JUNGERMANNIALES
1. Plant body is thalloid ( pellia ) or foliose ( porella , frullania ) .
2. Thallus is not differentiated in to photosynthetic and storage region ( unlike to marchantiales ) .
3. Air chambers and air pores are absent ( unlike to marchantiales ) .
4. Elatophores may be present in basal ( pellia ) or apical ( riccardia ) region of capsule .
5. Vegetative reproduction takes place usually by gemmae .
6. Jungermanniales may be anacrogynae = metzgerineae ( apical cell of thallus is not fully utilized in archegonia ) or acrogynae = jungermannineae ( apical cell of thallus is fully utilized in the last archegonia ) .
7. Archesporium develops from endothecium .
8. Archegonium neck is made up of 5 vertical rows of neck canal cells ( characteristic feature ) .
Pellia
Plant body is flat , prostate , dorsiventral and dichotomously branched . Thallus is irregularly lobed with sinuous margins . Each lobe is supplied with mid rib . Numerous smooth walled unicellular rhizoids are present along mid rib . They are not up to apical notch . On dorsal side , antheridia are along midrib and archegonia are close to apex of thallus . Antherozoids in pellia are elongated , spirally coiled and biflagellate . Capsule of pellia has spores, elaters ( with spiral thickening ) and basal elatophores ( characteristic feature ) . Elaters have two spiral thickenings .
Porella ( Madotheca )
Porella is flat , dorsiventral and foliose . It bears 3 rows of leaves - 2 dorsal ( lateral ) rows and one ventral row of amphigastria . Dorsal leaves are large but amphigastria are small leaves . Dorsal leaves have large antical lobe and small postical lobe . They also have elaters with spiral thickening .
Frullania
They are similar to porella . Elaters and spore mother cells are arranged in alternate vertical rows in capsule . Capsule splits in 4 halves .