Meaning & use
indusium
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Meanings
nouncountablebiologytechnical
A thin scale-like covering that protects a cluster of spore cases on the underside of a fern leaf.
Grammar: Has the plural indusia: each indusium covers one sorus.
Patterns
- the indusium of a fern
- the indusium covers something
Under a hand lens, the indusium looks like a tiny shield over the spores.
The shape of the indusium helps botanists identify the fern.
In some species, the indusium shrivels as the spores ripen.
nouncountablemedicaltechnical
In anatomy, a thin layer of grey matter lying on the corpus callosum of the brain, known as the indusium griseum.
Grammar: Usually appears in the phrase indusium griseum.
Patterns
- indusium griseum
The indusium griseum is a thin strip of tissue above the corpus callosum.
A neuroanatomy text describes the indusium in a single short paragraph.
Word forms
| plural | indusia |
|---|
Common combinations
- fern indusium
- The fern indusium splits open to release the spores.
- kidney-shaped indusium
- The species has a kidney-shaped indusium.
- indusium griseum
- Researchers studied the indusium griseum in mice.
- cover with an indusium
- Each cluster is covered with an indusium.
Synonyms and how they differ
Word family
- indusial adjective
- relating to an indusium
- sorus noun
- a cluster of spore cases on a fern
- indusiate adjective
- having an indusium (rare)
Commonly confused: indusium or sorus?
indusium vs sorus
The sorus is the cluster of spore cases itself, but the indusium is the thin cover that may protect it.
Practice
On the underside of the fern frond, the ____ protects the clusters of spore cases.
Choose one answer.
The indusium is the thin cover over the spore clusters. The sorus is the cluster itself, which is the thing being protected.
Make it your own
Write a sentence using “indusium”, then check it and compare it with the examples above.