Cormophyte are the most evolved vegetation, whose body (called “Cormo”) is made up of cells that form three organs: root, trunk and leaves. From the transformation of leaves originates flowers and fruits. Here are represented the main morphological characteristics of these organs and the related nomenclature.
Usually it is an hypogeum organ, with positive geotropism; its functions are to anchor the plant in the ground, absorb water and oligoelements, and collect reserve substances.
This type of root originates from the trunk, or, sometimes, from the leaves. This phenomenon is used in some vegetative reproduction techniques (scion, layer (“margotta”), offshoot propagation) for the propagation of cultivated plants.
THE ROOT IN THE SOIL
Development. The whole root system development, especially in species which are adapted to arid climates, goes beyond that of the remainder.
Depth. It is not rare that in herbaceous plants the root reaches levels with a depth of meters (ex. 1 meter in alfalfa).
Length. Adding up all roots lengths of a plant we obtain astonishing values: – 500 m for wheat plant, 4 km for a pumpkin, -500 km in a 20 years-old birch.
Taproot. From collar originates the main root which tend to enlarge: lateral rootlets remain little and short. This type is typical of dicotyledon.
Fibrous root. From the collar the main root divides into branching roots which also branch out forming a complex and highly developed apparatus. This is typical of monocotyledon.
VEGETATIVE MOLTIPLICATION (or cloning)
The newborn plant originates through a detachment of vegetative components which can take root when put in contact with soil. This is widely used in cultivated plants because every example (clone) keeps characteristics and genetic makeup of the starting plant.
Scion. A vegetative part (trunk, branch, limb or leaf) in suitable temperature and humidity conditions is planted to take root.
Offshoot. In a moat dug near the offshoot propagation plant there is the extension of a branch, then there is the covering with soil. For a period the branch remains stuck to the mother plant, from which detach when become independent tanks to roots.
Layer (“margotta”). The branch which will multiply is wrapped into a “muff “ of soil contained in a specific receptacle (“portamargotta”). The coppice layer is widely used an it is obtained by covering with soil the entire stump.
It is usually an epigean organ with negative geotropism; its functions are the support of the plant and the nutrients transport. It also brings buds from which branches and leaves originate.
Trunk anatomy. Dicotyledon trunk transverse section (epidermis, cortical parenchyma, conducting bundles, collenchyma, parenchyma, marrow).
Monocotyledon trunk transverse section : corn (Zea mays) (epidermis, conducting bundles, parenchyma).
Suffrutex. Branched at the basis, with woody branches at the bottom and herbaceous branches at the top.
Frutex or bush. Similar to the above mentioned, but completely woody.
Tree. Branches at a certain height in limbs with a more and more smaller diameter (herbaceous trunks and woody trunks)
Erect trunk, climbing trunk, crawling trunk, unstable trunk.
Stolon: horizontal crawling, growing at the soil surface
Spine: shorten and sharp branch
Root stock: horizontal underground, with squamiform leaves
Tuber: underground, strongly enlarged, brings bud in the so called “eyes”
Cladode: flattened with the aspect of a leaf, gives flowers and fruits
Tendril: transformed into a grasping organ
Bulb: shortened, around which lots of fleshy leaves are rounded up.
This organ is inserted in the trunk in the correspondence of the knots, exchanges gas (H 2O, CO2, O2) with the atmosphere and through photosynthesis starts the production of organic compounds (needle-shaped, bifacial and isofacial leaves).
- Leaf blade or lamina: photosynthesis
- Stalk: transport and support
- Stipule: protection
Petiolated leaf and sessile leaf
- Seasonal, deciduous, short-lived: this type lives only one vegetative season, falls in the same period and renews every year.
- Persistent: lives many years, doesn’t fall simultaneously and renews step by step
- Orbicular, Circular
- Acicular, Needle-shaped
- Cordate, Heart-shaped
Venation: veins disposition on the lamina
- Palmate (palm veins)
- Pinnate (quill-like arranged veins)
- Parallel (axially arranged)
Phyllotaxis: leaves disposition along the trunk in a manner that permits the maximum exposition of the upper face to sunbeams.
- Alternate, one leaf per node
- Opposite, two leaves per node
- Whorled (Verticillate), three or more leaves per node
Compound leaves: if margin incisions reach the central vein the leaf is called compound and the lamina is divided in parts called leaflets.
- Palmately-compound leaf
- Pinnately-compound leaf
- Odd pinnate, i.e. Pinnately-compound with a terminal leaflet
Leaves adaptation: leaves can undergo transformation in their shape and/or function
- Slender tendrils used to grasp
- Spines hardened and stinging in succulent plants in order to reduce transpiration
- Bracts, with many functions, involucres, reserve, attraction of pollinators
This organ derives from the ovary transformation after ovule fecundation. It consists of a seed-wessel that contains and protects seeds.
Fleshy fruits: when ripeness is complete epicarp is juicy; it is possible to notice, from the outside, the exocarp, the mesocarp and the endocarp.
Drupe: membranous and coloured exocarp (peel), fleshy and sugary mesocarp (pulp) and a lignified endocarp (stone) containing the seed.
Hesperidium: membranous exocarp, chlorate, rich in essential oils, whitish and spongy mesocarp, endocarp divided in juicy slices with seeds.
Pepo: hard and leather-like exocarp, mesocarp and endocarp with a lot of seeds.
Berry: membranous exocarp, fleshy mesocarp and endocarp surrounding many seeds.
Accessory fruits: derive from the enlargement of other parts of the flower besides the ovary
Syconium: the real fruits are internal achenes (“small seeds”) contained in the enlarged receptacle.
Pome: the real fruit is the “core” that is enveloped into a fleshy and sugary receptacle.
Dehiscent dried fruits: when ripeness is complete seed-wessel (pericarp), highly dried, opens in order to allow seed dispersion
- Capsule: is made up of many carpels, releases seed by lengthwise opening (valve dehiscence) or through pores (poricidial dehiscence)
- Legume or pod: it is made up of a carpel with seeds attached to the main vein.
- Silique: made up of two carpels with seeds arranged over a central septum (“Replo”)
- Non-dehiscent dried fruits: the pericarp, dried and leather-like, wraps only one seed from which it doesn’t detach when ripeness is completed
- Caryopsis: the fruit is developed with the seed and is not detectable. It is typical of Grass family
- Nucule or nut: leather-like pericarp with only one seed
- Achene: small dimension and woody, sometimes it is equipped with plumy (thistledown) and alary (ash-keys) expansions in order to promote wind dissemination or hooks good to stick to mammals fur
Spermatophyta reproductive system, originating from a trunk branch, the peduncle, over whose swollen extremity, the receptacle or thalamus, insert many diverse whorls called “antofilli”, modified floral leaves which become flower petals.
- First whorl: a calyx made up of sepals (a)
- Second whorl: a corolla made up of petals (b)
- Third whorl: androecium made up of stamens, each one made up of filaments and anther (c)
- Fourth whorl: gynoecium with pistil made up of ovary (e), style (f) and stigma (g)
- Unisexual flowers (with only stamens or pistils)