На столе стоит белая ромашка.

Because на столе means on the table in the sense of location.

With на:

• на + accusative usually means motion toward a surface:
  положить на стол = to put onto the table
• на + prepositional usually means location on a surface:
  на столе = on the table

So in На столе стоит белая ромашка, the flower is already there, so Russian uses the prepositional case: столе.

Столе is the prepositional case singular of стол.

The basic form is:

• стол = table

After the preposition на when talking about location, Russian usually uses the prepositional case:

• на столе = on the table

This is a very common pattern:

• в доме = in the house
• на улице = on the street
• на столе = on the table

So the ending changes because the noun is no longer in its dictionary form; it is in the case required by the preposition and meaning.

This is a very common Russian way of speaking.

Russian often uses different verbs depending on the physical position of an object:

• стоять = to stand
• лежать = to lie
• висеть = to hang

So стоит is used for things seen as being in an upright position. A flower in a vase, for example, is naturally described as standing in Russian.

That does not always mean the same kind of literal standing as in English. It is just the normal Russian way to describe position.

So:

• На столе стоит ваза. = There is a vase on the table.
• На столе лежит книга. = There is a book lying on the table.

In this sentence, стоит sounds natural because the daisy is understood as upright.

Usually, no—not in the most natural version of this sentence.

Russian often omits a verb like there is in the present tense, or uses a more specific positional verb such as стоит, лежит, or висит.

So instead of saying:

• На столе есть белая ромашка

Russian more naturally says:

• На столе стоит белая ромашка

Есть can sometimes be used, but it often sounds more like emphasizing existence or availability rather than simply describing where something is. In everyday description, стоит is better here.

Because adjectives in Russian must agree with the noun they describe.

Ромашка is:

• feminine
• singular
• nominative

So the adjective must also be:

• feminine
• singular
• nominative

That gives:

• белая ромашка = white daisy / a white daisy

Compare:

• белый стол = white table (masculine)
• белая ромашка = white daisy (feminine)
• белое окно = white window (neuter)

The ending -ая on белая shows feminine singular nominative.

Ромашка is in the nominative case because it is the subject of the sentence.

The sentence is structured like this:

• На столе = on the table
• стоит = stands
• белая ромашка = a white daisy

So the thing doing the standing is ромашка, and subjects are normally in the nominative case.

It can mean either, depending on context.

In Russian, ромашка is often used for the familiar white flower with a yellow center, and in many learning contexts it is translated as daisy. But in some contexts it can also refer to chamomile, especially in herbal or botanical contexts.

In this sentence, белая ромашка is most naturally understood as a white daisy.

Russian has no articles.

English distinguishes between:

• a white daisy
• the white daisy

Russian usually leaves that distinction to context, word order, or the situation.

So:

• белая ромашка can mean a white daisy or the white daisy

You understand which one is meant from the context, not from an article.

No, Russian word order is fairly flexible.

На столе стоит белая ромашка is a very natural neutral sentence. It often presents the location first, then says what is there.

Other orders are possible, for example:

• Белая ромашка стоит на столе.
  This focuses more directly on the white daisy.
• Стоит белая ромашка на столе.
  Possible, but less neutral and more stylistically marked.

Even though the order can change, the cases still show the grammar clearly.

Only if the flower is being viewed as lying down, not upright.

Russian chooses the verb based on how the object is positioned:

• стоит = standing upright
• лежит = lying flat
• висит = hanging

So if a flower is in a vase or upright on the table, стоит is natural. If it has fallen over and is lying flat on the table, then лежит would make sense.

This is one area where Russian is more specific than English.

The main stress is:

• На столе́ стои́т бе́лая рома́шка.

Approximate pronunciation:

• na stuh-LYE stah-EET BYE-luh-ya ra-MASH-ka

A few useful notes:

• столе́ has stress on the last syllable
• стои́т has stress on -ит
• бе́лая has stress on the first syllable
• рома́шка has stress on the second syllable

Stress matters in Russian, so it is good to learn each word together with its stress.

A very literal breakdown is:

• На столе = on the table
• стоит = stands
• белая ромашка = white daisy

So, word-for-word, it is roughly:

• On the table stands a white daisy.

That is more formal or literary in English, but it helps show how the Russian sentence is built. The natural English translation is usually:

• There is a white daisy on the table.
• A white daisy is standing on the table. (more literal, less natural in English)