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Glossary of plant terms

Search our dictionary of 3,300 botanical and plant-related terms – the largest online.
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Latin name honouring G.Jackman.


Means "Japanese" in Latin.

John Innes compost

A range of sterile loam-based composts for use in germination, potting on and general use. Its name comes from the horticultural research institute that developed the compost formulae. The composts generally include loam and some clay enabling controlled release of nutrients, sand for structure and sphagnum moss for water conditioning. Also included are macronutrients and micronutrients.


Means "maned" or "awned" in Latin.


Refers to a pair of opposite leaves.


Means "downy" in Latin.


Means "rush-like" in Latin.

Juniper aphids

Leaves and stems become coated with black, sooty moulds. Heavy attacks cause yellowing and die-back in mid-late summer.


Means "juniper-like" in Latin.

Juniper scale

Flat, white objects develop on foliage. Heavy infestations cause yellowing and die-back of green shoots.

Juniper webber moth

Patched of brown foliage bound with silk webbing develop binding foliage. Leaves damaged many die in summer. Older junipers are more severely affected. Brown caterpillars may be found amongst the webbed foliage.


Means "of the Jura Mountains, France" in Latin.

Jurassic period

A period of time in the Earth's development 145 to 210 million years ago. A warm climate existed over much of the planet and there was a rich flora and fauna; notably pteridosperms (members of the division Pteridophyta) and dinosaurs (cold-blooded reptile-like creatures) evolved. Early bird-like creatures appeared.


This is a fibre used for weaving which is derived from the corchorus plant.


Refers to a young, immature organ or organism.

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