Plant Stem Charts For Botany Lessons

Quick Answer: Stem Charts are plant stem charts for botany lessons, illustrating the external features of stems, stem modifications such as tubers, rhizomes and tendrils, and the internal structure of dicot and monocot stems. They are about plant biology, not STEM education kits.

Nodes, Modifications and Vascular Bundles

A stem is recognised by its nodes, the points where leaves and buds arise, separated by internodes. Plant stem charts use this rule to explain why several unlikely-looking organs are stems: the potato tuber with its eyes (buds), the ginger rhizome with nodes and scale leaves, the onion bulb with its short disc-like stem, and the colocasia corm. Aerial modifications usually shown include the stem tendrils of grapevine and cucumber, the thorns of bougainvillea and the flattened green stem (phylloclade) of Opuntia.

Sectional sheets explain the difference between dicot and monocot stems. In a dicot stem such as sunflower the vascular bundles form a ring and are open, with cambium between xylem and phloem, so the stem can thicken by secondary growth and lay down annual rings. In a monocot stem such as maize the bundles are scattered through the ground tissue, each wrapped in a sheath and without cambium.

Specifications

Subject	Plant stem morphology and anatomy
Typical diagrams	Nodes and buds, underground and aerial modifications, T.S. of dicot and monocot stems, annual rings
Level	Middle school to college botany
Use	Morphology lessons, section-cutting practicals
Titles, size and finish	Confirm at enquiry

Care & Handling

When stems stand in coloured water for the xylem demonstration, keep the beakers on the bench, not on a shelf beneath the stem charts.
Hang the modification sheet beside a tray of real potato, ginger, onion and colocasia so students can match specimen to drawing.
File these charts under botany in the chart store so they are not mixed up with STEM, robotics or electronics posters.

Applications

Classifying vegetables such as potato, ginger, onion and colocasia as modified stems
Standing a celery stalk in coloured water to show the xylem
Teaching secondary growth and counting annual rings on a log slice
Identifying stem modifications in practical examinations

Why Choose LabEquip

Botany departments usually order stem charts with the Root Charts, because underground stems and storage roots are easily confused, and add the Leaf Charts to complete the vegetative organs. Orders go through the LabEquip contact page.

Frequently Asked Questions

How do you know a potato is a stem and not a root?

A potato has eyes, which are buds sitting in the axils of tiny scale leaves, and buds grow only on stems. When planted, the eyes sprout into new shoots. Roots have no nodes, buds or leaves.

What is the difference between a rhizome and a corm?

A rhizome, such as ginger or turmeric, grows horizontally underground with clear nodes and internodes. A corm, such as colocasia, is a short, swollen, upright underground stem that stores food.

How is a dicot stem different from a monocot stem in section?

A dicot stem has its vascular bundles arranged in a ring, with cambium that lets the stem thicken. A monocot stem has many bundles scattered through the ground tissue and no cambium, so most monocots do not thicken with age.

What are annual rings?

In woody dicot stems the cambium forms wide, pale wood in the growing season and narrow, dark wood when growth slows. Each pair makes one ring, so counting the rings on a trunk gives an estimate of the tree’s age.

How can students see water moving up a stem?

Stand a fresh celery stalk or balsam stem in water coloured with ink or food dye for a few hours. The dye rises through the xylem, and a thin cross-section shows the coloured vascular bundles.