Periosteum

“ The perianth-leaves are generally almost free, with valvate, æstivation, often leathery. Small scales alternating with the perianth are often found at the base of the ovary. The stamens generally have extremely short filaments, and are situated opposite, sometimes quite on the tip of the perianth-leaves, in a spoon-like groove. The gynœceum is 1-locular, has 1–several ovules, and is often raised on a stalk-like internode. The fruit is a follicle or nut. The seeds, most frequently winged, have no endosperm.—Protea, Manglesia, Hakea, Banksia, Grevillea, etc. [451] 50 genera; about 1,000 species. ”

“ Inside the 6–12 perianth-leaves are situated in the ♂-flower 10–20 stamens with thick connective, and in the ♀-flower a gynœceum formed by one carpel, with one orthotropous and pendulous ovule, which has only one integument. Fruit a nut, which, in some species, bears on each side a pointed horn, and at the apex a similar one, formed by the persistent style.—The embryo has an unusually well developed plumule with several whorls of leaves. ”

“ On the left peristome edge is a large undulating membrane. It begins near the anterior end of the body and increases in height posteriorly following the peristome edge around on the right side. This posterior bend of the membrane causes the appearance of a full sail, so often seen. It can be entirely withdrawn and folded together in the peristome. On the right edge of the peristome are large, powerful cilia. The contractile vacuole is central and dorsal; the macronucleus is in the anterior half of the body, with one attached micronucleus. Food consists of bacteria. ”

“ In addition to the changes which fertilisation produces in the ovule itself, it also gives the impetus to a series of changes in the entire shoot which bears the ovule. The perianth, stamens, and style, generally wither, because the part they play is at an end; the wall of the ovary grows and becomes the wall of the fruit (pericarp) . The entire gynœcium of a flower, transformed as a consequence of fertilisation, is termed a fruit. It consists of two parts, the pericarp and the seeds, and according to the nature of the pericarp, the fruit is termed a capsule, nut, berry, or drupe. ”

“ Besides these, there are frequently two still smaller scales within the paleæ. There are generally three or six stamens, the anthers of which are two-celled, and forked at the extremity. There are two styles, either quite distinct, or combined at the base, and the stigmas are feathery. The pericarp is membranaceous, and adheres to the seed, forming a kind of caryopsides. The seeds contain a great deal of albumen, which, when ground into flour, becomes nourishing food. The stems, or culms, are hollow and articulated; the leaves, which are alternate, springing from each joint. ”

“ Male. Tawny, long, shining, pubescent, testaceous beneath; head pale luteous, with a broad black stripe, which is dilated on each side; a black U-shaped mark about the face, which is black; a large black spot on each side of the peristoma; palpi partly black; antennæ blackish at the tips, and with a black dot on each at the base; 3rd joint linear, rounded at the tip, more than twice the length of the 2nd; arista plumose; pectus with a minute blackish mark on each side in front; abdomen blackish, except towards the base, elongate-fusiform, much longer and narrower than the thorax ”

“ The perianth is composed very often of 4 (2 + 2) free, or in the ♀-flowers generally united, green leaves; the 4 (2 + 2) stamens are opposite the perianth-leaves, the filaments are bent inwards in the bud and throw themselves elastically towards the outside. The gynœceum has one style and one stigma (capitate or brush-like, Fig. 341) ; the ovary is unilocular, with one orthotropous, erect ovule (all other orders of this family have inverted or curved ovules) . Fruit, a nut or drupe. Endosperm present (in Urtica very little) , oily. Embryo straight. ”

“ The leaves are oblong, and spotted with purple. The inflorescence is a spike, the flowers crowded upon it, but separated by the long three-nerved green bracts. The structure of these flowers will be found to differ widely from all we have considered in these pages. The perianth is placed above the (consequently inferior) ovary, which is twisted. This twist, it will be well to bear in mind, brings the flower “upside down.” The three sepals and the three petals are equally coloured, and it is therefore convenient to speak of them as the perianth. ”

“ The tissue of the walls (trama) consists often (Lycoperdaceæ) of two kinds of hyphæ, some thin and rich in protoplasm, divided by transverse septa and bearing the basidia; others thicker and thick-walled which do not dissolve like the former on the ripening of the spores, but continue to grow and form a woolly, elastic mass, the capillitium, which may be regarded as highly developed paraphyses. The peridium may be either single or double, and presents many variations in its structure and dehiscence. The mycelium is generally a number of string-like strands, living in soils rich in humus. ”

“ The seeds are surrounded by the perianth which finally becomes red and fleshy. There are 30 species.—Gnetum has opposite, lanceolate, pinnately-veined, leathery leaves. They are mostly climbers (Lianas) from Tropical Asia and America. The ♂-flowers have a tubular perianth, (formed from two median leaves) which surrounds a centrally-placed filament, bearing 2 anthers. In the ♀-flower there is a similar perianth, surrounding an ovule provided with 2 integuments. The perianth becomes fleshy and envelops the hard seed. 20 species. ”

“ Nearly all trees or shrubs, seldom herbs, generally with latex. The leaves are scattered, and not infrequently lobed. The flowers are unisexual (monœcious or diœcious) and arranged in catkin- or capitulum-like, compound inflorescences. Perianth-leaves 2–6, generally 4, with an equal number of stamens opposite to them, as in the Nettles. The [354] ovary is 1–seldom 2-locular, and has 2 stigmas (it is thus formed from 2 carpels) seldom only one style with one stigma. One ovule in each loculus, more or less curved, and pendulous; micropyle directed upwards. Fruit usually a drupe. ”

“ The separation of layers in the apical meristem of the root is usually very much more obvious than in that of the stem. The outermost is the calyptrogen, which gives rise to the root-cap, and in Dicotyledons to the piliferous layer as well. The periblem, one cell thick at the apex, produces the cortex, to which the piliferous layer belongs in Monocotyledons; and the plerome, which is nearly always sharply separated from the periblem, gives rise to the vascular cylinder. ”

“ The plant is small, never growing to more than an inch and a fourth in diameter. The peridium is depressed globose, with a fibrous mycelium. The outer peridium is rather thick and when the plant is nearing maturity it breaks up readily unless handled very carefully; at maturity it scales off, except a small portion about the base. The outer peridium is white and comparatively smooth, the inner is thin, tough, smooth, lead-colored, dehiscent at the apex by a round or oblong mouth. Mass of spores and capillitium not solid or hard ”

“ With a tuft of hairs or hair-like branches. Perfect. Flowers with both stamens and pistils. Perfoliate. Leaves so clasping the stem as to appear as if pierced by it. Perianth. The modified floral leaves (sepals or petals) , regarded collectively. Pericarp. The wall of the fruit, or seed-vessel. Perigynium. The utricle enclosing the ovary or achene in the genus Carex. Perigynous. Borne on the perianth, around the ovary. Peripheral. Pertaining to the periphery. Persistent. Organs remaining attached to those bearing them after the growing period. Petal. One of the leaves of the corolla. Petaloid. ”

“ The divisions of this perianth, six in number, may, in truth, [153] be considered as petals; they are detached down to the base, and full in proportion as the pistil is developed. The latter is composed of three stigmata, attached, without the intermediary of a stylus (sessile stigmata) , to a free ovary (that is, an ovary not joined to the perianth) , which, as it develops, forms a capsule with three angular projections marking so many lobes; each of these lobes includes a great number of compressed seeds. ”

“ The perianth consists of five or six oblong greenish lobes, within which is found a tuft, consisting of a large number of stamens, each of which has a very short filament and an oblong two-lobed anther bursting longitudinally, and surmounted by an oblong lobe, which is the projecting end of the connective. There is usually no trace of ovary in the male flowers, though by exception one may occasionally be formed. ”

“ Style elongated, usually arched and protruding above the middle from the slit of the perianth-tube before the end is set free by the opening of the limb, finally erect and longer than the perianth, usually attenuate below the end, which is more or less thickened or dilated elliptical or linear, with a stigmatic slit descending from the apex to the middle or nearly to the base of the lower side. Fruit a small oblong or rarely ovoid obtuse indehiscent nut (or drupe?) with a single erect seed.—Shrubs sometimes almost growing into small trees, sometimes low and prostrate, often silky-villous. ”

“ The specimens are a little larger, depressed and angular. The peridium is paler, smoother, though sometimes almost black, thin, ruptured irregularly. But the form and color of the peridium in the sporocarps of the older species vary much in response to external conditions; on a substratum affording scant nutrition the forms of fructification are minute; and in all cases, if maturity be hastened, the peridium responds in darker colors. Under more favorable conditions the wall is smoother and brighter. ”

“ The whole structure is developed as a smooth white ball beneath the soil. But, once the spores are ripe, the outermost peridium splits open at the top, its lobes spring backward and outward, giving room for the second covering to burst in similar fashion. The lobes of the second, however, by recurving, hoist the entire inner structure out of the ground and up into the air, where the inner peridium, enthroned thus upon springing arches, groined by no human hand, opens at tip a purse-like mouth, and suffers the spores slowly to escape, to sail on unknown journeys with the passing breeze. ”

“ The flowers are supported by a bract, but have no bracteoles. In some genera the perianth is distinctly represented by six bristles corresponding to six leaves (Figs. 284 A, 286 A) ; in others it is represented by an indefinite number of hairs (Fig. 284 B) , and very frequently it is altogether wanting. The inner whorl of stamens is absent, and the flower has therefore 3 stamens (rarely more or less than 3) , the anthers are attached by their bases to the filament (innate) and are not bifid (Figs. 286) . Gynœceum simple, formed of 3 or 2 carpels ”

“ Stamens distinct; the oblong or linear anthers sheltered under the overarching petal-like stigmas (or rather branches of the style, bearing the true stigma in the form of a thin lip or plate under the apex) ; most of the style connate with the tube of the perianth. Capsule 3–6-angled, coriaceous. Seeds depressed-flattened, usually in 2 rows in each cell.—Perennials, with sword-shaped or grassy leaves, and large showy flowers; ours with creeping and more or less tuberous rootstocks. (Ἶρις, the rainbow, anciently applied to this genus on account of its bright and varied colors.) ”

“ Only a few solitary instances occur of individual species that are parasitic on living plants.
Fig. 42.—Sphæria aquila.
In the Sphæriacei, the substance of the stroma (when present) and of the perithecia is variable, being between fleshy and waxy in Nectriei, and tough, horny, sometimes brittle, in Hypoxylon. A perithecium, or cell excavated in the stroma which fulfils the functions of a perithecium, is always present. The hymenium lines the inner walls of the perithecium, and forms a gelatinous nucleus, consisting of asci and paraphyses. ”

“ Perigynium mostly light green or whitish, usually thin and membranous, often somewhat inflated or loosely investing the achene, commonly smooth and shining (hairy in n. 46, sometimes in n. 47) , slender or oblong, attenuate to a distinct or long minutely toothed straight beak (or beakless or nearly so in [+] 1 and n. 55) ; pistillate spikes several or many, mostly loosely flowered and on filiform nodding or widely spreading peduncles; bracts leaf-like; terminal spike staminate or androgynous; stigmas 3. Mostly rather tall and slender upland species. ”

“ In the instances of naked seeds now given, the bursting of the pericarpium precedes the distinct formation of the embryo, while the proper coats of the seed remain entire till after its separation from the parent plant, and germination has commenced.
It may not be uninteresting to contrast this economy with that of the Mangroves and other plants of tropical countries, which grow on the shores, and within the influence of the tide. In many of these the embryo, long before the seed loses its original attachment, acquires a very considerable size ”

“ In others there is a distinct central cylinder which occupies the axis of the stem, and consists of long and narrow cells; in the more complex forms the structure of the axial tissues suggests the central cylinder or stele of higher plants. The genus Polytrichum, so abundant on English moors, illustrates this higher type of stem differentiation. In a transverse section of the stem the peripheral tissue is seen to be composed of thick-walled cells, passing internally into large parenchymatous tissue. ”