BFNA Title: Pallaviciniaceae |
XX. PALLAVICINIACEAE Migula Vadim Bakalin Plants terrestrial,
bright green. Thallus unlobed,
unistratose except for a sharply well-defined, cordlike midrib, branching
dichotomous and latero-ventral, with a well-defined central strand of narrow
conducting cells, underside without scales, without Nostoc colonies. Specialized asexual reproduction
absent. Sexual condition dioecious,
gametangia dorsal on main thallus segments, antheridia subtended by small
unistratose scales, archegonia clustered, each cluster surrounded by a ring
of partially fused scales forming an involucre. Sporophyte protected by a long, cylindrical pseudoperianth
surrounding an enlarged calyptra. Capsule
cylindric, 2(--4)-valved, without fixed elaters. Spores unicellular when shed, their walls rather thin and
delicate. Genera 8 (1 in
the flora): North America, Central America, South America, Europe, se Asia,
Africa. XX. PALLAVICINIA
Gray Nat. Arr.
Brit. Pl. 1: 775. 1821* [Probably for Lazarus Opizio Pallavicini,
fl. 1719--1785, botanist and archbishop of Blyttia Endlicher Plants 15--60 mm x 2--8
mm, translucent-green to deep green, without other pigments, with only old
portion of thalli becoming brownish green or
decolorate. Thallus branching
latero-ventral, rarely furcate, thallus flattened, margin plane or lightly
undulate, with well-defined biconvex costa, mostly with clearly visible
(whitish or yellowish brownish) single median vascular strand; shoot apices
ventrally with 2--3--celled slime papillae. Rhizoids brownish, distributed along ventral surface of costa. Thallus margin entire (except for
mostly ephemeral 1(--3)-celled teeth or slime papillae) [dentate]. Thallus lamina 1 cell in thickness,
laminar cells thin-walled, polygonal; along margin dentate-ciliate to
virtually entire. Asexual reproduction
absent. Sexual condition dioicous.
Androecia dorsal; antheridia
in one row on each side of midrib [irregularly scattered over midrib], each
subtended by a laciniate-dentate
scale. Gynoecia
solitary on dorsal side of costa, outer involucre of complete ring of
laciniform scales, free or united proximally; capsule surrounded by a tubular
pseudoperianth. Seta 17--24 mm. Capsule wall 2-stratose. Spores 17--24 \um, areolate to
papillose. Elaters ca. 150--350 x
7--9 \um, 2(--3)-spiral. Species
ca. 30 (1 in the flora): North America, Central America, South America,
Eurasia, SELECTED REFERENCE Doyle, W. T. and R. E. Stotler. 2006 Contribution toward a bryoflora of California III. Keys and Annotated species Catalogue for Liverworts and Hornworts. Madroño. 53: 89--197. 1. Pallavicinia lyellii (Hooker) Gray, Jungermannia lyellii Hooker,
Brit.
Jungermann., pl. 77. 1816; Blyttia lyellii (Hooker) Endlicher ex Gottsche,
Lindenberg & Nees Plants 15--50 x 2--6 mm.
Thallus with lightly undulate
margin, with clearly visible (whitish or yellowish brownish) single median
vascular strand. Thallus margin
mostly entire except for regularly spaced ephemeral 1(--3)-celled teeth or
slime papillae (quickly disintegrating in herbarium or in old portions of
thallus). Thallus lamina with
cells thin-walled, 35--100 x 24--48 \um, cells slightly elongated along
margin. Oil-bodies small and
numerous, in middle part of lamina 30--65 per cell, spherical to ellipsoidal,
fusiform, botryoidal to granulate, small 2--6 x 2--4 \um to larger 8--11 x
2--5 \um. Androecia with antheridia and
scales in one row on each side of midrib; antheridial body spherical to
shortly ellipsoidal. Gynoecia with
outer involucre 1.5--2 \um high in maturity, consisting of ciliate-laciniate
segments; inner involucre (pseudoperianth) tubular, 5--8 mm high,
ciliate-laciniate at mouth. Seta
17--24 mm. Spores 17--24 \um,
areolate. Elaters 2--3-spiral. Wet
and shady places along banks of ponds, stream, lakes, or in swamps associated
with flowing water, only in acidic habitats; low to moderate elevations; N.B., Nfld. and Labr. (Nfld.), N.S., Ont.; Ala., Ark., Calif., Conn., D.C., Fla., Ga., Ill., Ind., Ky., La., Maine, Md., Mass., Mich., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tenn., Tex., Vt., Va., W.Va.; Central America: South America;
Eurasia: Africa; Pacific Islands; Australia. |