Sporangium
A sporangium is a
plant or
fungal structure producing and containing
spores. Sporangia occur on
angiosperms,
gymnosperms,
ferns, fern allies,
mosses,
algae, and
fungi.
Microsporangia are the structures on the stamens of
flowers called
anthers, and the pollen-producing structures on the microsporophylls of male
conifer cones.
Megasporangia are the comparable "female" structures on these plants, associated with the flower
carpel and the megasporangial cone.
On
ferns, the mature plant is a sporophyte that develops sporangia, tiny, stalked sacs which contain
meiospores, on all or just certain leaves .
Encyclopedia
A
sporangium is a
plant or
fungal structure producing and containing
spores. Sporangia occur on
angiosperms,
gymnosperms,
ferns, fern allies,
mosses,
algae, and
fungi.
Microsporangia are the structures on the stamens of
flowers called
anthers, and the pollen-producing structures on the
microsporophylls of male
conifer cones.
Megasporangia are the comparable "female" structures on these plants, associated with the flower
carpel and the megasporangial cone.
On
ferns, the mature plant is a sporophyte that develops sporangia, tiny, stalked sacs which contain
meiospores, on all or just certain leaves .
In mosses, the little case that rises above the vegetative growth on a thin
stalk is a sporangium often called a
capsule that, as in ferns, produces meiospores. This sporophytic growth arises out of the gametophytic
archegonium after the ovum is fertilized. The sporophyte initially has some
chlorophyll, but later turns brown and becomes dependent upon the gametophyte for nutrition, which is absorbed through the
foot , embedded in the archegonial tissues.
Categorized based on developmental sequence,
eusporangia and
leptosporangia are differentiated in the vascular plants. In a leptosporangium, found only in ferns, development involves a single initial cell that becomes the stalk, wall, and spores within the sporangium. There are around 64 spores in a leptosporangium. In a eusporangium, characteristic of all other vascular plants and some primitive ferns, the initials are in a layer . A eusporangium is larger , and its wall is multi-layered. Although the wall may be stretched and damaged, resulting in only one cell-layer remaining.
A cluster of sporangia that have become fused in development is called a
synangium. This structure is most prominent in
Psilotum is a genus of fern [i]-like vascular plant [i]s, the sole genus in the family Psilotacea ...
.
See also
