Schinzia, which forms galllike swellings on the roots of rushes; Gymnosporangium, causing excrescences on juniper stems; numerous leaf Fungi such as Puccinia, Aecidium, Sep/one, &c., causing yellow, brown or black spots on leaves; or Ustilago in the anthers of certain flowers.
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.
Within the perianth, and springing from its sides, or apparently from the top of the ovary, are six stamens whose anthers contain pulverulent pollen-grains.
Some or all of the anthers become twisted so that insects in probing for honey will touch the anthers with one side of their head and the capitate stigma with the other.
Owing, however, to the close proximity of stigma and anthers, very slight irregularity in the movements of the visiting insect will cause self-pollination, which may also occur by the dropping of pollen from the anthers of the larger stamens on to the stigma.
The anthers shed their pollen into this groove, either of themselves or when the pistil is shaken by the insertion of the bee's proboscis.
The anthers are so situated that the pollen on escaping comes into contact with the stigma; in such flowers self-fertilization is compulsory and very effectual, as seeds in profusion are produced.
The flowers are borne in a terminal raceme, the anthers open introrsely and the fruit is a capsule, very rarely, as in Dianella, a berry.
Bulbous plants with a terminal racemose inflorescence; the anthers open introrsely and the capsule is loculicidal.
The plants generally have an erect stem with a crown of leaves which are often leathery; the anthers open introrsely and the fruit is a berry or capsule.
Evergreen shrub with flattened leaf-like cladodes, native in the southerly portion of England and Wales; the small flowers are unisexual and borne on the face of the cladode; the male contains three stamens, the filaments of which are united to form a short stout column on which are seated the diverging cells of the anthers; in the female the ovary is enveloped by a fleshy staminal tube on which are borne three barren anthers.
Terminating the short annual shoot which bears a whorl of four or more leaves below the flower; in this and in some species of the nearly allied genus Trillium (chiefly temperate North America) the flowers have a fetid smell, which together with the dark purple of the ovary and stigmas and frequently also of the stamens and petals, attracts carrion-loving flies, which alight on the stigma and then climb the anthers and become dusted with pollen; the pollen is then carried to the stigmas of another flower.
The slender filaments of the stamens vary widely, often in the same flower; the anthers are linear to ovate in shape, attached at the back to the filament, and open lengthwise.
The six anthers open by pores or short slits.
He states that the germ is never to be seen in the seed till the apices (anthers) shed their dust; and that if the stamina be cut out before the apices open, the seed will either not ripen, or be barren if it ripens.
Thus the anthers and stigmas in any given flower are often mature at different times; this condition, which is known as dichogamy and was first pointed out by Sprengel, may be so well marked that the stigma.
Has ceased to be receptive before the anthers open, or the anthers have withered before the stigma becomes receptive, when crosspollination only is possible, or the stages of maturity in the two organs are not so distinct, when self-pollination becomes possible later on.
The flower is termed proterandrous or proterogynous according as anthers or stigmas mature first.
Spontaneous self-pollination is rendered impossible in some homogamous flowers in consequence of the relative position of the anthers and stigma - this condition has been termed herkogamy.
G, Level of stigma; S, level of anthers; P, N, pollen grains and stigmatic papillae of long-styled form; p, n, ditto of short-styled form.
Flowers which are closed at the time of maturity of anthers and stigmas are termed cleistogamous.
In the simplest case the anthers are close to the stigmas, covering these with pollen when they open; this occurs in a number of small annual plants, also in Narcissus, Crocus, &c. In snowdrop and other pendulous flowers the anthers form a cone around the style and the pollen falls on to the underlying stigmas, or in erect flowers the pollen may fall on to the stigmas which lie directly beneath the opening anthers (e.g.
Numerous Saxifragaceae, Cruciferae and others), or the style, which first projects beyond the anthers, shortens later on so that the anthers come into contact with the stigmas (e.g.
The former, which is a somewhat less favourable method than the latter, is effected by air-currents, insect agency, the actual contact between stigmas and anthers in neighbouring flowers, where, as in the family Compositae, flowers are closely crowded, or by the fall of the pollen from a (From Darwin's by permission.) FIG.
4) the male flowers become detached and float on the surface of the water; the anthers are thus brought in contact with the stigmas of the female flowers.
A male flower has floated alongside a female and one of its anthers, which have opened to set free the pollen, is in contact with a stigma.
- Catkin of Male ing pendulous anthers and pro Flowers of Hazel.
In small flowers which are crowded at the same level or in flat flowers in which the stigmas and anthers project but little, slugs or snails creeping over their surface may transfer to the stigma the pollen which clings to the slimy foot.
Pratense, each whorl of stamens ripens in turn, becoming erect and shedding their pollen; as the anthers wither the filaments bend outwards, and when all the anthers have diverged the stigmas become mature and ready for pollination.
Self-pollination is rendered possible, since the divisions of the stigma begin to separate before the outer stamens have shed all their pollen; the nearness of the stigmas to the dehiscing anthers favours self-pollination.
Dematophora necatrix on roots, Calyptospora Goeppertiana on stems, Ustilago Scabiosae in anthers, Claviceps purpurea in ovaries, &c. Associated with these relations are the specializations which parasites show in regard to the age of the host.
The length of the style is determined by the relation which should subsist between the position of the stigma and that of the anthers, so as to allow the proper application of the pollen.
In Asclepiadaceae the stigmas are united to the face of the anthers, and along with them form a solid mass.
Changes are produced in the whorl of stamens by cohesion of the filaments to a greater or less extent, while the anthers remain free; thus, all the filaments of the androecium may unite, forming a tube round the pistil, or a central bundle when the pistil is abortive, the stamens becoming monadelphous, as occurs in plants of the Mallow tribe; or they may be arranged in two bundles, the stamens being diadelphous, as in Polygala, Fumaria and Pea; in this case the bundles may be equal or unequal.
The stamens may cohere by their anthers, and become syngenesious, as in composite flowers, and in lobelia, jasione, &c.
The opening or dehiscence of the anthers to discharge their contents takes place either by clefts, by valves, or by pores.
The anthers dehisce at different periods during the process of flowering; sometimes in the bud, but more commonly when the pistil is fully developed and the flower is expanded.
The anthers are called introrse when they dehisce by the surface next to the centre of the flower; they are extrorse when they dehisce by the outer surface; when they dehisce by the sides, as in Iris and some grasses, they are laterally dehiscent.
Sometimes, from their versatile nature, anthers originally introrse become extrorse, as in the Passionflower and Oxalis.
The usual colour of anthers is yellow, but they present a great variety in this respect.
They are red in the peach, dark purple in the poppy and tulip, orange in Eschscholtzia, &c. The colour and appearance of the anthers often change after they have discharged their functions.
Stamens occasionally become sterile by the degeneration or non-development of the anthers, when they are known as staminodia, or rudimentary stamens.