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54 | LAXMI [Rotony Practical], , , , , , , , MARCHANTIA, , Classification :, , Division : Bryophyta, Class : Hepaticopsida, Order : Marchantiales, Family : Marchantiaceae, Genus : Marchantia, , Vegetative structure :, , ee pe, , wt, , Pe, , The dominant phase of the marchantia is a gametophytic thallus., , It is prostrate, dorsiventral and dichotomously branched., , The dorsal surface of the thallus has prominent mid rib in each branch., , There are polygonal areas also on this surface. These areas represent the air chambers in the thallus, that open by a small dot like airpore., , A number of small cup like structures called gemma cups are present along the mid ribs. These cups, have a number of small gemmae which show vegetative propagation. ‘, , ‘The ventral surface of the thallus bears rhizoides and scales., , ‘These rhizoides are of two types (i) smooth walled and (ii) tuberculated with peg like in growths, , Scales are present in rows on sides of mid ribs. These are of two different shapes (i) single (ii) ligulate, , , , , ae (A), ‘8 : Marchantia polymorphia ; Thallus : (A) Dorsal, , structure of thallus :, , (B), view, (B) Ventral view, , per green Photosynthetic zone, , rectangular ph, There are barrel shaped air pores in the es hat cells,, , Each airpore consists of 4-8 superimposed ti, , ; d tiers of cell,, Air chambers are present below the e; idermi: a arated fr, of green photosynthetic cells, Pia Tay 99 ne a m one another by 2-4 celled ee, , and the lower storage regio”.

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58 | LAXMI [Botony Practical), , Sporophyte or the sporogonium /, The sporogonium is the sporophyte phase and develops from zygote after fertilization., , The sporogonium hangs downwards. It has the following structure :, 1. Foot : It is the broad basal part. It is made up of parenchymatous cells. It absorbs nutrition from the, gametophyte for the developing sporogonium., 2 Seta : It connects the foot with capsule. It is made up of cells arranged in vertical rows., , 3. Capsule : It is oval in shape and yellow coloured at maturity. It has a wall made up of cells with, , thickenings. Inside the capsule wall, there is a mass of meiospores (n) and elaters., , The elaters are long slender cells with pointed ends. They are dead and hygroscopic when mature, A, Spore has an outer thick layer exine and inner thin intine. Elaters help in dispersal of spores., , Assimilatory filaments, , , , Tuberculate ee, , , , : bigc Macchanhe sp : A vertical Fig. : M ;, longitudinal section through archegoniophore TES. Spon Polymorpha :, a9