# Bract

> In cannabis, the small leaf-like sheath (perigonal bract) that wraps each female flower's ovary and carries the densest capitate-stalked trichomes.

- Canonical: https://genetixbay.com/knowledge/glossary/bract.html
- Also written: perigonal bract, bracts, floral bract, pistillate bract, seed bract
- Glossary category: Plant biology · Evidence: Established
- 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"

A bract is a modified leaf associated with a flower. In female cannabis, each [pistillate flower](https://genetixbay.com/knowledge/glossary/pistillate-flower.md) is enclosed by a perigonal bract: a small, cupped, green structure that wraps the ovary and from which the [stigmas](https://genetixbay.com/knowledge/glossary/stigma.md) protrude. The bract swells as the flower matures and, if pollinated, encloses the developing seed. Bracts carry the highest density of [capitate-stalked](https://genetixbay.com/knowledge/glossary/capitate-stalked-trichome.md) glandular [trichomes](https://genetixbay.com/knowledge/glossary/trichome.md) on the plant.

## In practice

What growers call "calyxes" or "calyx-to-leaf ratio" are, botanically, bracts. A "high calyx-to-leaf ratio" means many swollen bracts and few [sugar leaves](https://genetixbay.com/knowledge/glossary/sugar-leaf.md), which makes trimming easy and puts more resin into the bud. Bract swelling in late flower is one of the visual ripeness signs, alongside [trichome colour](https://genetixbay.com/knowledge/glossary/trichome-ripeness.md).

Because bracts are where most resin sits, the share of a dried bud's mass that is bract (and trichome) rather than stem and leaf sets a hard ceiling on what flower can test.

## Don't confuse with

- **Calyx**: the true calyx is a thin, reduced perianth on the ovary, barely visible; growers use the word for the bract.
- **Sugar leaf**: a small [true leaf](https://genetixbay.com/knowledge/glossary/true-leaves.md) among the flowers.
- **Pistil**: the female reproductive organ inside the bract.

## Related terms

[Calyx](https://genetixbay.com/knowledge/glossary/calyx.md), [Pistil](https://genetixbay.com/knowledge/glossary/pistil.md), [Capitate-stalked trichome](https://genetixbay.com/knowledge/glossary/capitate-stalked-trichome.md), [Cola](https://genetixbay.com/knowledge/glossary/cola.md), [Achene](https://genetixbay.com/knowledge/glossary/achene.md)

## Read more

- [Cannabis plant biology: the parts and what they do](https://genetixbay.com/knowledge/basics/cannabis-plant-biology.md)
- [Trichome ripeness: clear, cloudy, amber, and what the evidence says](https://genetixbay.com/knowledge/harvest-cure/trichome-ripeness.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. Livingston SJ, Quilichini TD, Booth JK, et al. 2020. Cannabis glandular trichomes alter morphology and metabolite content during flower maturation. The Plant Journal 101(1):37-56. https://doi.org/10.1111/tpj.14516
3. 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