Families (page 2/2)
Trees anemophilous (pollinated by the wind)
They are pollinated by the wind. Flowers are small and discreet, but very many, grouped in catkins, so as to augment chances of success of dispersion of the pollen and of reception by females. On hardwoods, catkins arrive at maturity at the end of winter, before leaves, so as to favour dispersion by the wind.
They are either Gymnospermes or angiosperms.
Anemophilous Gymnospermes: their seeds are not protected by an ovary. Most are resinous (they produce the resin), except the Ginkgo, Sequoia, Hemlocks.
order of Conifers:
- Norway Spruce
- False cypress
- Hinoki Falsecypress
- Dawn Redwood
- Sequoia, Taïwania
|Their fruits are grouped in cones. Scales protect the winged seeds which are liberated in the wind when they are ripe. |
|the pine makes easier the access of the pollen by secreting a drop micropylar at the entrance of the ovule. |
|Flowers appear at the end of branches in March-April. Fruits are cones, smaller to Arborvitaes and False cypresses (1 cm) than to the Cypress (2 cm). Leaves in scales. |
|the male catkins appear ats the axil of leaves (flat or triangular needles) at the end of the winter or in spring. Fruits are cones, elliptical or spherical. Leaves are arranged spirally round stems (except in the Dawn Redwood). |
order of Ginkgoales,
- f. from Ginkgoaceae
|Species dioecious (male feet # female feet). Primitive reproduction: the bare ovule grows previously, to attain a shape of bowl (that it would be possible to take for a fruit). Spermatozoons are transported by a pollen liquid towards the egg what reminds the archaic pollination of the fern. The sprout develops immediately after the germination, without passing by the stadium of the seed. Its leaf is also primitive: without vein. |
|order of Taxales:|
- Cephalotaxeae :
- English Yew (Taxus), Torreya
Species dioecious. Fruits under leaves.
Anemophilous angiosperms ("in seeds protected by an ovary").
Species dioecious (male feet # female feet):
|They carry male catkins. |
|They carry male catkins: |
- Walnut: in May, at the top of the twig , before leaves.
- Wingnut: in April, with leaves.
- Fig tree
- Orange tree of Osages
|Flowers, unisexual, are grouped in inflorescences|
For the Paper Blackberry and the Orange tree of Osages, the female flowers are bowls of 1 cm in diameters (glomerules), ruffled of purple hair papiloses which are stigmata.
Fruits are either drupes, or false fruits, formed by the magnification of other parts of the flower, as container (the Fig tree).
|the male flowers (stamens) and the female flowers (ovary) are accompanied by a small leaf (bract), hirsute at the base, hence the aspect of catkins of flowers grouped. Seeds enveloped by hair taken by the wind. Lightweight, no endosperm (food reserves), short-lived. The catkins of the willow produce a nectar which attracts insects (# poplar). |
|the female flowers are on the high stems. |
- Plane tree
- Fagaceae :
- Spanish chestnut
|the male flowers disperse the pollen in May, before the maturity of the female flowers; the pollen settles on the pistil, by waiting until July.
The top of the stems where females roost, grows, becomes hard, and around the ovaries, forming a cup nudes: bug chestnut capsule enclosing the acorn or beechnut.|
- Ulmaceae :
- European Hackberry
|Flowers are hermaphrodite. They appear from February and are fertilised without insects (in hibernation) and without the wind : green fruits from April. Leaves alternate or in spiral (distichous). Stipules deciduous (appendices at the base of the leaf).