Riccia L.

Systematic position

Division: Bryophyta
Class: Hepaticopsida
Order: Marchantiales
Family: Ricciaceae
Genus: Riccia

Distribution and habitat

The name Riccia was given in honor of P. F. Ricci, a Florentine politician. It is the most widely distributed genus among the liverworts. It has about 152 species across the world and 36 species are reported from in India (Devi et al., 2019).
But for the Riccia fluitans, all the species are terrestrial and prefer to grow in moist and shady habitats. Riccia grow on the soil, on the wall, in the crevices of rocks and bricks. Riccia fluitans is aquatic and grows floating on or submerged in stagnant water.
There are eight bryogeographical regions in India and most common species from these regions are R. attenuata Pandé, R. crispatula Mitt., R. cruciata Kashyap, R. discolor Lehm. and Lindenb., R. fluitans L., R. gangetica Ahmad, R. glauca L., R. sorocarpa Bisch. R. curtisii (Austin) Austin and R. pathankotensis Kashyap.

Various species of Riccia in their habitats showing rosette habitat

Gametophytic phase

Main plant body of Riccia is gametophytic and thalloid (undifferentiated). The plant body is fleshy, prostrate and dichotomously branched. In prolonged favorable conditions, repetitive dichotomous division results into the rosette (round) appearance (above photograph). The thallus very small in size measuring 5-7 mm long and 1-2 mm broad. The thallus of aquatic species, R. fluitans is however long measuring up to 50 mm long and up to 2 mm broad.

A rosette thallus of Riccia cavernosa

References

Devi, N.P., Yumkham, S.D. and Singh, P.K., 2019. Two new records of Riccia L.(Ricciaceae) for the Eastern Himalaya Bryogeographical Region of India. Journal of Asia-Pacific Biodiversity, 12(4), pp.626-630. (https://doi.org/10.1016/j.japb.2019.08.005).

First published on 13-04-2021
Last updated on 01-05-2021

See also

Riccia general characteristics