Marattioid Ferns

Stems

Psaronius †

• Abundant in the Pennsylvanian

• Form taxon for the trunk, which may have been up to eight to ten meters in length

  • The stem possessed a dictyostele with endarch maturation xylem

• P. simplicicaulis (Dimichele & Phillips 1977)

  • One of the earliest marattialean ferns from the Early Pennsylvanian of North America

• P. renaultii (Williamson 1876)

Leaves

• The ferns possessed a large crown of pinnately-compound leaves inserted in spirals or vertical rows on the trunk

• The fronds were large, up to three meters in length, bilaterally symmetrical, and planate

• The petioles have a U-shaped vascular trace

Pecopteris

• Devonian - Carboniferous, with the greatest diversity in the Pennsylvanian

• Form genus for compressions of leaves of marattialean ferns during the Carboniferous

  • It is also the form genus for some true ferns (Polypodiidae) and a least one seed fern (Taylor et al. 2009)

• There are over 250 species of Pecopteris named (Robertson & DiMichele 1997)

Scolecopteris

• Watson 1906

• Form genus for permineralized leaves

Caulopteris

• Form genus for compression or impression petiole scars

Qasimia yunnanica †

• Fronds at least bipinnate. Pinnules taeniopteroid or

• neuropteroid, bases cordate, apices rounded. Midvein distinct [and

• straight]. Lateral veins curved, rising at an acute angle, perpendicular

• or subperpendicular to pinnule margin. In vegetative pinnules, lateral

• veins commonly bifurcate twice, occasionally three times, showing

• first bifurcation near the midvein, with a vein density of 40–50 veins

• per centimeter at the pinnulemargin. In fertile pinnules, lateral veins bifurcate

• once nearmidvein,with vein density less than half of vegetative

• pinnules. Fertile pinnules identical in size and shape to vegetative pinnules.

• Synangia, as pendants, abaxially attached, [arranged in one row

• on each side of midvein], born on every individual lateral vein branch,

• closely spaced, with length of nearly half-width of pinnules, and in a

• ‘louvered’ pattern [or an imbricate arrangement]. Each valve of

• bivalvate synangia composed of elongated and laterally fused sporangia.

• [Sporangial number per valve varyingwith synangiumlength, up to 40.]

• Sporangia [long ellipsoid, exannulate, with length near synangium

Roots

• Abundant roots that are large and fleshy, completely encasing the stem forming a root mantle

• The root cross-section reveals an exarch actinostele

• The roots that are closest to the stem have a thick, sclerenchymatous cortex, and reinforced the trunk which lacked secondary xylem

Reproduction

• Spore-bearing

• Fertile fronds bore synangia composed of eusporangia on the abaxial surface, commonly clustered near veins of ultimate pinnules

• Sporangia have uniform dehiscence along the midline of the sporangia

• Spore genera Punctatisporites and Laevigatosporites are associated with Pecopteris foliage