Marchantiopsida Doweld
Creators: name: Ruklani, Sumudu
name: Rubasinghe, Sumudu C. K.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Marchantiophyta
Marchantiopsida

description: Key to the families of sterile complex thalloid liverworts of Sri Lanka
1. Thallus well differentiated into layers with air chambers ..................................................................................................................2
- Thallus weakly differentiated into layers without distinct air chambers.................................................................. Dumortieraceae
2. Thallus with compound air pores in the epidermis, gemmae present cupules cup-shaped..................................... Marchantiaceae
- Thallus with simple air pores in the epidermis, gemmae absent or present, cupules not cup-shaped ...............................................3
3. Gemmae present in crescent-shaped cupulues ............................................................................................................ Lunulariaceae
- Gemmae absent ..................................................................................................................................................................................4
4. Thallus very thin, 2-layered, translucent ..................................................................................................................... Cyathodiaceae
- Thallus thick, several layered, not translucent ...................................................................................................................................5
5. Air chambers with chlorophyllose filaments......................................................................................................................................6
- Air chambers without chlorophyllose filaments.................................................................................................................................7
6. Thallus green with purplish pigmentation ................................................................................................................... Targioniaceae
- Thallus green, without purplish pigmentation .......................................................................................................... Exormotheceae
7. Ventral scales in 2 or several rows, appendages absent ..................................................................................................... Ricciaceae
- Ventral scales in 2 rows, with 1–4 appendages ............................................................................................................... Aytoniaceae
Key to families of fertile complex thalloid liverworts of Sri Lanka
1. Perigonial chambers on stalked receptacles .......................................................................................................................................2
- Perigonial chambers aggregated in cushions or embedded in groups on dorsal surface of thallus or on short branches ..................3
2. Perigonial receptacles bearing compound air pores, stalk with 2 to 4 rhizoid furrows; involucre bivalved or cup-shaped; pseudoperianths present............................................................................................................................................ Marchantiaceae
- Perigonial receptacles bearing few open-air chambers, stalk with 2 rhizoid furrows; involucres tubular, bristly, opening by a slit; pseudoperianths absent............................................................................................................................................. Dumortieraceae
3. Sporophyte on stalked receptacles .....................................................................................................................................................4
- Sporophytes lacking receptacles.........................................................................................................................................................5
4. Perigonial chambers aggregated in terminal cushions on thallus; seta massive, elongating prior to spore dispersal.......................... ..................................................................................................................................................................................... Lunulariaceae
- Perigonial chambers embedded in dorsal groove of thallus or in irregular rows on thallus; seta remaining short............................6
5. Sporophytes embedded singly in the thallus; involucres absent; seta absent; elaters absent; capsules cleistocarpous ..... Ricciaceae
- Sporophytes ventral at the thallus apex; involucres bivalved; seta remaining short; elaters few per capsule; capsule dehiscence by a lid and irregular valves ....................................................................................................................................................................7
6. Receptacles bearing compound air pores; involucres bivalved, cup-shaped or flap-like; capsule dehiscence by a lid ....................... ......................................................................................................................................................................................... Aytoniaceae
- Receptacles bearing simple air pores, stalk with 1 rhizoid furrow; involucres tubular; capsule dehiscence by irregular valves or irregular lid and valves .......................................................................................................................................... Exormothecaceae
7. Thallus thicker (more than 2 layers), not translucent; antheridia borne on special branches; sporophyte in a dark, swollen, mussellike bivalved involucre below the thallus apex foot and seta of sporophyte well developed ...................................... Targioniaceae
- Thallus very thin, 2-layered, translucent; antheridia scattered in clusters along the edge of the thallus; sporophyte in an apical notch on the ventral thallus surface; foot and seta of sporophyte represented by a single filament ..................................... Cyathodiaceae
Key to the genera of Complex Thalloid liverworts of Sri Lanka
1. Thallus with cupules.......................................................................................................................................................................... 2
- Thallus without cupules......................................................................................................................................................................3
2. Gemma-receptacles cup-shaped; dorsal epidermis with compound pores....................................................................... Marchantia
- Gemma-receptacles crescent-shaped; dorsal epidermis with simple pores......................................................................... Lunularia
3. Photosynthetic tissue with narrow, vertical, channel-like air chambers or air chambers vestigial ....................................................4
- Photosynthetic tissue with air-chambers in one or more layers .........................................................................................................5
4. Air chambers absent, thallus weakly differentiated into layers........................................................................................ Dumortiera
- Air chambers in more than one layer or channel-like, thallus well differentiated into layers................................................... Riccia
5. Thallus very thin, 2-layered, translucent ......................................................................................................................... Cyathodium
- Thallus thick, several layered.............................................................................................................................................................6
6. Ventral scales hyaline, without appendages .................................................................................................................. Exormotheca
- Ventral scales purplish, with appendages ...........................................................................................................................................7
7. Ventral scales with 1 appendage; sporophytes ventral at the thallus apex ........................................................................... Targionia
- Ventral scales with 1 to 4 appendages; sporophytes on stalked receptacles.......................................................................................8
8. Ventral scales with ovate to lanceolate appendages; appendages purplish pink to hyaline, not constricted at base............................ ...................................................................................................................................................................................... Plagiochasma
- Ventral scales with 2 or 3 filiform appendages ..................................................................................................................... Reboulia
description: Published as part of Ruklani, Sumudu & Rubasinghe, Sumudu C. K., 2022, Thalloid Liverworts (Marchantiopsida) of Sri Lanka, pp. 1-82 in Phytotaxa 551 (1) on pages 14-15, DOI: 10.11646/phytotaxa.551.1.1, http://zenodo.org/record/6655548