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Pellia: Identification and Classification

Systematic Position

  • Division: Bryophyta
  • Class: Hepaticopsida
  • Order:Jungermanniales
  • Sub-order: Metzgerineae
  • Family Pelliaceae
  • Genus Pellia

Pellia, a genus with only four species, is known to exist only in India. They are P.calycina, P.epiphylla, P.endivaefolia and P.neesiana. There is a claim for two more species to be added to this Genus. (P. columbiana and P. borealis)

Pellia endiviifolia

Pellia endiviifolia (Photo : Hermann Schachner)

Habit and Habitat

Pellia grows mainly in moist, shady places, especially by ditches and streams. They also grow on moist soil or rocks or in soil between rocks if it is shady. Sterile plant parts may be seen growing under frequently running shallow water while fertile plants tend to grow in exposed conditions.

External features

  • Thallus: prostrate, flat, dorsiventral, thin, with distinct broad mid rib
  • Branching: Dichotomous
  • Rhizoids: Unicellular, unbranched and smooth walled
  • Scales: Absent
  • Leaves arrangement: absent

Common Bryophyte Terminology

  • Thallus: A plant body that is not differentiated into stems and leaves, and lacks true roots and a vascular system. The plant body may be round with extended leaves or may be flat and ribbon-like.
  • Rhizoids: Hair-like structures on the thallus similar to roots
  • Dichotomous branching: Branching into two arms, or forking into two
  • Antheridium: Male sex organ -club shaped which contains androcytes. Each androcyte changes to a small, motile, biflagellate antherozoid.
  • Archegonium: Female sex organ – flask-shaped. Archegonium contains an egg or oosphere.
  • Zygote: The result of fertilization by the penetration of the large, non-motile oosphere by the small, motile antherozoid.

Internal features

  • Thallus shows no differentiation and is composed of parenchymatous cells which serve the purpose of food storage.
  • Apical growth is by single apical cell with four cutting faces.

Reproduction

  • Plants are monoecious or dioecious.
  • Antheridia – male sex organ: Immersed inside the cavity on the dorsal surface of the thallus
  • Stalk : short and few celled
  • Jacket: One layered
  • Archegonia- female sex organ: Present on the anterior end of the dorsal surface of the thallus
  • Neck: Consists of 5 vertical rows of cells
  • Neck canal cells: 6-8
  • Cover cells – 4
  • Venter: two layered

Sporophyte

  • Foot: Conical, forming collar-like outgrowth and covering a part of the seta
  • Seta: Present
  • Shape of Capsule: Globose
  • Capsule Wall: Two or more cell layers, persistent
  • Amphithecium forms: Jacket of the capsule
  • Endothecium forms: Archesporium
  • Archesporium forms: Spores, elaters and elatorspores
  • Dehiscence mechanism: Wall splits into four valves. Elaters help in the dispersal of spores.


Amanda Dcosta
 

Amanda writes about botany and plants from the deserts of Oman where summer temperatures climb to 130 Fahrenheit. Amanda has a BSc in Botany and is a co-author of Encyclopedia of Cultivated Plants: From Acacia to Zinnia. Read more articles by Amanda.

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