 mm wide. 2. Autoicous; mid-leaf cells 61--140(--179) \um, with
shortly to longly fusiform-narrowed
cell ends; outer peristomial layer usually
predominantly (more than 40--50%) cross-striolate
basally . . . 1. Scorpidium revolvens 2. Dioicous; mid-leaf cells of stem leaves 14--95(--120)
\um, with square to shortly fusiform-narrowed cell
ends; outer peristomial layer of exostome
predominantly (more than 70%) dotted basally. . . . 2. Scorpidium cossonii 1. Scorpidium revolvens (Swartz ex Anonymo) Rubers in A. Touw & W. V. Rubers, De Nederlandse Bladmossen 380. 1989 Hypnum revolvens Swartz ex Anonymo,
Monthl. Rev. 34: 538. 1801; Drepanocladus
revolvens (Swartz ex Anonymo)
Warnstorf; D. revolvens
var. miquelonensis (Renauld & Cardot) Grout; Limprichtia revolvens
(Swartz ex Anonymo) Loeske
Plants medium-sized to robust (sometimes when
submerged), not turgid, shoot apex not hooked, green, red, purplish red, dark
brownish red or blackish red. Stems sparsely
and irregularly or more rarely ± pinnately
branched, with well-developed, complete hyalodermis.
Stem leaves from erecto-patent or patent base ± suddenly curved distally,
ovate or ovate-lanceolate, gradually narrowed to
acuminate or longly acuminate apex, sometimes near
apex suddenly narrowed to apiculus, ca. 0.5--1 mm
wide, concave; costa single, ending in distal half
of leaf; median lamina cells (shorter half of leaf) 61--140(--179) \um, cell
ends shortly or longly fusiform-narrowed
(rarely rounded to almost square), differentiated alar
cells 2--10. Sexual condition autoicous. Peristome: proximal
outside of exostome predominantly (more than 40--50%) cross-striolate basally. More
or less common except in regions with strongly calcium-rich soils or bedrock
in the boreal and Arctic zones, farther south mainly in mountainous areas,
intermediately mineral-rich and often spring-influenced fens, small
periodically water-filled depressions, shores or, more rarely, submerged;
0-3020 m; Greenland; St. Pierre and Miquelon (Miquelon); Alta., B.C., Nfld., Man., N.W.T.,
Nunavut, Ont., Que., Sask., Yukon, Alaska, Colo., Idaho, Mich., Minn., Mont.,
Ohio, Vt., Wis., Wyo.; South America; Eurasia (including Papua New Guinea); s
Africa, Pacific Islands (New Zealand); Antarctic. This
species has often been confused with S. cossonii,
and the differences between these species are discussed under the latter. 2. Scorpidium
cossonii (Schimper) Hedenäs, Lindbergia 15: 18. 1989 Hypnum cossonii Schimper,
Musci Eur. Nov. Bryol. Eur. Suppl. fasc. 3--4 (Mon.): 5, 5.
1866; Limprichtia cossonii
(Schimper) L. E. Anderson, H. A. Crum & W.
R. Buck; Drepanocladus intermedius (Lindberg) Warnstorf;
D. revolvens subsp.
intermedius (Lindberg) Grout; D. revolvens var. intermedius
(Lindberg) L. R. Wilson Plants medium-sized to robust (sometimes when
submerged), rarely slender, not turgid, shoot apex sometimes slightly hooked,
green, yellow-green, brown or brown-red. Stems
pinnately or sometimes irregularly branched,
with well-developed, complete hyalodermis. Stem leaves from erecto-patent
or patent base ± suddenly curved distally, ovate or rather broadly ovate,
gradually narrowed to shortly or longly acuminate
apex, near apex often suddenly narrowed to apiculus,
ca. 0.5--1.1 mm wide, concave; costa single, ending
in upper half of leaf; median lamina cells (shorter half of leaf)
14--95(--120) \um long, cell ends square, rounded or shortly fusiformly narrowed, differentiated alar
cells 2--10(--15). Sexual condition dioicous. Peristome: lower
exostome outside predominantly (more than 70%) dotted basally. Common
in regions with calcium-rich soils or bedrock in the boreal and Arctic zones,
farther south mainly in mountainous areas, ± calcium-rich habitats in fens,
springs, periodically water-filled depressions, shores or, more rarely,
submerged; 0-3650 m; Greenland; Alta., B.C., Man., Nfld., N.W.T.,
Nunavut, N.S., Ont., Que., Sask., Yukon; Alaska,
Colo., Conn., Ill., Iowa, Maine, Mich., Minn., Mont., N.J., N.Y., Ohio, Vt.,
Wis.; South America, Eurasia, Pacific Islands (New Zealand). Scorpidium cossonii is often confused with S. revolvens or Hamatocaulis
vernicosus. From the latter it is easily
separated by its hyalodermis and the usually
present central strand of the stem, and by its differentiated hyaline and
inflated alar cells of the stem leaves. Hamatocaulis vernicosus,
which lacks all these features, usually has distinctly plicate stem
leaves, whereas these are smooth in S. cossonii.
Scorpidium cossonii
differs from S. revolvens in being dioicous (the latter is autoicous)
and in having shorter mid-leaf cells in the stem leaves. The ends of these
cells are square to shortly fusiform-narrowed in
the first species whereas they are shortly to longly
fusiform-narrowed in the latter. Both species may
have red or strongly red colors, and in such cases S. cossonii
is usually brownish red while S. revolvens is
mostly blackish or purplish red. Due to a large variation in both species,
especially when herbarium material is also considered, color should, however,
be used with care in identifying specimens. Dark purplish plants usually
belong to S. revolvens and predominantly
green or yellow-green plants with a brown-red costa
or costa and leaf base belong to S. cossonii. The differences in leaf areolation between
the two species make S. cossonii less glossy
than S. revolvens, but this character, like
the difference in size and branching pattern (S. cossonii
is slightly smaller and more richly and regularly branched than S. revolvens), which is obvious in mixed collections, is
often difficult to use in identification without much experience. In mixed
collections S. cossonii has more shortly
acuminate stem leaves than S. revolvens, but
both species are variable in this character and the overlap between them is
great. 3. Scorpidium scorpioides (Hedwig) Limpricht, Laubm. Deutschl. 3: 571. 1899 Hypnum scorpioides Hedwig, Sp. Musc.,
295. 1801 Plants robust or very robust, occasionally
medium-sized, turgid plants, often with a characteristic claw-like shoot
apex, green, brown or often red to blackish red. Stems mostly sparsely or irregularly pinnately
branched, with partial or complete hyalodermis
(more than 25% of stem circumference). Stem
leaves from erecto-patent to patent base
usually rather suddenly curved distally, rarely straight or almost so,
varying in shape from almost orbicular to broadly ovate-lanceolate,
suddenly narrowed to obtuse and mostly apiculate
point or more gradually narrowed to acute or acuminate point, ca.
(0.7--)1--2.4 mm wide, strongly concave; costa
double or occasionally single (rarely absent), reaching somewhere below to
very rarely slightly beyond middle of leaf, when single often branched;
median lamina cells (shorter half of leaf) 32--200(--210) \um, cell ends
square, rounded or shortly fusiformly narrowed,
differentiated alar cells 5--20. Sexual condition dioicous.
Peristome: proximal outside of exostome
varying from almost entirely cross-striolate to
almost entirely dotted. Common
in many areas in the north, and in the Arctic, rich or intermediate habitats
in fens, pools, lake shores or submerged in lakes; 0--3550 m; Greenland;
Alta., B.C., Nfld., Man., N.B., Nfld., N.W.T.,
Nunavut, N.S., Ont., Que., Yukon; Alaska, Colo.,
Conn., Ind., Maine, Mich., Minn., Mont., Utah, Vt., Wis., Wyo.; South America;
Eurasia; Australia. Scorpidium scorpioides is usually easily known by its large
size and strongly concave, broad and usually shortly pointed leaves with a
short single or double costa. Straight-leaved
phenotypes, which are rare, look very different from the falcate-leaved ones,
but, except for the leaf curvature, there does not seem to be any difference
between these phenotypes. Specimens with straight leaves could be confused
with Pseudocalliergon turgescens
and the differences between the two are given under the latter. |
