Naegeli at once recognised their essential agreement with the antheridia already known in the Bryophytes and compared the spermatozoids with the corresponding structures in animals.
But in Anthoceros, while he recognised the antheridia he was not clear as to the sunken archegonia, and regarded the capsules as arising by impregnation of unrecognisable spots on the young frond or thallus.
In it he redescribes the antheridia and spermatozoids--detecting their tufted cilia which Naegeli had overlooked.
Mycelium poorly developed or absent; oogonia and antheridia (without antherozoids) known in some cases; zoospores common: Chytridiaceae.
In the rotting tissues branches of the older mycelium similarly swell up and form antheridia and oogonia (fig.
Mycelium present; antheridia but no antherozoids; oogonia with one or more oospheres: Peronosporaceae, Saprolegniaceae.
Fungi with segmental thallus; sexual reproduction sometimes with typical antheridia and oogonia (ascogonia) but usually much reduced.
The ordinary mycelium is the gametophyte since it bears the ascogonia and antheridia when present; the ascogenous hyphae with their asci represent the sporophyte since they are derived from the fertilized ascogonium.
The Peronosporaceae reproduce themselves sexually by means of antheridia and oogonia as described in Pythium.
Monoblepharis has oogonia with single oospheres and antheridia developing a few amoeboid uniciliate antherozoids; these creep to the opening of the oogonium and then swim in.
The antheridia, which arise in the conceptacular cavity as special cells of branched filaments, are similarly discharged whole, the antherozoids only escaping when the antheridia are clear of the conceptacle.
Great numbers of antheridia are usually crowded together, when the part is distinguishable by the absence of the usual red colour.
The antheridia are spherical orange-coloured bodies of very complex structure.
The antheridia and oogonia are formed at the nodes of the appendages.
The antheridia (an) are scattered over the middle region of the thallus, and each is surrounded by a tubular upgrowth from the surface.
The antheridia are usually globular and long-stalked.
The brown tint of the hair-like paraphyses mixed with antheridia (fig.
The small thallus bears the antheridiaand archegonia, each of which is surrounded by a tubular involucre, on the upper surface of distinct individuals.
The stalked globular antheridia are exceptional in being formed endogenously, and are situated in groups in special intercellular spaces.
The individual antheridia are sunk in depressions from which the spermatozoids are in some cases forcibly ejected.
Their general similarity to the mature antheridia and archegonia of liverworts and the main difference in their development have been referred to.
The antheridia open by means of a cap cell or groups of cells with mucilaginous contents.
The superficial layer of cells bounding the cavity does not break down until the antheridiaare nearly mature.
The sexual organs, with the exception of the antheridia of Sphagnum, are borne at the apices of the main shoot or of branches.
The scattered position of the antheridia is also found in some of the higher forms, but usually they are grouped on special antheridiophores which in Marchantia are stalked, disk-shaped branch-systems (fig.
The sexual organs are borne on the upper surface, and both antheridia and archegonia occur on the same branch (fig.
Occasionally antheridia develop on the surface of shaded portions of the thallus.
The antheridiaare protected by leaves which are often modified in shape.
The slightly thickened membrane of the antheridia encloses protoplasm which is finely granular.
Immediately after the formation of the antheridia new productions show themselves, both around the oocyst and within it.
After the evacuation of the antheridia the gonospheres are found to be covered with cellulose; they then constitute so many oospores, with solid walls.
De Bary and Pringsheim believe that these organs constitute the antheridia of the species of Saprolegnia to which they belong.
The antheridia are borne singly at the bases of the leaves on the special branches already described (Fig.
Antheridia are often wanting, and even when they are present, it is very doubtful whether fertilization takes place.
The act of fertilization may be easily observed by laying fresh antheridia into a drop of water containing recently discharged egg cells.
By carefully dissecting with needles such a branch in a drop of water, some of the antheridia will usually be detached uninjured, and may be readily studied, the full-grown ones being just large enough to be seen with the naked eye.
Under favorable conditions, the firstantheridia are ripe in about five weeks; the archegonia, which are borne on separate plants, a few weeks later.
The sexual organs are often produced in these forms upon special branches (G), or the antheridia may be sunk in discs on the upper side of the stem (D, an.
If these are carefully separated, the antheridia can just be seen as minute whitish globules, barely visible to the naked eye.
In G, one of the antheridia has discharged the mass of spermatozoids (an.
N, O, antheridiathat have partially discharged their contents, × 300.
The spore-cases may be seen scattered over the surface of the frond as so many black dots, and the antheridia are elongated, cylindrical bodies attached to tufted filaments on all parts of the frond.
Defn: Having stamens and pistil in the same head, or, in mosses, having antheridia and archegonia on the same receptacle.
Defn: A minute jointed filament growing among the archegonia and antheridia of mosses, or with the spore cases, etc.
A minute jointed filament growing among the archegonia and antheridia of mosses, or with the spore cases, etc.
Having stamens and pistil in the same head, or, in mosses, having antheridia and archegonia on the same receptacle.
Antheridia large, pedicelled, solitary in the axils of 2-cleft spicate leaves.
Antheridia 3--20, in the axils of small saccate leaves, which are scarcely imbricate or crowded into terminal heads.
Antheridia immersed in the thallus, covered with dentate scales.
Cryptogamous plants with a distinct axis or stem, growing from the apex, and commonly not with later increase in diameter, usually furnished with distinct leaves; reproduction by antheridia and archegonia, sometimes also by gemmation.
Antheridia imbedded in an oval disk sessile near the apex of the thallus.
Plants with cellular tissue only; both antheridia and archegonia borne upon the plant itself.
Antheridia in the base of closely imbricated leaves.
Antheridia or archegonia, or both, formed upon the stem or branches of the plant itself, which is developed from the germinating spore usually with the intervention of a filiform or conferva-like prothallus.
In the centre of these leaves, which must be separated with mounted needles in a drop of water, the antheridia (fig.
The antheridia contain large numbers of exceedingly minute spermatozoa, furnished with two cilia, and very similar to those existing in the antheridia of the mosses; these, escaping through the pore of the conceptacle, fertilize the spores.
The antheridia may be best examined in Polytrichum piliferum or commune, the patches of stems with red rosette-like heads (figs.
The reproduction is effected by the agency of two kinds of organs, antheridia and capsules (sporangia), situated near each other (fig.
If the antheridia are quite ripe, they swell somewhat in the water, and from the free or unattached end a very delicate, colourless, cellular mass gradually escapes.
The antheridia produce spermatozoa, and the sporangia each a spore, the one fertilizing the other in the ordinary manner.
If theantheridia are not quite ripe, the mass must be liberated by dissection.
These are probably the representatives of the anthers of flowering plants and of the antheridia of the ferns.
Only by the complicated method of first a spore then the prothallus, from which archegonia and antheridia are produced, followed by the free swimming male cells fertilizing the female, can a fern reproduce itself.
The minute motile filaments of the antheridia fertilize the large spores after injection into the water: and then the latter promptly acquire a cell-wall and germinate.
In the case of a perfectly normal prothallus the male organs or antheridia are to be found amongst the root hairs, whilst the female organs or archegonia arise from a cushion, several cells deep, more towards the centre of the process.
However that may be, as soon as the underside of the prothallus has become thoroughly wetted the antheridia open, and certain little bodies called spermatozoids are allowed to escape.
The same moisture which caused the antheridia to open also brings about the opening of the archegonia.
From the underside arise more root hairs, and it is here also that the antheridia (male organs) and the archegonia (female organs) are produced.
The sexual generation is a small green thalloid structure called a prothallium, which bears antheridia and archegonia, each archegonium having a neck-canal and oosphere, which is fertilized just as in the moss.
The antheridia are stalked sacs, with a single wall of cells, and the spiral antherozoids arise by free-cell formation from the cells of the interior.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "antheridia" in a variety of sentences. We hope that you will now be able to make sentences using this word.
