Marattioid Ferns

Stems

Psaronius †

• Abundant in the Pennsylvanian

• Morphotaxon 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

• Morphotaxon for compressions of leaves of marattialean ferns during the Carboniferous

  • It is also the morphotaxon for some true ferns (Polypodiidae) and at least one seed fern (Taylor et al., 2009)

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

Scolecopteris †

• Watson, 1906

• Morphotaxon for permineralized leaves

Caulopteris †

• Morphotaxon for compression or impression petiole scars

Qasimia yunnanica †

• Fronds at least bipinnate. Pinnules taeniopteroid or neuropteroid, bases cordate, apices rounded. 

• Midvein distinct [andstraight]

• 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 pinnule margin.

• In fertile pinnules, lateral veins bifurcate once near midvein, 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.

• Sporangia  are 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