Monoecious, and bearing their male flowers in catkins, they are readily distinguished from the rest of the catkin-bearing trees by their peculiar fruit, an acorn or nut, enclosed at the base in a woody cup, formed by the consolidation of numerous involucral bracts developed beneath the fertile flower, simultaneously with a cup-like expansion of the thalamus, to which the bracteal scales are more or less adherent.
70); no nectocalyces or bracts; appendages all on the lower side of the pneumatophore arising from a compact coenosarc, and consisting of a central After C. Gegenbaur.
Bracts of Strelitzia, &c.), and in the root of the carrot.
Long, and have pale-yellow anthers, bearing tufts of hairs at the apex; the female attain a length in the fruiting stage of 2 to 4 in., with bracts i to 12 in.
The yew-like leaves spread laterally, and are of a deep green tint; the cones are furnished with tridentate bracts that project far beyond the scales.
The large cones stand erect on the branches, are cylindrical in shape, and have long bracts, the curved points of which project beyond the scales.
The flowers are arranged in racemes without bracts; during the life of the flower its stalk continues to grow so that the open flowers of an inflorescence stand on a level (that is, are corymbose).
The bracts are usually scale-like, but sometimes foliaceous, as for instance in Calystegia, where they are large and envelop the calyx.
The yellow stamen-bearing flowers are in sessile, nearly spherical catkins; the fertile ones vary in colour, from red or purple to greenish-white, in different varieties; the erect cones, which remain long on the branches, are above an inch in length and oblong-ovate in shape, with reddish-brown scales somewhat waved on the edges, the lower bracts usually rather longer than the scales.
Long, purplish or green in the immature state, and dark brown when ripe, the scales somewhat more numerous, the bracts all shorter than the scales.
The leaves are short, thicker and more rigid than in any of the other larches; the cones are much larger than those of the hackmatacks, egg-shaped or oval in outline; the scales are of a fine red in the immature state, the bracts green and extending far beyond the scales in a rigid leaf-like point.
Amethystinum, 2 ft., has the upper part of the stem, the bracts, and heads of flowers all of an amethystine blue.
Plants whose beauty resides in the bracts or floral leaves which surround the inconspicuous flowers.
Characias, 2 to 3 ft., with green bracts, are fine plants for rockwork or sheltered corners.
Across, and the variety bracteatum closely resembles it, but has leafy bracts just beneath the blossom.
Sclarea, 5 to 6 ft., is a very striking plant little more than a biennial, with branched panicles of bluish flowers issuing from rosy-coloured bracts; S.
Generally, however, the flower-bearing portion of the plant is sharply distinguished from the foliage leafbearing or vegetative portion, and forms a more or less elaborate branch-system in which the bracts are small and scale-like.
B, b', Upper and lower membranous spathe-like bracts; c, Tube of perianth; d, Ovary; e, Style; f, Stigmas.
The Poinsettia pulcherrima of gardens (Euphorbia pulcherrima of botanists), a native of Mexico and Central America, with its brilliant scarlet bracts, stands unrivalled amongst decorative plants.
Resembling leaf-buds, and have protruding crimson stigmas; the minute inner bracts, by their enlargement, form the palmately lobed and cut involucre or husk of the nut.
- Catkin of Hazel (Corylus Avellana), consisting of an axis covered with bracts in the form of scales, each of which covers a male flower, the stamens of which are seen projecting beyond the scale.
The latter are borne three together, invested by a cupule of four green bracts, which, as the fruit matures, grow to form the tough green prickly envelope surrounding the group of generally three nuts.
Several species are grown as hot-house plants for the bright colour of their flowers or flower-bracts, e.g.
The bracts on the flower-stalk are either small and scattered or large and leafy, and then placed near the flower, forming a sort of outer calyx or epicalyx.
The two bracts are, however, on different axes, one secondary to the other, and cannot therefore be parts of one whorl of organs.
Bracts of a more general character subtending branches C' of the inflorescence are singularly rare in Gramineae, in marked contrast with Cyperaceae, where they are so conspicuous.
The persistent bracts (glume and pale) afford an additional protection to the fruit; they protect the embryo, which is near the surface, from too rapid wetting and, when once soaked, from drying up again.
Less absolute characters, but generally trustworthy and more easily observed, are the feathery stigmas, the always distichous arrangement of the glumes, the usual absence of more general bracts in the inflorescence, the split leaf-sheaths, and the hollow, cylindrical, jointed culms - some .or all of which are wanting in all Cyperaceae.
The female heads are spinose with long pungent bracts, fall entire when ripe and are carried away by wind or sea, becoming finally anchored in the sand and falling to pieces.
After fertilization, some of the uppermost bracts below each flower become red and fleshy; the perianth develops into a woody shell, while the integument remains membranous.
The spike of an inflorescence bears whorls of flowers at each node in the axils of concrescent bracts accompanied by numerous sterile hairs (paraphyses); in a male inflorescence numerous flowers occur at each node, while in a female inflorescence the number of flowers at each node is much smaller.
Each cone consists of an axis, on which numerous broad and thin bracts are arranged in regular rows; in the axil of each bract occurs a single flower; a male flower is enclosed by two opposite pairs of leaves, forming a perianth surrounding a central sterile ovule encircled by a ring of stamens united below, but free distally as short filaments, each of which terminates in a trilocular anther.
- Fruit of the pine-apple (Ananas saliva), consisting of numerous flowers and bracts united together so as to form a collective or anthocarpous fruit.
The crown of the pine-apple, c, consists of a series of empty bracts prolonged beyond the fruit.
The cone of Sphenophyllum consisted of an axis bearing at the nodes whorls of bracts, united below into a sheath.
The overlapping bracts afforded protection to the sporangia, which were borne on sporangiophores springing from the upper surface of the coherent bracts near their origin from the axis; two sporangiophores usually arose from each bract, and sometimes adhered to its upper surface for some distance.
In Cheirostrobus a similar relation of sporangiophores to bracts existed, but here each bract was divided into three segments.
That these three sterile segments, with their sporangiophores, are together comparable to one of the bracts of Sphenophyllum, with its sporangiophores, is shown by the vascular supply in each case being derived from a single leaf-trace, So far as is at present known, the Sphenophyllales were homosporous.
The generally one-seeded nut-like fruit is associated with the persistent often hardened or greatly enlarged bracts forming the so-called cupule which gives the name to the group. The group is subdivided as follows, and these subdivisions are now generally regarded either as distinct natural orders or the first two as sub-orders of one natural order.
Female flowers arranged, two to three together on scale-like structures formed by the union of bracts, in catkins; ovary two-celled; fruit small, flattened, protected between the ripened scales of the catkin.
Female flowers in pairs, the bracts enlarging in the fruit to form a membranous cup (hazel), or a flat three-lobed structure (hornbeam).
Bracts forming a fleshy or hard cupule which envelops the one to several fruits.
Bracts sometimes do not differ from the ordinary leaves, as in Veronica hederifolia, Vinca, Anagallis and Ajuga.
When the flower is sessile the bracts are often applied closely to the calyx, and may thus be confounded with it, as in the order Malvaceae and species of Dianthus and winter aconite (Eranthis), where they have received the name of epicalyx or calyculus.
In many cases bracts act as protective organs, within or beneath which the young flowers are concealed in their earliest stage of growth.
When bracts become coloured, as in Amherstia nobilis, Euphorbia splendens, Erica elegans and Salvia splendens, they may be mistaken for parts of the corolla.
A series of empty coloured bracts terminates the inflorescence of Salvia Horminum.
The smaller bracts or bracteoles, which occur among the subdivisions of a branching inflorescence, often produce no flower-buds, and thus anomalies occur in the floral arrangements.
Bracts are occasionally persistent, remaining long attached to the base of the peduncles, but more usually they are deciduous, falling off early by an articulation.
Thus, the cones of firs and the stroboli of the hop are composed of a series of spirally arranged bracts covering fertile flowers; and the scales on the fruit of the pine-apple are of the same nature.
At the base of the general umbel in umbelliferous plants a whorl of bracts often exists, called a general involucre, and at the base of the smaller umbels or umbellules there is a similar leafy whorl called an involucel or partial involucre.
In Compositae the name involucre is applied to the bracts surrounding the head FIG.
- Head (capitulum)of Marigold (Calendula), showing a congeries of flowers, enclosed by rows of bracts, i, at the base, which are collectively called an involucre.
Such whorled or verticillate bracts generally remain separate (polyphyllous), but may be united by cohesion (gamophyllous), as in many species of Bupleurum and in Lavatera.
In Compositae besides the involucre there are frequently chaffy and setose bracts at the base of each flower, and in Dipsacaceae a membranous tube surrounds each flower.
Bracts also compose the husky covering of the hazel-nut.
When bracts become united, and overlie each other in several rows, it often happens that the outer ones do not produce flowers, that is, are empty or sterile.
In the artichoke the outer imbricated scales or bracts are in this condition, and it is from the membranous white scales or bracts (paleae) forming the choke attached to the edible receptacle that the flowers are produced.
The sterile bracts of the daisy occasionally produce capitula, and give rise to the hen-and-chickens daisy.
In place of developing flower-buds, bracts may, in certain circumstances, as in proliferous or viviparous plants, produce leaf-buds.
5, gl); and in Cyperaceae bracts enclose the organs of reproduction.
Bracts are frequently changed into complete leaves.
This change is called phyllody of bracts, and is seen in species of Plantago, especially in the variety of Plantago media, called the rose-plantain in gardens, where the bracts become leafy and form a rosette round the flowering axis.