1. Coleochaete: Morphology & Reproduction
Ganesh Kumar
Asst. Professor-
Botany
MBC Govt. Girls
College Barmer
2. Occurance:
● The genus Coleochaete (Gr. Keleon, sheath; chaetos, hair) is
represented by about 10 species, out of which 3 species are found in
India.
● They grow in fresh water either as epiphytes on different angiosperms
(Trapa, Hydrilla, Ipomea, Sagittaria, Typha, etc.) and algae (Oedogonium,
Vaucheria) or as endophytes (C. nitellarum) within the cells of Chara
and Nitella (Chlorophyceae).
3. Morphology
● Plant body is thalloid, multicellular and of two types:
● (a) Cushioned forms:
● Cushioned forms, such as Coleochaete pulvinata show clear heterotrichous
habit with a prostrate and an erect system.
● Erect system is very much branched and combine to form cushion.
● (b) Discoid forms:Discoid forms, such as Coleochaete scutata and C.
nitellarum, are represented mainly by prostrate system. Filaments in this
system combine and form discin which the cells remain arranged radially.
4. Morphology continued…..
● Thallus is surrounded by a sheath of mucilage in both the types.
● All the species are characterized by the presence of some fine hairs
called setae.
● A basal sheath is present at the base of these hairs.
● These hairs are not permanent structures.
● Each cell is slightly elongated, uninucleated with parietal chloroplast.
● In general, cells possess single pyrenoid only.
5. Asexual Reproduction
During spring or early summer, asexual reproduction
takes place by the formation of zoospores. Any cell of
the plant body may function as zoosporangium. Each
zoosporangium produces single zoospore.
Zoospores are ovoid, unicellular, uninucleate and
biflagellate structure with a large parietal chloroplast.
Eye-spot is absent.
The zoospores are liberated from the zoosporangium
through a pore on the sporangial wall. It loses flagella
within a short time and secretes a wall on the periphery.
6. Sexual Reproduction
● Sexual Reproduction is of oogamous type.
● Antheridia are formed in marginal cells
and are present intermingled.
● In each antheridium, single, colorless and
biflagellate antherzoid develops.
● Oogonia also develop in marginal cells.
● Each oogonium is flask like structure
which contains a single egg.
● After fertilization, some branches develop
around the oospore which surrounds it
completely known as spermocarp.
