Families (page 1/2)
Trees are divided in two orders: entomophilous and anemophilous, depending on whether they are pollinated by insects and birds or by wind. Orders are declined in families according to the flower (pistils, stamens, arrangement). The members of these families are the genera which include the species of trees: it is here that are the main types of trees, for example the sessile oak. Species are finally differentiated in varieties, existing on a restrained territory, in cultivars, coming from selections made in culture or accidental mutations, and in hybrids, resulting from crossing between two species. We differentiate hybrids F1, generally unstable, and species of hybrid origin, which are stable species, capable of faithfully reproducing, by apomixis or doubling of the chromosomal number. Natural hybridization is one of the modality favouring the appearance of new species. Many known species are of hybrid origin, but are no longuer "hybrids" properly speaking.
Some tree varieties are distinguished by their shape (weeping or, on the contrary, fastigiate or pyramidal) or the colour of their foliage ("Aureum" or gilt, "Glauca" or aquamarine, "Purpurea" or purple). It is these particular species that often interest the botanists and the individuals.
Trees entomophilous (pollinated by fowls)
They are angiosperms ("seeds protected by an ovary") and hardwoods (they lose their leaves in winter), with a few exceptions (some magnolias and laurels have persistent leaves).
Their flowers are showy, attractive and often odorous or nectariferous, to attract insects, honeybees or hummingbirds, or even bats.
Always according to modes of reproduction, the following families are differentiated:
|Opposite leaves, without stipules. Flowers either hermaphrodite (male and female organs in the same flower), or unisexual. Flowers in clusters or in corymbs. |
- Peruvian Pepper tree
- Mango tree
|Some fruits are bitter-sweet |
|Flowers and fruits in stalked umbels. The family regroup climbing plants (ivy), trees and shrubs, most often from tropical origin. |
|Flowers, hermaphrodite, have a calyx bell-like, cut down or in 5 teeth, resembling the digital (in the shape of finger); the corolla is formed of 5 lobes, among which 3 are located above 2 others forming 2 lips so. Stamens, generally to the number of 5, alternate with the lobes of the corolla but, in general, one of them is sterile. Flowers are grouped in panicles. The fruit is most often a capsule, but is sometimes fleshy.
- Glossy abelia
- Viburnum opulus
|Flowers in panicles. The honeysuckle and the hydrangea are of the same family. |
|Flowers bisexuals include many stamens and ovaries superiors. |
- Persian Ironwood
|Trees dioecious. Flowers are tiny. Opposite leaves. |
- Chestnut tree
|Flowers are raised in thyrses (pyramidal shape regrouping around thirty flowers). |
- Avocado, Camphor laurel,
Flowers, yellow or green, symmetrical radiating, are grouped in inflorescences; the elements of the calyx and of the corolla, disposed on two ranks, are alike. The fruit is a berry or a false drupe.
Tough, entire leaves, devoid of stipule, containing oleaginous substances, as well as the bark.
- Bladder senna
- Locust tree
- Japanese Pagodatree
- Wisteria, with the wisteria
|They are characterised by their fruits which are pods. The pod is a dry fruit coming from the single one carpel and having two dehiscence cracks. Flowers are grouped in pendulous clusters. They are hermaphrodite (male and female organs in the same flower).
Their flowers have papilionaceous corollas (resembling butterfly wings), symmetrical in comparison with vertical plan we say "zygomorphic" for the symmetry in comparison with a plan). The first flowers mature before the appearance of the last flowers. Other feature: roots pick up the nitrogen of air and "enrich" the soil.
A metabolic feature of Fabaceae is the presence of a hemoprotein oxygen fixing, the leghemoglobin (or LegHb), very close to some haemoglobin.
- Judas tree
- Caesalpinia, with Pernambouc or Pau-Brasil
- Carob tree
- Kentucky Coffee Tree
- Locust tree
|Caesalpinioideae has a pseudo-papillonaceae flower.
- Silk Tree
|Flowers have numerous stamens and leaves are multipinnate. The trees of this subfamily fit to arid climates: small, pinnate leaves or bipinnates, or replacement by flattened petioles which can be differentiated of the true leaves by the veins which develop at the same time instead of being ramified.|
- Tulip tree
|Tulip flowers. |
|Flowers grouped on peduncles. compound leaves. |
|Small yellow flowers, in May, concealed by white bracts, bigger than leaves (20 cm). |
- False Holly
- Olive tree
- chionanthus, lilac, forsythia,
|Species sometimes monoecious, sometimes dioecious, and flowers sometimes unisexual, sometimes hermaphrodite. Two stamens, ovary in two lodges, compound of two fused carpels.
|Shrubs, fragile wood; rounded leaves, 12 pairs of regular veins. dried bark
- Snowy Mespilus
- Quince tree
- Pear tree
- Apple tree
|Flowers are round; 5 petals are divided into corolla, supported by a calyx of 5 sepals. One-three dozens of stamens (males). The fruit contains 1 or 2 pips, which are seeds, lodged in 2 - 5 carpels. The calyx is the shriveled remains of the sepals, style and stamens, under the fruit (for example under the apple or the pear). The skin is fleshy (you peel an apple). These trees tolerate transplants, which enables to improve cultivars.
- subfamily Amygdalaceae :
- genus Prunus
- Apricot tree
- Almond tree
- Portuguese Cherry Laurel
- Wild cherry tree
- Cherry Plum
|Contrary to the previous ones, these fruits have a stone and a fine skin (the cherry is not peeled!). These are drupes. There is not "calyx" on their base.
- Lemon tree
- Korean Evodia
- Orange tree
- Amur Corktree
|family Rue (Ruta), Mediterranean aromatic grass. |
By crumpling leaves, a sweet-scented essence is sniffed.
- Lichee, Longan,
- Varnish Tree, Xanthoceras
- Royal Paulownia
|Flowers in panicles, every flower resembling the digital (in the shape of finger), like the Catalpa. The Royal Paulownia is sometimes included into the family of the Catalpa (Bignoniaceae).
- Brachychiton, Cocoa, Cola, Sterculia
|Flowers, unisexual or hermaphrodite, are formed of a calyx developed by 3 - 5 sepals united at the base, of a corolla of 5 small petals, or apetalous, of stamens grouped in column. The ovary is located above the establishment of other flower organs with a gynaeceum formed by 5 carpels verticillate. Fruits often form mericarps. |
- Tree of Heaven
|Badly odorous, flowers in panicles attract insects nevertheless. Species dioecious. |
|Abundant white blossoming. |
|Its flowers, though small, emit a sweet fragrance in summer.