Calamitaceae †

Ecology & Form

• Evidence shows they inhabited wetland environments 

Stems

• Distinct nodes and internodes (bamboo-like appearance)

  • Arthropitys is form genus for permineralized stems; Astromyelon is form genus of permineralized rhizomes, distinguished from Arthropitys by the absence of carinal canals

  • Internodes are hollow; nodes are solid and woody

  • Stems exhibited a vascular cambium with wood production, but not secondary phloem 

  • Periderm or bark has been observed in the fossil Arthropitys (Cichan and Taylor 1983)

• Pseudomonopodial growth

  • Upright stem and side branches formed from unequal division of an apical cell

• Whorled branches 

Leaves

• Whorled leaves at nodes; up to 25 leaves per whorl

• Laminate and photosynthetic in forms (Annularia), and needle-like forms (Asterophyllites)

Roots

• True roots are present

Reproduction

• Sporangia aggregated into a cone (Calamostachys)

• Sporangia are on recurved stalks, called sporangiophores, and inserted in a whorled fashion

• Eusporangiate: Sporangia are larger with many spores

• Spores exhibit arm-like elaters, which aid in wind dispersal

  • Elaters react to humidity; opening in dry air and wrapping around spore in humid air