Szea

Name

Szea

Rank

Genus

Authors (Pub.)

Yao Z.-Q. Taylor T. N.  

Publication

On a new gleicheniaceous fern from the Permian of South China [1988/2]

Journal

Review of Palaeobotany and Palynology

Volume

54

Issue

1-2

Page number

123

Year

1988

Parent Taxon

[Class] Gleicheniopsida

Fossil Status

foliage (fertile)

Type

Szea sinensis

Diagnosis

Frond at least bipinnate, rachis stout, smooth; impression showing a marked contrast between a median groove and flat, narrow wing-like flanks. Pinnae widely separated, opposite to alternate, lanceolate to linear, pinna rachis thin, with groove on adaxial surface; pinnae attached at an angle of 50 70 °. Pinnules of the cladophleboid-type, linear to triangular, falcate, and attached along entire base; base decurrent and fused to adjacent pinnules, margin crenate or serrate in the basal portion of the frond and pinnae, becoming gradually entire in the distal portion of the frond and at the apex of the pinnules; pinnule apex variable, typically obtuse in proximal region of frond and pinnae, acute toward apex of frond and pinnae. Catadromous pinnules near the proximal portion of the pinna usually shorter, with small deltoid basal pinnule, lobed on the catadrome side; basal anadrome pinnules typically larger than others and arranged nearly parallel to main rachis; pin- 123 nule midvein distinct, extending nearly to apex, secondary veins sympodially dichotomous 2-3 times, simple near apex, veinlets from secondary vein arranged in fascicles, each extending into a tooth or lobe of the pinnule margin. Sori arranged in two rows, each between the margin and midvein of the pinnule, 1-8 (usually 5-6) in each row, sori arranged on the distal branch of each fascicle of the secondary vein, except basal anadromous fascicle of pinnule that may bear two sori on both proximal and distal branches of fascicle, former always located nearer the margin; sori round to oval, consisting of 20 30 sporangia, indusium lacking and attached to convex receptacle. Sporangia oval, annulus entire, transverse and consisting of one row of elongate cells; annulus encircles upper-middle part of sporangium except where interrupted by stomium. Each sporangium with 108 216 trilete spores, each 40 68pm; spores with triangular amb, interradial area straight to concave, radial areas rounded to truncate, trilete distinct with laesurae extending to auriculae, exine ornamented with irregular grana or verrucae often with a broad base, auriculae 3 5#m thick, wavy or slightly folded; sporoderm homogeneous, 2-3 pm thick and lacking distinct layers.