The sporangium with its endogenous spores has been compared with an ascus, and on these grounds the group is placed among the Ascomycetes--a very doubtful association.
In these three genera the conidia are cast off with a jerk somewhat in the same way as the sporangium of Pilobolus.
As mentioned before, the connexion between these two groups is very doubtful, and the derivation of the ascus from an ordinary sporangium of the Zygomycetes cannot be accepted.
According to his view, the ascus is in effect the sporangium with several spores, the conidium the sporangiole with but one spore, and that not loose but fused with the sporangiole wall.
A slender support of any special organ, as that of a capsule in mosses, an air vesicle in alg\'91, or a sporangium in ferns.
Having the sporangium destitute of a ring; -- said of certain genera of ferns.
The line of dehiscence of the sporangium of a fern.
The capillitium of a very short sporangium of Stemonitis Webberi, Rex; the breadth, however, somewhat exaggerated.
Sporangium ovoid, more or less elongated; the calyculus small, plicate-sulcate.
Sporangium globose; the wall shining with colors of blue, purple, and bronze, deciduous.
Stipe short, sometimes very short or nearly obsolete, snow-white, expanding at the base into a small white hypothallus, tapering upward and entering the sporangiumas a short obtusely conical columella.
Stipe long, erect, dark purple to purplish black, tapering upward and entering the sporangium as a slight obtuse columella.
Sporangium regular and stipitate or sessile, rarely plasmodiocarp; the wall a thin membrane, usually granular or venulose on the inner surface, colored as the spores and capillitium, irregularly dehiscent.
Sporangium simple, subglobose and stipitate, the base commonly umbilicate, or sometimes sessile and plasmodiocarp; the wall a thin membrane with an outer layer of minute stellate crystals of lime.
Sporangium elongated ovoid, pale yellow, stipitate; the upper part of the wall disappearing at maturity, leaving a small cup-shaped persistent base.
Sporangium globose, the columella not reaching its center.
Stipe long, slender, translucent, pale red to dark red in color, tapering upward, entering the sporangium and prolonged nearly to the apex as a slender columella.
Defn: Having the sporangium destitute of a ring; -- said of certain genera of ferns.
Defn: A sporangium or conceptacle containing only large spores; -- opposed to microsporangium.
A slender support of any special organ, as that of a capsule in mosses, an air vesicle in algæ, or a sporangium in ferns.
The male or pollen-bearing organs were produced straight on the foliage in much the same way as the sporangiumof a true Fern is developed.
Now and again in certain species it is seen that the megaspores develop to such an extent within the sporangium that fertilization takes place, and even an embryo or young plant may be formed.
As in the case of Lycopodium there is only one sporangium to each leaf, but they are of two kinds.
In the larger spores (megaspores) these represent the embryo sac, and the sporangium in which they are produced closely approximates to the part containing the embryo sac in the Flowering Plant.
The capsule of the sporangium is much flattened, and has not been inaptly compared to a watch-case.
For a more complete description of the sporangium of the Fern the reader is referred to a succeeding chapter.
To return to our Male Fern, the annulus is plainly seen to start from the stalk of the sporangium at one side of the capsule, and it can be traced right over the top to a situation about half-way down on the other side.
The chief business of the annulus is to bring about the opening of the sporangium in such a way that the spores are violently expelled.
In some families a prominent feature is the fact that the sporangium has little or no stalk, although this is the exception rather than the rule.
The sides of the capsule start to draw inwards, and ultimately the annulus suddenly straightens out and the sporangium is torn open, the actual rupture taking place just at the base of the ring.
When the contents of the sporangium are mature the wall of the capsule, and especially the cells forming the annulus, begin to lose water.
The number of spores produced in the sporangium of a Male Fern is usually some forty-eight to sixty-four, although in other species there might be less than the lower figure or more than the higher.
When the individual sporangium is examined it is found that there is often present an annulus, a special ring of cells which plays an important part in the rupturing of the case.
Each sporangium produces a considerable number of spores, so that every cone is responsible for an enormous number.
The manner in which the spores originate in the sporangium calls for comment.
The sporangium is quite a large affair, easily discerned with the naked eye.
In a few moments the sporangium is empty and the spores disappear from the field of the microscope.
Their number in a sporangium are from six to sixteen in P.
After the sporangium is ripe, cross partitions in irregular order and number often appear in the inner space, and on the upper surface branches of different number and size, each of which forms a sporangium at its point.
When opened by irregular dehiscence from above, the persisting cup-like base of the sporangium recalls Leocarpus fragilis; but then again the capillitium is different.
The spores of this species resemble closely those of the preceding, but the sporangium is at sight different in appearance and proportions and the capillitium not the same at all.
The lines of fruiting tend to follow the venation of the supporting leaf; where the sporangium is round, the columella is a distinct rounded or cake-like body; where the fruit is venulose, the columella is less distinct.
Associated with the spores in the sporangium occurs the capillitium.
One of the smallest species of the genus, by its proportionally long stipe and small round sporangium reminding one somewhat of P.
The ribs or costae of the spore-case radiate from the top of the stipe and unite again at the top of the sporangium in a feeble, irregular net.
The remarkable shape of thesporangium and the peculiar regularity of the surface net, the lateral columella, all combine here to warrant the erection of a distinct species.
After the archegonia are fertilized the outer parts of the ovule become hard and brown, and serve to protect the embryo plant, which reaches a considerable size before the sporangium falls off.
The central cell, whose contents are much denser than the outer ones, divides again by walls parallel to those first formed, so that the young sporangium now consists of a central cell, surrounded by two outer layers of cells.
C-E, successive stages in the development of the sporangium seen in optical section, × 150.
F, a secondsporangium forming below the empty one.
As soon as the sporangium is emptied, a new one is formed, either by the filament growing up through it (Fig.
In the upper cell several walls next arise, forming a short stalk, composed of three rows of cells, and an upper nearly spherical cell--the sporangium proper.
The wall of the ripe sporangium or pollen sac is composed of a single layer of cells in most places, and these cells are provided with thickened ridges which have to do with opening the pollen sac.
When fully grown, the sporangium is globular, and appears quite opaque, owing to the numerous granules in the protoplasm filling the space between the columella and its outer wall.
When ripe, the end of the sporangium opens, and the contained cells are discharged (Fig.
A, mother cell of the sporangium of the maiden-hair fern, × 300.
The outer walls of the sporangium now become hard, and the whole falls off as a seed.
When the ripe sporangium becomes dry, the ring of thickened cells (an.
When ripe, the wall of the sporangium dissolves, and the spores (Fig.
When the spores in the sporangium are mature and therefore ready for the next stage in their life history several things must happen.
Carolinianum, and (1) a magnified scale of the spike removed, with the sporangiumin its axil, discharging powdery spores.
Sporangia borne in a double row on narrow fertile segments, each sporangium seated on a separate veinlet, and provided with a special scale-like indusium.
The sporangium has an inner membranaceous peridium; the whole is round, brown, whitish.
Scale and sporangium from the lower part of the cone, containing macrospores.
The upper sporangium contains microspores, the lower macrospores; hence it has the character of Triplosporites.
Scale and sporangium from the upper part of cone 51 (3).
Sporangium with its valves separated, containing a quantity of black carbonaceous matter in its interior (Balfour).
Scale and sporangium from lower part of cone, containing macrospores 51 (6).
The sporangium is filled with a great number of very small spores, each composed of three roundish bodies or sporules.
Very numerous tetrads enclosed in a spore case orsporangium which develops on a leaflike segment called the sporophyll.
Two sporangia were attached to each bract, but their stalks were of different lengths, so that one sporangium lay near the axis and one lay outside it toward the tip of the bract.
S, large spore within the sporangium wall w; s, the three aborted spores of the tetrad to which S belongs.
In a fern sporangium germinating spores were fossilized so as to show the first divisions of the spore cell.
Each sporophyll was shaped like a small umbrella with four spokes, and stood at right angles to the axis, bearing a sporangium at each of the spokes.
The spore develops in a special mass of tissue known as the nucellus, n, which partly corresponds to the sporangium wall of the previous types.
Spores" of Seedlike Structure Out of a tetrad in each sporangium only one spore ripens, S in figure, the others, s, abort.
Spores Each a single cell like the preceding, but here only one tetrad in a sporangium ripens, so that each contains only four spores.
In each sporangium large numbers of these tetrads develop and all the ripe spores seem to have been of one size.
The plan of each is that round the axis of the cone simple scales are arranged, on each of which, on its upper side, is seated a large sporangium bearing numerous spores all of one kind (see fig.
The sorus was regarded as a sort of compound fruit, the sporangium as a carpel, the annulus as its midrib, and the spores as the seeds.
He dwelt on the similarity of the sporangium and indusium of Azolla to a gymnospermus ovule, and regarded the filaments of Anabena seen penetrating within the indusium as probably the fertilising bodies in this naked-seeded cryptogam.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "sporangium" in a variety of sentences. We hope that you will now be able to make sentences using this word.
