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BFNA Title: Mylia |
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Jungermanniaceae - Mylia XXX. MYLIA Gray, Nat. Arr. Brit. Pl. 1:693, 1821, as Mylius
· [named for Willem Mylius, a Dutch physician] Marie L. Hicks Plants simple or sparingly branched, prostrate or decumbent
with ascending apices when crowded, forming loose mats or thick tufts, green
to reddish brown. Stems rather fleshy, 450‑‑600 µm in
diameter; branching mostly terminal or lateral and axillary; cortical and
medullary cells not distinctly differentiated; rhizoids scattered over
ventral stem surface, long, often dense, especially at leaf and underleaf
bases. Leaves succubous‑oblique, alternate, circular to ovate in
outline; leaf cells irregularly hexagonal, large, ca. 45‑‑55 µm in diameter,
with large, bulging trigones and thin intervening walls; oil bodies granular‑botryoidal,
opaque, or hyaline. Underleaves present, lanceolate. Specialized
asexual propagation by gemmae on leaf margins, ovate to elliptical, 1‑‑2-celled. Sexual
condition dioecious. Androecia intercalary;
bracts imbricate, similar to leaves, with saccate base; antheridia 1‑‑3 per
bract with large jacket cells; stalk 1‑seriate, long. Gynoecia
terminal on main shoot; bracts sub‑orbicular, entire, larger than leaves,
partially enclosing the perianth; bracteole present, lanceolate; perianth
exerted about 1/4‑‑1/2 above bracts, inflated, laterally compressed, the
mouth wide, truncate, entire to ciliate; perigynium not present. Seta
ca. 9‑‑11 cells in diameter. Capsule
short ovoid, 4‑valved; walls 3‑‑5 cells thick, exterior layer with
thickenings that extend inward, the interior layers with semiannular
thickenings; elaters 120‑‑160 ´ 8‑‑10 µm, 2‑spiral. Spores 15‑‑20 µm. Species 4 (2 in the flora): North America, Europe and
Asia. SELECTED REFERENCES Schuster,
R.M. 1969. The Hepaticae and
Anthocerotae of North America. New York. 1. Distal
leaves on gemmiparous shoots longer than wide, with subacute apices; gemmae
green; cuticle smooth . . . . 1. Mylia
anomala 1. Distal
leaves on gemmiparous shoots wider than long, with rounded apices; gemmae
brownish; cuticle rough, fissured . . . . 2. Mylia taylori 1. Mylia anomala (Hooker) Gray, Nat. Arr. Brit. Pl. 1: 693. 1821 Jungermannia anomala Hooker, Brit. Jungerm. pl. 34. 1813 Plants with shoots 20‑‑30 ´ 2.4‑‑3 mm, prostrate, forming mats over peat or
occurring as stems intermingled with moss, pure green to yellowish or reddish
brown. Stems ca. 10‑‑12 cells in diameter, branches few, most arising
beneath perianths; cortical cells 28‑‑35 µm in diameter, slightly smaller
than medullary (32‑‑42 µm); interior cells with small trigones. Leaves contiguous to imbricate,
spreading to erect, orbicular to ovate, ca. 1400 ´
1450 µm, narrowed at the insertion, concave; leaves on gemmiparous shoots
progressively narrower toward stem apex, becoming lanceolate (ca. 1400‑‑1500 ´
1100‑‑1150 µm) with subacute apex; median leaf cells large, 50‑‑60 ´
45‑‑50 µm, basal cells larger, 50‑‑55 ´ 65‑‑75 µm; cuticle smooth; trigones large, bulging,
knotlike; oil bodies 6‑‑18 per cell, ovoid, 7‑‑8 ´
5‑‑7 µm, granular‑botryoidal with protruding globules, hyaline. Underleaves
distinct, lanceolate, large (to 500‑‑600 µm), often hidden among
rhizoids. Specialized asexual propagation by gemmae, often present on
distal lanceolate leaf margins, spherical to elliptical, 30‑‑40 ´
45‑‑50 µm, 2‑celled, green. Androecia intercalary; bracts 4‑‑7
pairs, entire, ovate with saccate base, antheridia 1‑‑2 per bract. Gynoecia
terminal on main shoot; bracts similar to leaves, larger, somewhat
recurved; bracteole large, lanceolate; perianth inflated, compressed
laterally, exerted above bracts about 1/2 its length; mouth 2-labiate, entire
to slightly crenulate. Peat bogs or on moist peaty soil over outcrops, Arctic‑alpine;
s, sw and w Greenland; Alta, B.C., Nfld., N.W.T., N.S., Ont., Que., Yukon;
Alaska, Conn., Maine, Mich., Minn., N.H., N.J., N.Y., Pa., Wash., W.Va.,
Wis.; n Europe; e Asia. Commonly found in northern Sphagnum bogs, this species occurs as far south as the Cranberry
Glades of West Virginia. 2. Mylia taylori (Hooker) Gray, Nat. Arr. Brit. Pl. 1:693. 1821 Jungermannia taylori Hooker, Brit. Jung. pl. 57. 1813 Plants large, with shoots 30‑‑80 ´
3‑‑3.6 mm, decumbent to ascending when crowded, forming thick mats or tufts,
green to reddish or purplish brown. Stems 480‑‑550 µm in diameter, simple
or sparingly branched with terminal branches; cortical cells 28‑‑40, thin‑walled,
medullary cells 32‑‑40 with small trigones.
Leaves succubous‑oblique,
spreading, imbricate, orbicular to broadly ovate, 1.5‑‑2 ´
1.8‑‑2.4 mm, slightly concave at the base, convex distally or with deflexed
margins; leaf cells large, median cells 45‑‑60 ´ 40‑‑45 µm, smaller along margins, ca. 35‑‑45 µm;
cuticle rough, finely fissured forming plates; trigones large and bulging,
knotlike; oil bodies 7‑‑12 per cell, ellipsoidal, large, 15‑‑18 ´
8‑‑10 µm, coarsely granular, opaque, brownish‑gray, partially obscuring the
cell lumen. Underleaves distinct, subulate to lanceolate, up to 0.5 mm,
hidden among rhizoids. Specialized asexual propagation frequent,
by gemmae on margins of broadly ovate distal leaves, elliptical to ovate, 25‑‑30
´
40‑‑45 µm, 1‑‑2 celled, brownish. Androecia intercalary; bracts 4‑‑8
pairs, imbricate, similar to leaves with saccate base; antheridia 2‑‑3 per
bract. Gynoecia terminal on main stem, often with 1‑‑2 subfloral
innovations; bracts entire, similar to and slightly larger than leaves, ca. 2
´
2.2 mm; bracteole lanceolate, large, to 0.7 mm; perianth partially hidden by
bracts, exerted ca. 1/2 its length, laterally compressed, the mouth
contracted, ciliate, the cilia 4‑‑6 cells long. Moist mountains on humus over outcrops and in rocky
crevices with at least a small accumulation of peat; s Greenland; B.C.,
Nfld., N.S.; Alaska, Maine, N.H., N.Y., N.C., Tenn., Wash.; Europe; eAsia. |
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