Detailed Description: Frullania truncata
Species Description:
Plants small (main shoots 350-550 µm wide), forming olive-green,
copper-brown, to black patches, closely to loosely adhering to substrate.
Branching sparingly, usually irregularly pinnate to rarely bipinnate.
Dimorphic branching, with both Frullania-type (FB) and occasionally,
Lejeunea-type (LB) branching. Initial appendages of FB: First branch underleaf
(BUL1) always with three distinct segments, the ventral lamina divided
for ½ its length into two subequally sized lobes + 1 dorsal lobe which is
either saccate, sulcate or explanate. First branch leaf (BL1) varies,
either: reduced in size, ventral segment elobulate, and explanate to sulcate,
with leaves characteristic of the main stem starting at BL2-BL3 (BL4); or
the appendages of BL1 ± characteristic of normal stem leaves (i.e.BL1: 1 explanate
dorsal lobe + 1 saccate lobule + 1 stylus). Initial appendages of LB: BUL1
and BL1-3 are always reduced in size and lobule-free, formation of normal
lobulate leaves occurring thereafter. Lobules ± remote from the stem (lobule
attached to stem by 2-3 cells) and at angles of 30-50 (60)° with the stem
so that lobules tilted outwards; lobules similar in colour to other organs;
cylindrically pitcher-shaped (orbicular in cross-section with up to 20 cells
in circumference), its area obscuring no more than 0.25 × the exposed area
of the dorsal lobe), and 1-1.75 (2) × long as wide, 100-140 µm long × 60-90
µm wide, somewhat dorsiventrally compressed near mouth as compared to slightly
gibbous upper half, the opening wide, extending along the abaxial lobule margin;
ca. 1/3 from lobule mouth there is usually an enlarged and elongated cell,
cell cavity to 12.5 µm long × 7.5 µm wide, to1.5-3 × long as wide), the free
wall forming a protuberance that projects outwards to 5 µm; the free margin
of the lobular mouth inconspicuously crenulate-sinuate, hyaline only at marginal
cells of the mouth, lobule apex obtuse. Stylus large, to almost 0.5 the length
of the lobule, subrectangular in outline, up to 70 µm long × 45 µm long, 4-5
(6) cells wide at base × 6-7 cells long, (10) 14-25 (30) cells in total, occasionally
with a slime papilla at apex. Underleaves of leading stems 1/4 to 1/3 the
size of leaf lobes, distant from lobules, underleaves usually distant or occasionally
contiguous to each other, usually longer than wide, 1.25-1.5 × the stem in
width, to 100 µm long × 75 µm wide; broadest at 1-2 cells below sinus at which
point the underleaf is (5) 6-7 (8) cells wide; free lateral margins always
entire; apex of underleaf bilobed to ½ its length, lobes separated by a narrowly
U to V-shaped sinus, lobes with 3-4 cells wide at base and acute to subacute
apices. Lobe marginal cells ± rectangular, hyaline walls subequally thickened,
cell cavities brownish red, to 7 µm long × 5 µm wide. Median cells usually
± uniform in shape and size; ± subquadrate to rectangular, walls usually 4-5
sided, hyaline walls heavily and equally thickened, intermediate thickening
absent, wall thickness to 2.75 µm wide; cell cavities of median cells brownish
red, (7) 9-14 (16) µm long × (6) 7-11 (13) µm wide (1-1.5 × long as wide);
cells becoming gradually larger basally, cavities of the basal median group
of cells to 15 µm long × 12 µm wide; walls of basal cells with slightly convex
trigones and occasional intermediate thickenings, walls and cavities brownish
red. Oil-bodies of the leaf lobe median cells: 2-3 (4) oil-bodies per cell,
typically small, spherical (1) 2-3 (4) µm in diam. to ovoid or ellipsoidal
(2) 2-3 (5) × (1) 1-2 (3) µm, subhyaline, without any significant, visible,
internal structure i.e giving the appearance of being almost homogeneous.
The oil-bodies are often similar in size to or slightly smaller than the chloroplasts;
occasionally the oilboides are larger than the chloroplasts. The oil-bodies
of the lobule and underleaf are similar to those encountered in the leaf lobe.
Oil-bodies becoming progressively larger towards the basal cells and coarsely
granular, usually 3-5 per cell, ocelli never present. Asexual reproduction;
none known. Plants dioecious. Androecia subspherical to discoid, 2-4 pairs
of bracts, sessile on a leafless stalk or terminal on short-stalked branches
(stalk with 1-4 vegetative leaf lobes). Gynoecia terminal on main or leading
stem. A shoot system often occurring between bracts and perianth (subfloral
innovation) or arising 2 complete leaf cycles below the gynoecia or perianth
bracts i.e. a subfloral branch. ? bracts and bracteoles in 1-2 closely imbricate
cycles. Margins of bract-lobes, bract-lobules and bracteoles entire. Innermost
bract unequally bilobed; bract-lobe ovate to oblong, gradually tapering to
a truncate to rounded apex, bract-lobule ovate-lanceolate, subacute apex;
innermost bracteole free from bracts, oblong in outline with subparallel margins,
about 1¤3-1¤2 bilobed, the sinus broadly V-shaped, lobes with acute to subacute
apices. Marginal and median cells of bract and bracteole ± subequally thickened.
One archegonium per gynoecium. Perianth freely emergent, to 700 µm long (excluding
the perianth beak) × 450 µm wide, exterior smoothly trigonous, oblong-ovate,
tapering towards the apex into a short beak; perianth beak cylindrical, to
60 µm long, rim of the mouth smooth but the inner beak surface densely covered
with large single-celled protuberances. Sporophyte: not seen.