The phrase "a certain plant" is correct and usable in written English.
It can be used when referring to a specific plant without naming it directly, often in a context where the identity of the plant is either unknown or not important to the discussion.
Example: "In the garden, I noticed a certain plant that had vibrant flowers, but I couldn't identify it."
Alternatives: "a specific plant" or "a particular plant".
"If I want a certain plant, I'll get it, unless it costs thousands of dollars.
The archaeologists suggest that people begin domesticating a plant not necessarily to increase yield, as Near Eastern farmers did, but because they want to be sure to have a certain plant when they want it -- either for some ritual use or just because they like it.
Each spring, he hosts a conference for 100 local traditional forecasters, each of whom presents a monsoon prediction with supporting evidence the behaviour of a species of bird, strong flowering in a certain plant, or the prevailing wind direction that season.
On the other hand, I may be able to say something about the relationship of herbivores to a certain plant of interest.
Furthermore, product names and ingredient lists often do not match: Three products named after a certain plant did not indicate names of these plants in the ingredient lists.
A certain plant configuration was contemplated, equipped with an external steam reformer, an afterburner, a mixer and two heat exchangers (preheaters).
Therefore, it is likely that host molecular response is specific for a certain plant-aphid interaction.
A new study has found that nocturnal caterpillars called Mythimna separate spring to life each evening when they get a whiff of certain plant scents.
The first factor determining optimal defense is risk: how likely is it that a plant or certain plant parts will be attacked?
Viroid, an infectious particle smaller than any of the known viruses, an agent of certain plant diseases.
It may proceed either via the direct action of a triacylglycerol lipase, or in certain plant species via a specific lipid body 13-lipoxygenase.
