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Porella: Identification and Classification

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Porella is the only genus in the family Porellaceae and is found everywhere, except in the Arctic and Antarctic regions. They grow to about 15 cm in height, are green or blackish green in color, and grow on rocks or stony habitats, though at times even in soil.

Classification

  • Division: Bryophyta
  • Class: Hepaticopsida
  • Order: Jungermanniales
  • Sub order: Jungermannineae
  • Family: Porellaceae
  • Genus: Porella

Habit and habitat

Porella grows in temperate and tropical regions, mainly in the hills. A total of 184 species have been identified. They grow in moist, shady places, on bark of trees, rocks, etc.

Plant body: Gametophyte

  • Thallus: leafy axis, dorsiventral and prostrate
  • Branching: Monopodial, terminal
  • Rhizoids: Unicellular, unbranched and smooth walled
  • Scales: Absent
  • Leaves arrangement: In 3 rows, 2 rows of dorsal leaves, 1 row of ventral leaves(under leaves). All cells alike and unistratose

Internal features

  • Axis: Epidermis is not well differentiated. Cortex consists of small thick walled cells. The cells of the central portion are large and thin walled
  • Apical growth: By a single tetrahedral apical cell with 3 cutting faces

Reproduction

  • Plants are dioecious
  • Antheridia – male sex organ: Axillary and present on special antheridial branch
  • Stalk : long and 2 cells broad
  • Jacket: 2-3 cells thick in the basal part and single layer in the upper part
  • Archegonia- female sex organ: Present on the tip of special archegonial branch
  • Neck: Consists of 5 vertical rows of cells
  • Neck canal cells: 6-8
  • Cover cells – 4
  • Venter: two layered

Sporophyte

  • Foot: Slightly bulbous and distinct from seta
  • Seta: Present
  • Shape of Capsule: Globose
  • Capsule Wall: Two layered, persistent
  • Amphithecium forms: Jacket of the capsule
  • Endothecium forms: Archesporium
  • Archesporium forms: Spores and elaters
  • Dehiscence mechanism: Wall splits into four valves. Elaters help in the dispersal of spores.

Use an identification guide to help identify bryophyte specimen. The most common laboratory equipment that you will require are microscope, slide, blade, plant specimen, and stain, if necessary.

Porella: Identification and Classification
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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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