Rhyniophytes †

Morphology

Sporophyte (spore-bearing phase)

Stems / Axes

• Similar to the early polysporangiophytes, such as Aglaophyton, these plants show increasing diversification of axis types. These early plants are constructed with indeterminate and determinate structures like modern plants.

• Determinate aerial stems: above ground, upright axes (3 mm wide) which terminate in sporangia for dispersal (20 cm tall)

  • Branching is isotomous, anisotomous, and even pseudomonopodial

• Indeterminate rhizomes: ground-running, or below ground portions, that creep similar to vegetative propagate the population

  • Vesicular arbuscular mycorrhizae found in the cortex of Rhynia rhizomes

• Adventitious branching: latent "buds" or branches, which could elongate to make new axes, similar to modern plants.

• Vascular tissue present, but not the same as eutracheophytes (see S-type tracheids below)

  • Haplostele with centrarch maturation and S-type tracheids (i.e., annular or helical thickenings made of spongy material)

Eocooksonia sphaerica †

• Xue et al., 2015

• Originally Cooksonella (Senkevitsch, 1978; Doweld, 2000)

• Upper Silurian (Pridoli) of Xinjiang, Northwest China and Central Kazakhstan

• Pseudomonopodial branching pattern, which forms an apparent main axis with lateral dichotomously branching systems. 

• Specimens demonstrate terminal sporangia with a central body and a border with four to eight elongate-triangular emergences

Filiformorama simplexa †

• Yi et al., 2006

• Late Silurian (Pridoli) of north Xinjiang, China

• Plant has naked axes and a dichotomous branching

• Sporangia terminates one of the branches of a dichotomy, and the other daughter branch continues to grow and dichotomizes further.

• Sporangia are circular, but some are reniform or tongue-shaped, with an asymmetric base.

• There are no anatomical features that place this taxon in Rhyniales or tracheophytes in general

Right: Filiformorama compression (Yi et al., 2006, Figure 1, C & D)

Rhynia gwynne-vaughanii †

• Kidston & Lang, 1917

• From the Rhynie chert in Aberdeenshire, Scotland

• Rhizomatous plant with upright isotomous and anisotomous axes

  • • Upright axes were up to 3 mm wide and roughly 20 cm tall

    • Axes had a centrarch haplostele

• Sporangia were spindle-shaped (fusiform) and terminal

• Possible deciduous lateral branches were used to disperse laterally over the substrate and stands of the plant and may therefore have been clonal populations

Salopella †

S. australis

• Tims & Chambers, 1984

• Late Silurian (Ludlovian) - Early Devonian (Pragian) of Victoria, Australia

• Axes with at least 2 dichotomies (0.9-2.4 mm wide)

• Plants at least 145 mm tall

• Sporangia 6.5-14.0 mm long and 1.3-2.0 mm wide

S. cf. marcensis

• Edwards et al., 1994

Yarravia † 

• Lang & Cookson, 1935

• Pragian of Victoria, Australia

• Axes 2 to 2.5 mm in diameter, and up to 7.5 cm in length. 

• No examples of branching or anatomy known 

• The sporangia born radially in groups of 5-6 at the ends of axes.

• Base of sporangia are fused together, but tips may be free; the entire structure can be described as a synangium

Y. oblonga

• • Lang & Cookson, 1935; McSweeny et al., 2021

  • In Y. oblonga, the synangium (the group of fused sporangia) was longer than wide, being about 7 mm long by 1.25 mm wide. The tips of the sporangia were free and appear to consist of tissue not containing spores. 

Y. subsphaerica

• • Lang & Cookson, 1935

  • The synangium of Y. subsphaerica was significantly larger and as long as wide, being about 1 cm in length and width

  • The tips of the sporangia were less prominent

Y. minor 

• • Danzé-Corsin, 1956

Y. gorelovii

• • Ananiev, 1960