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BFNA
Title: Thelia-Theliaceae |
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THELIACEAE
(Brotherus) M. Fleischer Bruce H. Allen Plants glaucous, bluish, yellowish-grey, or
dark-green, in dense mats. Stems creeping
or ascending, often densely tomentose, in cross section with small, firm- to
thick-walled epidermal cells, enlarged cortical cells, central strand
present; paraphyllia subfoliose or absent; pseudoparaphyllia filamentous or foliose-ciliate. Axillary hairs 3--6 cells long, basal cell subrectangular, reddish brown,
distal cells oblong, hyaline. Rhizoids
from clusters of initials abaxial to the leaf insertions. Leaves erect-appressed or imbricate
when dry, erect-swollen when wet, densely foliate, concave; stem and branch
leaves sometimes dimorphic. Sexual
condition phyllodioicous; dwarf males on tomentum or leaves of female
plants. Seta elongate. Capsule erect, stomata present;
peristome diplolepideous. Calyptra
cucullate, smooth, naked. Genera
1, species 3: North America, The
Theliaceae are small plants that occur in dense, often extensive mats. Their
single costate leaves have short, stoutly unipapillose leaf cells, and well
differentiated alar cells. Some members of the group have subfoliose
paraphyllia and some also have foliose-ciliate pseudoparaphyllia. They have
long setae; erect, more or less symmetric capsules; narrow exostome teeth
that are smooth at base, but otherwise papillose; rudimentary endostomes; and
cucullate calyptrae. There
has been considerable controversy over the systematic position of Thelia with the genus variously placed
in the Anomodontaceae, Hylocomiaceae, Leskeaceae, Theliaceae, or Thuidiaceae.
The disagreements are due to the classical moss dilemma: gametophytic
features that indicate one relationship, but sporophytic features pointing to
a different one. Thelia was revised
by H. A. Crum (1966); he noted the genus was gametophytically similar to the
Thuidiaceae, but had the sporophyte, especially the peristome structure, of Anomodon. He placed Thelia in the Thuidiaceae by the
differentiated stem leaves; polymorphous, ciliate paraphyllia; and stout,
curved papillae. W. R. Buck and D. H. Vitt (1986) placed Thelia in the Anomodontaceae on the basis of short leaf cells
with well-developed papillae, and narrow, white, papillose exostome teeth.
There is good molecular support (T.-Y. Chiang and B. A. Schaal 2000a, 2000b) for placing Thelia in the Hylocomiaceae. B.
Goffinet and W. R. Buck (2004) and B. Goffinet et al. (2009) placed Thelia in the monotypic Theliaceae due
to questions concerning the sample size of the molecular study. 1. THELIA Sullivant in A. Gray, Manual (ed. 2),
660. 1856. [Greek Thele, nipple, refers to the prominent leaf papillae
of the genus] Plants small to medium-sized. Stems with elongate surface cells,
1-pinnately or irregularly branched; branches erect-ascending, simple or
irregularly branched. Rhizoids
smooth, reddish brown, densely branched.
Leaves deltoid-ovate, broadly acute to obtuse, apiculate or piliferous,
decurrent; margins long-ciliate to ciliate below, ciliate-papillose above;
costae single, 1/2-- 3/4\x leaf length, sometimes spurred or forked, at times
double; cells rhombic to fusiform, stoutly 1-papillose abaxially, papillae
columnar, simple or 3--6 branched, alar cells quadrate or subrectangular. Seta smooth, flexuose when dry,
yellowish when young, red when mature. Capsule
cylindric to ovoid-cylindric, symmetric to somewhat curved, smooth to weakly wrinkled
when dry; exothecial cells at
mouth red, oblate to quadrate, proximally enlarged, quadrate to
short-rectangular; thin- to firm-walled; stomata on neck; operculum
conic-subulate; annulus rudimentary, of 2--3 layers of thin-walled cells,
persistent; exostome teeth white, linear, outer surface smooth at base,
finely papillose distally, trabeculae and median line thickened, inner
surface lightly papillose, trabeculae weak, teeth united at base on a short,
smooth membrane; endostome rudimentary, white, lightly papillose, basal
membrane low or high, segments reduced to stubs or reaching 1/2\x exostome
length, cilia 1--2, nub-like or absent. Spores
smooth to lightly papillose. Thelia is remarkable in its glaucous to bluish
green color, thick, densely tomentose mats, and tumid to julaceous stems and
branches. The stem leaves are distinctive by deltoid-ovate with rhombic
cells, simple or 3-6 branched, columnar papillae, and frequently long-ciliate
margins. The sporophyte has a long setae and typically erect, symmetric,
cylindrical to ovoid-cylindrical capsules. Its diplolepideous peristome is
yellowish-white with narrow exostome teeth that are smooth at base, but
otherwise papillose. The endostome is rudimentary with segments and cilia
often reduced to nub-like projections on a low or high basal membrane. In
the field, Thelia could be confused
with Myurella because both genera
have terete stems and branches that occur in mats or cushions, radiculose
stems, and a similar color. Myurella, however,
rarely occurs in dense mats, its leaves have short, double costae, serrate or
sinuous-dentate margins, and lower, unbranched papillae. 1. Leaf cell
papillae simple............................................................................. 2.
Thelia hirtella 1. Leaf cell
papillae with 3--6 branches at apex. 2. Stems creeping, densely, regularly
branched, often densely tomentose; branches evenly thickened, raggedly
imbricate, simple; branch leaves usually with spreading, piliferous apices.............................................................................................. 1.
Thelia asprella 2. Stems
often ascending, sparsely, irregularly branched, lightly tomentose; branches
clavate, smoothly imbricate, irregularly branched; branch leaves with erect,
apiculate apices.... 3. Thelia
lescurii 1. Thelia
asprella Sullivant in A. Gray, Manual (ed. 2), 660. 1856 E Leskea asprella Schimper in
P. Bruch, W. P. Schimper & W. Gümbel, Bryol. Eur. 5: 136. 1850 (fasc.
44--45); Hypnum hirtellum (Hedwig.) Müller Hal. var. furcatum Müller
Hal. Stems creeping, 1-pinnatedly branched,
branches erect-ascending, slender and terete, simple; paraphyllia not seen;
pseudoparaphyllia filamentous.
Stem and branch leaves more or
less similar, erect-appressed when dry, erect-swollen when wet, densely
foliate, 0.8--1 mm, broadly acute to obtuse, abruptly contracted to long,
clear, often spreading piliferous acumina, (occasionally long-apiculate),
decurrent; margins plane throughout, or plane distally and erect to somewhat
incurved basally, ciliate basally, ciliate-papillose distally; cells rhombic
nearly throughout, 12--20 x 8--12 \um, stoutly 1-1-papillose abaxially,
papillae usually 3--6 branched, oblong across the base, alar cells quadrate
or subrectangular. Seta 8--12 mm. Capsule symmetric to somewhat curved,
smooth to weakly wrinkled when dry, 2--2.5 mm; operculum 1--1.3 mm. Calyptra
2--3 mm. Spores 6--10 \um, smooth
to lightly papillose. tree trunks, rotting stumps, humus, and on
soil at base of trees, over rocks, or on ground; low to moderate elevations
(20--790 m); Ont., Que.; Ala., Ark., Conn., Del., Fla., Ga., Ill., Ind.,
Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., N.C.,
Nebr., N.H., N.J., N.Y., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Vt., Va.,
W.Va., Wis. Thelia asprella is a fairly small species that usually
grows in large, dense mats at the base of trees. --Thelia hirtella and T.
asprella are nearly identical in aspect; both species have terete,
regularly branched, densely radiculose stems, and piliferous leaves. Thelia hirtella differs from T. asprella most clearly in having
unbranched leaf cell papillae. In addition, the leaves in T. hirtella are dimorphic with stem
leaves much larger and more densely ciliate than the branch leaves. Thelia lescurii and T. asprella are similar in having leaf
cells with 3--6 branched papillae, but otherwise are quite different as noted
by the key characters. In addition, Thelia
lescurii is a larger plant than T.
asprella that nearly always grows on soil or over rocks. In the field T. lescurii can often be distinguished
from T. asprella because its
short-apiculate leaves give the plants a smoothly imbricate appearance. In T. asprella the piliferous apices are
often spreading and this gives the plants ragged appearance. 2.
Thelia hirtella (Hedwig) Sullivant in A. Gray, Manual
(ed. 2). 660. 1856 Pterigynandrum
hirtellum Hedwig, Sp.
Musc. Frond. 83. 1801. Stems creeping, 1-pinnatedly branched,
branches erect-ascending, slender and terete, simple; subfoliose paraphyllia
present; pseudoparaphyllia foliose-ciliate.
Stem and branch leaves dimorphic,
erect-appressed when dry, erect-swollen when wet, densely foliate. Stem leaves 1--1.3 mm, broadly acute,
sharply contracted to long, sometimes spreading, piliferous acumina,
decurrent; margins plane throughout, or plane distally and erect to somewhat
incurved basally, densely long-ciliate; cells rhombic to fusiform, 14--30 x
3--10 \um, stoutly 1-papillose abaxially, papillae simple, columnar and
curved, at base near the costa, smooth, elongate, and porose, oblong, smooth,
more or less porose across the base, alar cells quadrate or subrectangular. Branch leaves 0.6--0.9 mm; margins
dentate-toothed at base, sharply serrate distally; apical and median cells
rhombic, 14--20 x 3--8 \um, at base near the costa, smooth, fusiform,
sometimes porose. Seta 4--12 mm. Capsule erect, cylindric to
ovoid-cylindric, symmetric to somewhat curved, smooth to weakly wrinkled when
dry, 1--2 mm; operculum 0.8--1
mm. Calyptra 2--2.5 mm.Spores 12--16 \um, smooth to lightly
papillose. Tree
trunks, rotting stumps, humus, and soil usually at base of trees,
occasionally on rocks; low to medium elevation (0--1220 m); N.B., N.S., Ont.,
Ont., Que.; Ala., Ark., Conn., Del., Fla., Ga., Ill. Ind., Kans., Ky., La.,
Maine, Md., Mass., Mich., Miss., Mo., N.J., N.Y., N.C., Ohio, Okla., Pa.,
R.I., S.C., Tenn., Tex., Va., W. Va., Wis.; Mexico (Tamaulipas); West Indies
(Dominican Republic). Thelia
hirtella has the
broadest distribution of any Thelia species,
ranging from southern In
general aspect T. hirtella and T. asprella are very similar; both
have terete, regularly branched, densely tomentose stems, and piliferous
leaves. Often T. lescurii can be
distinguished from T. hirtella in
the field by branches clavate-shaped and smoothly imbricate. In contrast the
branches of T. hirtella have a somewhat
ragged appearance due to its often spreading, piliferous leaf apices. 3. Thelia lescurii
Sullivant in Gray, Manual (ed. 2),
660. 1856 E Thelia
asprella Sullivant in
Gray var. lescurii (Sullivant. in Gray) Habeeb Stems weakly creeping or crowded and
ascending, irregularly branched, branches also irregularly branched, primary
and secondary branches identical in form, erect-ascending, clavate;
paraphyllia not seen; pseudoparaphyllia foliose-ciliate. Stem
and branch leaves more or less
similar, imbricate when wet or dry, densely foliate, 0.8--1 mm, broadly acute
to obtuse, abruptly short-apiculate, decurrent; margins plane or erect to
incurved, stem leaf margins short-ciliate basally, branch leaf margins
ciliate-papillose; cells rhombic nearly throughout, 42--22 x 7--9 \um,
stoutly 1-papillose abaxially, papillae usually 3--6-branched, across the
base oblong, smooth, often porose, alar cells quadrate or subrectangular. Seta 8--17 mm. Capsule symmetric or somewhat inclined, smooth to weakly wrinkled
when dry, 1.5--3 mm; operculum
0.5--1 mm. Calyptra ca. 2 mm. Spores 10--16 \um, smooth to lightly
papillose. Sandy
soil, road banks, or soil over rock (granite, limestone or sandstone), rarely
at the base trees or on rotting logs; low to moderate elevations (50--513 m);
Ala., Ark., Del., Fla., Ga., Ill., Ind., Kans., Ky., La., Miss., Mo, Nebr.,
N.J., N.Y., N.C., Ohio, Okla., Pa., S.C.,
Tenn., Tex., Va., Wis. Thelia
lescurii is generally larger than the other species of Thelia and unlike
those species it almost always grows on soil or thin soil over rock. Plants
of T. lescurii have
mostly ascending, sparsely and
irregularly branched stems that are weakly tomentose because only those parts
of the stems in contact with the substrate have tomentum. The branches in T.
lescurii are thickened, often clavate-shaped, and irregularly branched.
This combination of features, along with its ascending stems, gives the
plants a compact aspect quite different from that of T. asprella or T.
hirtella. Thelia lescurii could be confused in the field
with Myurella because both occur on
calcareous soil, have a similar color, and smoothly terete stems and
branches. The leaves of Myurella,
however, have short, double costae and considerably lower leaf cell papillae. Literature cited. Buck, W. R. and D. H. Vitt. 1986.
Suggestions for a new familial classification of pleurocarpous mosses. Taxon
35: 21--60. Chiang, T.-Y. and B. A. Schaal. 2000a.
Molecular evolution of the atpB-rbcL
noncoding spacer of chloroplast DNA in the moss family Hylocomiaceae. Bot.
Bull. Acad. Sin. 41: 85--92. Chiang, T.-Y. and B. A. Schaal. 2000b.
The internal transcribed spacer 2 region of the nuclear ribosomal DNA and the
phylogeny of the moss family Hylocomiaceae. Pl. Syst. Evol. 224: 127--137. Crum, H. 1966. A taxonomic account of
the genus Thelia. Bull. Natl. Mus. Canada 216: 123--127. Fleischer, M. 1923. Die Musci der Flora
von Buitenzorg. Volume 4. Goffinet B. & W. R. Buck. 2004.
Systematics of Bryophyta (mosses): from molecules to a revised
classification. Monogr. Syst. Bot. Missouri Bot. Gard. 98: 205--239. Goffinet B., W. R. Buck and A. J. Shaw.
2009. Morphology, anatomy, and classification of the Bryophytes, pp. 55--138.
In: B. Goffinet & A. J. Shaw, Bryophyte
Biology. |
