Erdtmanithecales

Reconstruction of microsporangiate organs of Eucommiitheca hirsuta, from Friis & Pedersen (1996).
Belongs within: Spermatophyta.

The Erdtmanithecales are a group of Cretaceous plants known from reproductive structures and seeds associated with Eucommiidites pollen; vegetative structures have not yet been identified for the group.

Characters (from Friis & Pedersen 1996): Male reproductive organs of closely spaced microsporangiate units; microsporangiate units stalked and peltate, bearing numerous sporangia in a radial arrangement around stalk; dehiscence of sporangia by longitudinal slits. Pollen grains of the Eucommiidites type dispersed singly; single grains elliptical in equatorial outline, bisymmetrical with two planes of symmetry through the polar areas and with a distal main colpus; main colpus typically expanded at the ends and flanked by two colpi or a single ring colpus in a proximal to almost equatorial position; pollen wall ultrastructure with granular infratectal structure and thick laminated endexine. Seeds small, orthotropous; megaspore membrane well developed; micropylar tube long and narrow, formed from inner envelope (inner integument).

<==Erdtmanithecales
    |--Erdtmanispermum balticum FC07
    |--Erdtmanitheca texensis FC07
    |--Eucommiitheca hirsuta FC07
    |--Bayeritheca hughesii FC07
    |--Eucommiidites FC07
    |    |--E. minor Groot & Penny 1960 I02
    |    `--E. troedsonii Erdtmann 1948 I02
    `--Spermatites FC07
         |--S. pattensis FC07
         `--S. patuxensis FC07

*Type species of generic name indicated

REFERENCES

Friis, E. M., & K. R. Pedersen. 1996. Eucommiitheca hirsuta, a new pollen organ with Eucommiidites pollen from the Early Cretaceous of Portugal. Grana 35 (2): 104-112.

[FC07] Friis, E. M., P. R. Crane, K. R. Pedersen, S. Bengtson, P. C. J. Donoghue, G. W. Grimm & M. Stampanoni. 2007. Phase-contrast X-ray microtomography links Cretaceous seed with Gnetales and Bennettitales. Nature 450: 549-552.

[I02] Ibrahim, M. I. A. 2002. Late Albian-Middle Cenomanian palynofacies and palynostratigraphy, Abu Gharadig-5 well, Western Desert, Egypt. Cretaceous Research 23: 775-788.