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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. |
