# Calyx

> Botanically, the sepals of a flower; in female cannabis a thin, reduced perianth on the ovary, though growers use the word for the resinous bract.

- Canonical: https://genetixbay.com/knowledge/glossary/calyx.html
- Also written: calyxes, calyces, perianth, calyx-to-leaf ratio
- Glossary category: Plant biology
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

In botany the calyx is the outer whorl of a flower, made of its sepals. In female cannabis the true calyx (perianth) is reduced to a thin, translucent membrane hugging the ovary, hard to see without magnification. The plump, resin-covered green pod growers point at and call a "calyx" is in fact the [perigonal bract](https://genetixbay.com/knowledge/glossary/bract.md) that surrounds it.

## In practice

The grower usage is everywhere and isn't going anywhere: "calyx-to-leaf ratio", "[foxtailing](https://genetixbay.com/knowledge/glossary/foxtailing.md) calyxes", "stacked calyxes". Read it as "bract". A high ratio means buds built mostly of swollen bracts with little leaf, which trims fast and carries more resin per gram.

Being precise matters in breeding notes and plant descriptions. A [GB-ID](https://genetixbay.com/knowledge/glossary/gb-id.md) record or a test guideline should say "bract" for the structure that carries the resin. Botanical papers on cannabis flower development (e.g. Spitzer-Rimon et al. 2019) use the correct terms, which makes them easier to read once you know.

## Don't confuse with

- **Bract**: the leafy sheath around the flower that growers usually mean.
- **Pistil**: the ovary, style and [stigmas](https://genetixbay.com/knowledge/glossary/stigma.md); the calyx surrounds the ovary.
- **Sugar leaf**: a small [true leaf](https://genetixbay.com/knowledge/glossary/true-leaves.md), not part of the flower.

## Related terms

[Bract](https://genetixbay.com/knowledge/glossary/bract.md), [Pistil](https://genetixbay.com/knowledge/glossary/pistil.md), [Stigma](https://genetixbay.com/knowledge/glossary/stigma.md), [Sugar leaf](https://genetixbay.com/knowledge/glossary/sugar-leaf.md)

## Read more

- [Cannabis plant biology: the parts and what they do](https://genetixbay.com/knowledge/basics/cannabis-plant-biology.md)

## Sources

1. Spitzer-Rimon B, Duchin S, Bernstein N, Kamenetsky R. 2019. Architecture and florogenesis in female Cannabis sativa plants. Frontiers in Plant Science 10:350. https://doi.org/10.3389/fpls.2019.00350
2. Small E. 2015. Evolution and classification of Cannabis sativa (marijuana, hemp) in relation to human utilization. The Botanical Review 81:189-294. https://doi.org/10.1007/s12229-015-9157-3