Lenticels are small, raised pores on woody stems and other woody plant parts that allow gas exchange. In Intro to Botany, they explain how bark-covered stems keep living tissues supplied with oxygen.
Lenticels are the little bumps or corky spots you see on the bark of many woody plants. In Intro to Botany, they are the stem structures that let gases move between the inside of the plant and the air outside when the stem surface is too sealed up for normal gas exchange.
Their main job is simple: let oxygen diffuse in and carbon dioxide diffuse out. Living stem tissues still respire all the time, even when the plant is not photosynthesizing. That means cells inside a thick stem need a steady gas supply, especially after bark has formed and covered the outer surface.
Lenticels are made from loosely packed parenchyma cells with air spaces between them. Those gaps make diffusion easier than it would be through dense, compact tissue. Instead of acting like a closed wall, the lenticel region stays more open and porous, so gases can move through the bark layer.
You usually find lenticels on woody stems, branches, and sometimes on roots or fruits, depending on the species. They are often more noticeable on younger woody stems and can appear as tiny raised dots, spots, or stripes. Their size, shape, and number vary by plant species, and they can also shift with growing conditions such as humidity and temperature.
The reason lenticels matter becomes clearer when you compare them with stomata. Stomata work well on green, younger plant surfaces, but bark gets thicker as secondary growth adds more protective tissue. Once that outer covering is in place, lenticels become the plant's backup pathway for gas exchange. If you are looking at a woody twig in lab, those little raised marks are one of the easiest signs that the stem still has living tissue underneath the bark.
A common mistake is thinking lenticels are just a surface texture. They are actually functional openings in the bark. If a stem has a lot of bark damage, the plant can lose efficient gas exchange, which is one reason these structures matter in woody plants that keep growing for years.
Lenticels matter in Intro to Botany because they connect stem anatomy to plant physiology. A woody stem is not just a hard support structure, it is still alive inside, and those internal cells need oxygen for respiration. Lenticels show how plants solve that problem after bark develops and the surface becomes too sealed for stomata to do the job.
They also help you see the link between structure and function. As stems undergo secondary growth, the outer bark thickens and protective tissues take over, but gas exchange still has to continue. Lenticels are one of the clearest examples of an adaptation that appears because another tissue, bark, creates a new limitation.
In lab or lecture, lenticels are useful for identifying woody stems and for comparing young green stems with older woody ones. If you can explain why a stem surface has raised pores, you are showing that you understand not just what the structure is, but what problem it solves inside the plant.
Keep studying Intro to Botany Unit 1
Visual cheatsheet
view galleryStomata
Stomata and lenticels both allow gas exchange, but they work in different places and under different conditions. Stomata are found mostly on leaf surfaces and young green stems, while lenticels are associated with bark-covered woody stems. If a question asks why a woody stem still exchanges gases after bark forms, lenticels are the structure to name.
Bark
Bark is the outer protective covering of woody stems, and it is the reason lenticels become necessary. As bark thickens, it blocks ordinary surface diffusion. Lenticels interrupt that barrier with small porous areas, so the stem can protect itself without cutting off gas exchange to living tissues underneath.
secondary growth
Secondary growth thickens stems and produces the woody tissues that eventually need lenticels. As the stem expands, the outer layers become less permeable to gases. Lenticels are part of the plant's response to that growth pattern, making them a good example of how anatomy changes as a stem matures.
woody stem
Woody stems are the main place you notice lenticels, because they develop bark and long-term protective tissues. A herbaceous stem usually does not need the same kind of gas exchange openings in bark. If you are comparing stem types, lenticels are a clear marker of a woody stem that has shifted into long-term structural growth.
A quiz question might show a photo of a twig and ask you to identify the raised dots on the bark. The move is to name them as lenticels and explain that they allow gas exchange in woody stems. In a short answer, you may also need to connect them to respiration, bark, or secondary growth. If the prompt compares stem surfaces, pick lenticels when the structure is on a woody, bark-covered stem and stomata when the surface is green and more exposed. In a lab practical, look for small corky openings that stand out from the surrounding bark.
Stomata are tiny adjustable pores mainly on leaves and young stems, while lenticels are fixed openings in the bark of woody stems. Both move gases, but stomata can open and close with guard cells, and lenticels are usually more open and less tightly regulated. If the plant part is woody and bark-covered, think lenticel.
Lenticels are small raised pores on woody stems that let oxygen and carbon dioxide move between internal tissues and the atmosphere.
They matter because bark thickens during secondary growth and blocks gas exchange through the stem surface.
Lenticels are made of loosely packed cells with air spaces, which makes diffusion easier.
They are easy to spot on twigs and branches as tiny bumps, dots, or corky marks in the bark.
If you are comparing them with stomata, remember that lenticels belong to woody bark-covered stems, not mainly to leaf surfaces.
Lenticels are small pores in the bark of woody plants that let gases move in and out of the stem. In Intro to Botany, they are the stem adaptation that keeps living tissues supplied with oxygen after bark gets too thick for normal surface exchange.
No. They both handle gas exchange, but stomata are mainly on leaves and green stems and can open or close with guard cells. Lenticels are found in bark on woody stems and are usually more permanently open structures.
You usually find lenticels on woody stems and branches, and sometimes on roots or fruits depending on the species. They are easiest to spot on bark as tiny raised dots, bumps, or corky spots.
Woody stems need lenticels because bark thickens during secondary growth and limits gas exchange through the surface. The cells inside the stem still respire, so the plant needs a pathway for oxygen in and carbon dioxide out.