Which one of the following is the real difference between Marchantia and Funaria?
In Marchantia spores develop into adult gametophyte but in Funaria they develop into a juvenile filamentous gametophyte.
In Funaria, the haploid spore is the first cell of the gametophytic generation. It is small, spherical, measuring 12-20 pm in diameter. Under favourable environmental conditions, the spore germinates. The germ tube elongates, becomes septate and produces a filamentous protonema. The protonema branches freely and forms two types of branches viz., chloronemal branches and rhizoidal branches. The chloronemal branches possess conspicuous chloroplasts in their cells and become green in colour. The rhizoidal branches develop below the substratum, brown in colour. The rhizoidal filaments are primarily meant for anchoring the protonema in the substratum.The chloronemal branches develop many minute buds and each bud grows into an erect leafy gametophore. They become independent shortly after the death of the protonema. A dense growth of the plants is observed because of this property. An young gametophyte comprises of leafy stem, rhizoids arid protonema.
In Marchantia, spores remain viable for about a year. Under favourable conditions, they absorb moisture from the substratum and increase in size. At this stage, chloroplasts reappear. Subsequently, the spore divides transversely to form two unequal cells - the smaller cell forms the first rhizoid, while the larger cell undergoes irregular divisions to form a filamentous structure which ultimately forms the normal Marchantia thallus.