Pseudosporochnales †

Duisbergia †

• Emberger; Taylor et al. 2009)

• Characterized by "small, wedged-shaped leaves lacking leaf cushions" (Taylor, Taylor, & Krings 2009)

D. mirabilis

• Kräusel & Weyland 1929

• Middle Devonian

• Upright, unbranched stem reconstructed to 2 m height, with a club-shaped base

• Dense crown of leaves, which are arranged in a tight spiral on the top of the stem

• The leaves are arranged in vertical rows

• The distal axes consist of fan-shaped leaves (5 cm long)

• Well-preserved specimens have up to 60 xylem lobes with secondary xylem arranged in a ring

D. macrociccatricosus 

• Mustafa 1978; Berry & Fairon-Demeret 1997

• Resembles the roots of Pseudosporochnus

• This taxon may represent the lower part of the trunk of Pseudosporochnus nodosus (Berry & Fairon-Demeret 1997)

Hierogramma †

• Unger 1856

• Givetian

• Small shoot axes

• Bilateral vascular system with two elongated xylem strands, one of which is T-shaped. 

• Distally, the vascular system becomes U-shaped. 

Lorophyton †

• Fairon-Demaret & Li 1993

• Eifelian - early Givetian

• Stout trunk with first order branches acutely inserted in a helical fashion

• Laterals axes from first-order are branched partly dichotomously. 

• The distal-most axes are either strap-like or recurved sporangiophores bearing paired sporangia

Pietzschia †

• Cross and Hoskins 1951

• Late Devonian (Famennian) of Morocco

• Similar anatomically to Pseudosporochnus

• The stems have a diameter of about 2.5 cm, and have a cylinder of radially arranged xylem plates

• P. schulleri (Gothan 1927)

  • From the Famennian of Morocco,

  • Primary tissue only; the trunk diameter is often more than 15 cm, the tribe has both central as well as peripheral xylem strands

• P. polyupsilon (Read and Campbell ?)

  • From the New Albany Shale of Kentucky, the number of xylem segments is 54

  • The main axis had determinate growth; the lateral axes were arranged in whorls

• P. timanica (Lepechina 1968)

• P. levis (Soria and Meyer-Berthaud 2004)

  • Lower Famennian (Upper Devonian) of Morocco has aerenchyma indicating that it lived in wetlands

Rhymokalon trichium †

• Scheckler 1975

• Upper Devonian (Frasnian) of New York 

• 3 cm thick stem axis

• The second and third order lateral axes are in a spiral arrangement. 

• Cross sections show a primary xylem strand of less than 1.8 cm in diameter

• Plates of xylem with parenchyma in-between

• The bark consists of elongated parenchyma cells.

Stenoxylon †

• Stenoxylon has plenty of secondary and reduced primary xylem. 

• Stenoxylon ludwigii has vessel segments anastomose to form a complex network of vascular systems. 

  • At the trunk are numerous small petioles in schraubiger arrangement. 

• Stenoxylon irvingense from the New Albany Shale has on one side of Xylemarms a stronger form secondary xylem than on the other. 

• The vascular bundles are more circular. In the parenchymatous ground tissue, there are irregular strips of thick-walled fibers.

Xenocladia †

• Arnold 1940

• Middle (Givetian) to Late Devonian (Frasnian)

• Liana growth form was proposed.

• Stems of Xenocladia medullosina have a diameter of about 10 cm and possess secondary xylem.