Carrot leaves are simple or compound. In a number of plants (carrots, wheat, oats), the base of the leaf grows and covers the stem. Possible diseases and ways to combat them

What is the importance of leaves in plant life? To answer this question, get acquainted with the structure of the leaf and the life processes that occur in it.

Compare the juicy, fleshy, prickly-edged leaves of the agave with the wide, dense, leathery leaves of the ficus.

How different these leaves are from each other indoor plants! Remember the delicate, almost lacy leaves of carrots and large leaves cabbages curling into a head. Even the leaves of the most common trees and shrubs are so different that it is difficult to confuse the leaves of birch and linden, maple and oak.

There are leaves very large and very small. In the Moscow Botanical Garden, the tropical aquatic plant Victoria cruciana blooms annually in the summer. Its leaves are so large that a three-year-old child can sit on them, like on a raft, and the leaf floats freely on the water. And the weed plant woodlice has leaves smaller than a fingernail. Some plants have leaves that have turned into tiny green scales or spines, such as cacti, camel thorn and many other plants of dry places.

Externally leaves different plants They are very different from each other, but they have a lot in common.

The leaves of most plants are green in color and consist ofleaf blade and petiole, with which they are attached to the stem. Some plants do not have petioles. Petiolate leaves are called sedentary. Agave, flax, agave and many other plants have such leaves. Leaves with petioles - petiolate - are available in almost all of our trees: birch, oak, maple, linden, ash and many others. Sometimes, at the base of the leaf petiole, stipules.

According to the shape of the leaf blade, leaves can be round, oval, lanceolate, linear, etc.

The shape of the edge of their blade is also distinguished among leaves. For example, the edge of the plate may be jagged, like that of birch. The edge of the leaf blade can be entire, like that of lilac, and then the leaf is called entire.

There are leaves with serrated, notched, crenate, wavy, doubly-toothed and doubly serrated edges. See the shape of the edge of the sheet in the figure.

Have you ever found unusual leaves consisting of only veins among last year’s foliage, darkened under the snow, in the spring? The juicy soft green leaf blades rotted over the winter, and the more durable veins preserved and clearly visible.

Veins can also be seen on a living green leaf, especially if you hold the leaf up to the light. On the underside of the leaf blade the veins are more visible than on the top.

Water and substances dissolved in it move through the veins. The special fibers of the veins give the leaves strength and elasticity. The veins also contain sieve tubes, through which organic substances flow from the leaves to all organs of the plant.

In the leaves of some plants, the veins are located parallel to one another. This venation is called parallel. It is found in almost all monocotyledonous plants, such as wheat, rye, barley, corn, onions and some others.

The leaves of the lily of the valley and the houseplant aspidistra, or “friendly family,” havearc Venation.Arc venation, like parallel venation, is usually found in monocotyledonous plants.

Dicotyledonous plants often have palmate or pinnate venation.

In the case of pinnate venation, a large main vein runs through the middle of the leaf, and smaller lateral veins extend from it, like in oak. At fingered venation: several main veins of equal thickness diverge to the sides from the base of the leaf blade, like a maple, nasturtiums, cuffs and others. With fingering And pinnate venation veins can branch repeatedly And, connecting with each other, forming howl thick mesh. If the main veins are weakly expressed, then the venation is called pinnate-reticulate or finger-reticulate. Take a look on the leaves of maple, linden, apple tree or indoor plants such as geranium, lemon, begonia, primrose, rose. All these dicotyledonous plants have reticulate venation. Based on the venation, it is easy to decide which plant is in front of you: a monocotyledon or a dicotyledon. But there are exceptions. For example, In a monocot plant raven eye the leaves have reticulate veining.

There are plants in which flowers develop one at a time at the ends of the shoots or in the axils. These are single flowers. And other plants have flowers collected in inflorescences.

Inflorescence- This is a shoot of a plant that bears flowers and does not bear leaves.

Inflorescences there are simple And complex. Small flowers are usually collected in inflorescences, which makes them easily visible to pollinating insects.

Cabbage, lily of the valley, bird cherry have inflorescence brush. In such an inflorescence, individual flowers are located one after another on clearly visible pedicels extending from a long common axis.

Simple ear They form flowers without pedicels (that is, sessile), located on the common axis of the inflorescence, like those of plantain. Inflorescences of wheat, rye, barley are called complex ear. In this inflorescence, several spikelets sit on a common axis, each of which is formed by several flowers (in rye, for example, two).

cob differs from the spike by the thick, usually fleshy axis of the inflorescence.

Simple umbrella- an inflorescence in which the pedicels extend from the top of the inflorescence axis. Primrose has such an inflorescence.

The inflorescence is a simple umbrella. Example -

Simple inflorescences can be grouped into complex inflorescences. Carrots and parsley have umbrella inflorescences, consisting of several simple umbrellas. This inflorescence is called complex umbrella.

And I would like to start this chapter with a quote from Ursula de Guin’s book “A Wizard of Earthsea”:

Tell me, what is this plant near the path?
- Immortelle.
- And that one over there?
- Don't know.
- It's called a quatrefoil. - Ogion stopped and pointed the copper-bound tip of his staff at the inconspicuous weed. Ged examined it carefully, took the dried pod and, seeing that Ogion was not going to say anything more, asked:
- What is the use of it, Master?
- None, as far as I know.
They walked on, and Ged soon threw the pod away.
- When you recognize the quatrefoil in all seasons by its root, by its leaf and by its flower, by its appearance, by its smell and by its seed, only then will you be able to learn to pronounce its real Name. And this is more than knowing what benefits it brings.

At one time I was lucky, and one professor of Botany taught me to understand how important it is to be able to distinguish herbs by appearance. All of you in ordinary schools took Botany lessons and were taught that plants are divided into classes - dicotyledons and monocotyledons, which in turn are divided into families, and families into genera. We won't go deep into botany. I will try to remind you only of what will help you determine what kind of plant is in front of you.

What characteristics catch your eye first?

Naturally, you need to start with what is in front of you: plants with woody stems (trees, shrubs, woody vines) or grasses, that is, plants with non-woody stems.
Let me remind you that:
Trees are usually large plants with perennial woody stems. Every tree has a trunk and branches. Tree branches form their crowns (oak, linden, poplar, aspen, birch, and so on).
In growth, the shrub can be like a small tree, but its trunk begins almost at the very surface of the soil and is difficult to recognize among the branches. Therefore, shrubs do not have one trunk, like trees, but several trunks extending from a common base (elderberry, hazel, lilac).
Grasses are plants with non-woody stems. Usually they always have green and succulent stems. The size of herbs can be very different - from microscopic (duckweed reaches only a few millimeters) to very large (a banana, which is a grass, can reach 7 meters, and hogweed easily grows taller than human height.)
Both trees and shrubs are perennials. The lifespan of some trees, such as oaks, can reach thousands of years.
Herbs can be annual (born from a seed, go through a full cycle in a year and, after the formation of fruits with seeds, die; these are violets, radishes, wheat), biennial (in the first year roots, stems and leaves develop, in the second year the plants bloom, bear fruit and die; these are beets, radishes, cabbage) and perennial (roots and other underground organs with buds live quite a long time, the above-ground part of the plant goes through a cycle every year, growing in the spring and dying in the fall; these are nettles, dandelions, coltsfoot) .

After determining what exactly is in front of us, grass or tree, we move on to studying the leaf.

The leaf is part of the shoot. Externally, the leaves of different plants vary greatly, but they have a lot in common. The leaves of most plants are green in color and consist of a leaf blade and a petiole, which connects them to the stem.

It would not be amiss to remember the veins - the blood vessels of the plant. The forms of venation differ in appearance. You will immediately understand what kind of veining a leaf has as soon as you see it. It can be parallel, arc and mesh.
Parallel veining is found in monocotyledonous plants, for example, cereals. Such veining can be found in sedge or wheat, in some types of palm trees and in daffodils. Arc venation can be found in plantain or lily of the valley. Well, reticulate venation is very typical for tree leaves, as well as for all dicotyledons.

The leaves can be needle-shaped (coniferous), scale-shaped (Peter's cross) or another shape - simple or complex.
If there is one leaf blade on the petiole (linden, maple), the leaf is called simple. A leaf consisting of several leaf blades connected to a common petiole by small petioles is called compound (strawberry, chestnut, acacia). In such leaves, each blade usually falls off independently of the others. Simple and complex leaves, in turn, are also divided into groups:

Simple leaves:

• Palmately dissected (meadow geranium)
• Palmate (maple)
• Palmate (cuff)
• Pinnate (oak)
• Pinnately dissected (marigolds)
• Pinnately (meadowsweet)

Compound leaves:

• Trifoliate (strawberry)
• Palmate (chestnut)
• Paripirnate (rowan, ash)
• Imparipinnate (acacia)
• Double-digital (mimosa)

In herbaceous plants, it is worth paying attention to the root. The root system is divided into two parts - taproot and fibrous. Even by the name it is already easy to understand how to distinguish them.
The easiest thing to understand is carrots. This is a prime example of a tap root. And those mini-roots that extend from the main root (the carrot itself) are called lateral roots. If you carefully dig up a dandelion, you will see its main, pronounced root in the form of a rod and a bunch of small lateral roots on it. It is too typical example rod system.
Sometimes additional roots emerge from the stems and leaves, which are quite weak compared to the main one. They are called subordinate clauses. In two-year-olds and perennial plants in the second year of life, the main root dies off, and the plant lives off the adventitious roots.
Now let’s pull the wheat out of the soil and study its roots. The main root is not visible... all the roots come from the stem, and they are approximately equal to each other. Each has additional small side roots. This is a typical representative of a plant with a fibrous root system.

Flowers:

You can find several definitions on the Internet that suggest starting to identify a flower with color. But here you should pay attention to the fact that sometimes the color differs from the generally accepted one. For example, if a plant normally blooms with pink and red flowers, there may also be individuals with white flowers, and plants with blue or light blue flowers sometimes have pink and whitish flowers.

• Correct (chamomile)
• Incorrect (mouse peas)
• Split leaf (onion, tulip)
• Double-lipped (sage)
• Compound-leaved and compound-petalled (asparagus)
• Calyx with undercup (mallow)

Inflorescences:

Inflorescences are groups of flowers located close to one another in a certain order. They can be simple or complex. Usually small flowers are collected in inflorescences, since insects are more likely to notice a large grouped flower than a small single one.
Depending on the type of branching, the length and location of the axes of the inflorescence and the sequence of flower initiation, many inflorescences are distinguished, for example:

• The raceme - the main axis has an indefinitely long growth, and flowers are laid on it, approximately equal in length to the peduncle (mine bifolia).
• Umbrella - the internodes of the main axis are shortened so that all the pedicels emerge as if from one point (a simple umbrella is a cherry, a complex one is a carrot).
• The ear differs from the ear by the thick, usually fleshy axis of the inflorescence (calamus).
• The head - the main axis is shortened and somewhat widened, the flowers are sessile or on short stalks, collected in a compact inflorescence (clover).
• Simple spike - formed by flowers without pedicels (that is, sessile), located on the common axis of the inflorescence, like a plantain.
• The inflorescences of wheat, rye, and barley are called compound ears. In this inflorescence, several spikelets sit on a common axis, each of which is formed by several flowers.
• The basket - the main axis is saucer-shaped and has sessile flowers located on it, opening from the edges to the center; on the outside, the basket is surrounded by apical leaves that are moved towards it, forming the so-called involucre (umbrella hawkweed).
• Dichasia is a complex inflorescence in which two branches (opposite or alternate) appear below the terminal flower on the main axis of the inflorescence, ending in flowers and sometimes in turn also branching (on the left). Dikhasia is often called a half-umbrella (buckthorn).

In nature, there are other types of complex inflorescences, which are a combination of inflorescences of the same or different types. Examples of complex inflorescences, in addition to dichasia, are: a complex umbrella (left), a complex spike, a panicle, a head of baskets (right). Biological features carrots

Basically, long root vegetables reach sizes up to 15 cm, medium ones 11-15 cm, and short ones less than 10 cm.

In our country, you can rarely see root vegetables whose size exceeds 30-40 cm, but it is known that in Mexico the size of carrots grown can be higher than these parameters.

Root crops with a diameter of less than 2.5 cm fall into the thin group, from 2.6 to 4 cm into the medium group, and more than 4 cm into the thick group.

Depending on the variety and growing conditions, their weight can reach: small less than 80 g, medium 80-150 g, and large more than 150 g.

In an area where the soil is loose and fertile, the mass of root crops can reach 300–500 g or more.

The most common varieties of carrots have orange, red-orange, pink-orange and red root colors, although very rarely you can also find varieties with purple, yellow, white, and light green colors.

The surface of root vegetables can be lumpy, uneven and smooth. You can also notice deep or small eyes on them. The root vegetable itself is fleshy. It has a brighter color compared to the core, although it is rare, but there are varieties (for example, Nantekii-4) in which the core and bark are equally bright in color.

The shape of the core can be clearly seen if the root crop is cut transversely. It can be star-shaped, faceted, round and rounded-angular in shape.

Root crops with a small core size are those in which it is less than 30% in diameter, with an average 30-50% and with a large one more than 50%.

The rosette leaves of carrots are simple. The shape of the plate contour is triangular or rhombic.

Rosettes of leaves can be appressed, spreading or semi-erect.

Leaf cuttings can be bare, thin, long or pubescent, with a light green color.

Green plates, Asian forms, are also dark green in color, often gray-green.

As mentioned earlier, you can see how this crop blooms in its second year.

At the beginning of flowering, the stem can reach a height of 1 m. The stems themselves are ribbed, arched, pubescent or bare, branched with a green or yellow-green color.

Each stem has an inflorescence in the shape of a complex umbrella, on which there are individual small umbrellas. On most plants, the flowers are small and bisexual, but they are rarely found with a male sterile form.