What Is a Leaf Lamina? The Flat Blade of a Leaf
A lamina is the leaf blade, the flat expanded part of a leaf. The Minnesota DNR glossary defines lamina as the leaf blade, while NC State Extension notes the blade is the thin structure on either side of the midrib plus is usually the largest part of the leaf.
The short answer
The lamina is the blade. NC State Extension notes it is the expanded, thin part on either side of the midrib. A stalk called the petiole holds it away from the stem plus attaches at the node. Colorado State notes the blade shape, margin, tip plus base all help with plant ID.
What is the lamina of a leaf?
Colorado State University Extension lists the leaf blade as the flattened part of the leaf, the petiole as the leaf stalk plus stipules as leaf like parts at the base. The Minnesota DNR glossary uses lamina for the blade as distinct from the midrib plus border.
What are the parts of the leaf blade?
NC State notes the midrib runs down the center, plus the blade spreads out to either side. Its edge is the margin. NC State notes the blade has several tissue layers inside.
| Part | What it is | Source |
|---|---|---|
| Lamina | The leaf blade | Minnesota DNR |
| Midrib | Central vein of the blade | NC State |
| Margin | Edge of the blade | NC State |
| Petiole | Leaf stalk | Colorado State |
| Stipules | Leaf like parts at the base | Colorado State |
| Leaflet | One part of a divided blade | Iowa State |
Source: NC State Extension, Colorado State Extension, Iowa State Extension plus Minnesota DNR.
How does lamina shape help with plant ID?
NC State notes leaves, especially the shapes of their blades plus margins, are useful in identifying species plus cultivars. Iowa State University Extension notes a simple leaf has one undivided blade, while a compound leaf blade is divided into leaflets.
How to: step by step
- Choose a mature leaf.
- Find the petiole.
- Follow the midrib.
- Look at the flat blade.
- Check the margin.
- Note if it splits into leaflets.
Troubleshooting
No stalk: a sessile leaf. NC State notes the petiole can be lacking.
Several blades on one stalk: a compound leaf. Iowa State notes the blade is divided into leaflets.
Tiny parts at the base: stipules. Colorado State notes they sit at the leaf base.
For leaf parts see cannabis leaf anatomy plus cannabis nodes and internodes. Read companion plants when growing marijuana plus growing cannabis near trees. Kind Seed Co also stocks cannabis seeds.
Sources
- Extension Gardener Handbook, chapter 3: botany, NC State Extension
- Botany (CMG GardenNotes 120), Colorado State University Extension
- Mosses and liverworts of Minnesota illustrated glossary, Minnesota DNR
- Glossary of garden terms, Iowa State University Extension and Outreach
FAQ
Is the lamina the same as the leaf blade?
Yes. The Minnesota DNR glossary defines lamina as the leaf blade, which NC State Extension describes as the expanded part on either side of the midrib.
What is a petiole?
Colorado State University Extension notes the petiole is the leaf stalk. NC State notes its base attaches to the stem at the node.
What is a leaf margin?
The margin is the edge of the blade. NC State Extension notes blade shape plus margin are useful for identifying plants.
Why are some laminae divided into leaflets?
Iowa State University Extension notes a compound leaf blade is divided into several discrete parts called leaflets.
What is a sessile leaf?
NC State Extension notes the petiole can be lacking entirely, plus such a leaf is described as sessile or stalkless.
