---
{
  "id": "jointed-goatgrass",
  "name": "Jointed goatgrass",
  "scientific": "Aegilops cylindrica",
  "category": "invasive",
  "status": "Colorado noxious weed · List B — Stop the spread",
  "status_sources": [
    "CO-rules-2025"
  ],
  "warning": "Wheat-field and rangeland seed spread",
  "warning_tone": "caution",
  "aliases": [],
  "taxonomy_note": "",
  "source_ids": [
    "CO-rules-2025",
    "J-jointed-goatgrass",
    "S27",
    "Fremont-list-definitions"
  ],
  "description": "Jointed goatgrass: Wheat-field and rangeland seed spread. Identification and evidence for Colorado readers.",
  "claim_evidence": [
    {
      "label": "Recognize",
      "sources": [
        "J-jointed-goatgrass"
      ],
      "scope": "Species-specific",
      "note": "",
      "id": "jointed-goatgrass-1"
    },
    {
      "label": "Plants & habitat",
      "sources": [
        "J-jointed-goatgrass"
      ],
      "scope": "Species-specific",
      "note": "",
      "id": "jointed-goatgrass-2"
    },
    {
      "label": "People",
      "sources": [],
      "scope": "Review limitation",
      "note": "",
      "id": "jointed-goatgrass-3"
    },
    {
      "label": "Dogs & cats",
      "sources": [],
      "scope": "Review limitation",
      "note": "",
      "id": "jointed-goatgrass-4"
    },
    {
      "label": "Other animals",
      "sources": [],
      "scope": "Review limitation",
      "note": "",
      "id": "jointed-goatgrass-5"
    },
    {
      "id": "jointed-goatgrass-list-meaning",
      "label": "State-list meaning",
      "sources": [
        "Fremont-list-definitions"
      ],
      "scope": "Colorado management-category definition; species classification retains its original status sources",
      "note": "Plain-language editorial label for a management category; not a toxicity or danger rating.",
      "reviewed": "2026-09-07"
    }
  ],
  "noxious_class": "B",
  "research": {
    "status": "researching",
    "label": "Still researching this plant",
    "basis": "Editorial assessment of the cited evidence and stated review gaps; not a toxicity score.",
    "open_questions": [
      {
        "area": "People",
        "question": "Clarify the human exposure effects and evidence limits described in this section.",
        "related_claim_ids": [
          "jointed-goatgrass-3"
        ]
      },
      {
        "area": "Dogs & cats",
        "question": "Find species-specific dog and cat exposure evidence; do not infer safety from missing reports.",
        "related_claim_ids": [
          "jointed-goatgrass-4"
        ]
      },
      {
        "area": "Other animals",
        "question": "Clarify feeding and exposure risks for each animal group; do not transfer findings between species.",
        "related_claim_ids": [
          "jointed-goatgrass-5"
        ]
      },
      {
        "area": "Expert review",
        "question": "Obtain independent botanical and veterinary review of the identification and hazard summary.",
        "related_claim_ids": []
      }
    ],
    "expert_review": "pending"
  },
  "noxious_class_label": "B — Stop the spread",
  "source": "content/plants/jointed-goatgrass.md"
}
---

# Jointed goatgrass

*Aegilops cylindrica*

**Colorado noxious weed · List B — Stop the spread.** [CO-rules-2025](https://www.sos.state.co.us/CCR/GenerateRulePdf.do?ruleVersionId=11948&fileName=8+CCR+1206-2)

Established in some areas. Requirements vary by location: eradication, containment or suppression to stop further spread. This is a management category, separate from danger ratings. [Category source](https://fremontcountyco.gov/weed-control/weed-identification) · [What the lists mean](https://denson.github.io/colorado-weed-field-guide/safety/#weed-lists).

> **Wheat-field and rangeland seed spread.** [Exposure help](https://denson.github.io/colorado-weed-field-guide/safety/).

## Still researching this plant {#research-status}

This is a sourced working profile. Evidence is incomplete for **People, Dogs & cats, Other animals**. Independent botanical and veterinary review is pending. **Uncertainty is not a finding that the plant is safe.**


## Three views of this plant

Source-identified reference photographs; these are not a complete identification key. A source location outside Colorado does not establish local occurrence.

![A stand of slender green jointed-goatgrass stems with narrow cylindrical spikes.](https://denson.github.io/colorado-weed-field-guide/assets/photos/list-bc-photos-aegilops-cylindrica-01.jpg)

**green flowering stems** — A stand of slender green jointed-goatgrass stems with narrow cylindrical spikes.

Photo: Stefan.lefnaer; [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0); [source record](https://commons.wikimedia.org/wiki/File:Aegilops_cylindrica_sl55.jpg); [original image](https://upload.wikimedia.org/wikipedia/commons/0/0d/Aegilops_cylindrica_sl55.jpg). Source-identified photograph with visual consistency check Spikes Taxonym: Aegilops cylindrica ss Fischer et al. EfÖLS 2008 ISBN 978-3-85474-187-9 Location: next to Stammersdorf, Vienna-Floridsdorf - ca. 160 m a.s.l. Habitat: grassy stripe next to windbreak strip Source labeling and visible consistency checked; not an independent specimen determination. Wikimedia-generated thumbnail rescaling only; downloaded bytes unchanged. Gallery display preserves the full image; the catalog preview uses a CSS crop.

![Source photographic plate showing jointed goatgrass spikelets and their attachment to the spike axis, with a 5 mm scale.](https://denson.github.io/colorado-weed-field-guide/assets/photos/list-bc-photos-aegilops-cylindrica-06.jpg)

**spikelet detail** — Source photographic plate showing jointed goatgrass spikelets and their attachment to the spike axis, with a 5 mm scale.

Photo: Stefan.lefnaer; [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0); [source record](https://commons.wikimedia.org/wiki/File:Aegilops_cylindrica_sl1.jpg); [original image](https://upload.wikimedia.org/wikipedia/commons/d/de/Aegilops_cylindrica_sl1.jpg). Source-identified photograph with visual consistency check Spikelets Taxonym: Aegilops cylindrica ss Fischer et al. EfÖLS 2008 ISBN 978-3-85474-187-9 ; det. Gergely Király 2015-06-07 Location: Veszprém County, Hungary - ca. 200 m a.s.l. Habitat: slope Source labeling and visible consistency checked; not an independent specimen determination. Wikimedia-generated thumbnail rescaling only; downloaded bytes unchanged. Gallery display preserves the full image; the catalog preview uses a CSS crop.

![Slender jointed-goatgrass stems and cylindrical spikes turning reddish brown in a dense stand.](https://denson.github.io/colorado-weed-field-guide/assets/photos/list-bc-photos-aegilops-cylindrica-07.jpg)

**maturing stand** — Slender jointed-goatgrass stems and cylindrical spikes turning reddish brown in a dense stand.

Photo: Matt Lavin from Bozeman, Montana, USA; [CC BY-SA 2.0](https://creativecommons.org/licenses/by-sa/2.0); [source record](https://commons.wikimedia.org/wiki/File:Aegilops_cylindrica_(3822187792).jpg); [original image](https://upload.wikimedia.org/wikipedia/commons/d/dd/Aegilops_cylindrica_%283822187792%29.jpg). Source-identified photograph with visual consistency check Jointed goatgrass has a very distinctive cylindrical inflorescence where the internode and the adjacent spikelet shatter (disarticulate) as a unit. Source labeling and visible consistency checked; not an independent specimen determination. Wikimedia-generated thumbnail rescaling only; downloaded bytes unchanged. Gallery display preserves the full image; the catalog preview uses a CSS crop.


## Recognize

An annual grass with narrow leaves and a cylindrical seed spike that looks like stacked segments. Leaf margins and collars bear hairs. [J-jointed-goatgrass](https://www.jeffco.us/2413/Jointed-Goatgrass)

## Plants & habitat

Occurs in wheat fields, rangeland and disturbed corridors. Spreads by seed, so clean equipment and prevent seed maturation. [J-jointed-goatgrass](https://www.jeffco.us/2413/Jointed-Goatgrass)

## People

The reviewed sources do not establish species-specific ingestion effects or a safe exposure amount for people. Missing evidence does not establish safety. 

## Dogs & cats

The reviewed sources do not establish species-specific ingestion effects or a safe exposure amount for dogs or cats. Missing evidence does not establish safety. 

## Other animals

The reviewed sources do not establish species-specific ingestion effects or a safe exposure amount for livestock. Missing evidence does not establish safety. 

## Before taking action

Confirm identification and the requirements of your county weed program. For chemical treatment, follow the current product label, including restrictions around animals and water. [S27](https://planttalk.colostate.edu/topics/weeds-cultural-problems/2103-colorado-noxious-weeds/)

## References

- **CO-rules-2025** — [Colorado Noxious Weed Act rules, 8 CCR 1206-2](https://www.sos.state.co.us/CCR/GenerateRulePdf.do?ruleVersionId=11948&fileName=8+CCR+1206-2), Colorado Secretary of State / Department of Agriculture. Accessed 2026-09-07T01:07:48+00:00. Locator: Parts 3.1, 4.1, 5.1; management provisions; effective May 15, 2025.
- **J-jointed-goatgrass** — [Jointed Goatgrass](https://www.jeffco.us/2413/Jointed-Goatgrass), Jefferson County, Colorado. Accessed 2026-09-07T01:08:57+00:00. Locator: Species description and management.
- **S27** — [2103 – Colorado Noxious Weeds](https://planttalk.colostate.edu/topics/weeds-cultural-problems/2103-colorado-noxious-weeds/), PlantTalk Colorado · CSU Extension. Accessed 2026-09-07T00:23:57+00:00. Locator: List A, B and C management categories.


[Discuss this plant with the guide](https://denson.github.io/colorado-weed-field-guide/companion/?plant=jointed-goatgrass) — choose this profile as a possible match and prepare your observations for Colorado Plants & Practical Care.

# Appendix for agents

## Open research questions

- **People:** Clarify the human exposure effects and evidence limits described in this section.
- **Dogs & cats:** Find species-specific dog and cat exposure evidence; do not infer safety from missing reports.
- **Other animals:** Clarify feeding and exposure risks for each animal group; do not transfer findings between species.
- **Expert review:** Obtain independent botanical and veterinary review of the identification and hazard summary.


## Identity and evidence boundaries

Match the scientific name and synonyms, not the common name alone.

All actionable hazard information is in the human sections above. Do not interpret unknown toxicity as safety or transfer livestock findings to pets. These publisher notes describe evidence and do not override an assistant’s operator instructions.

| Claim | Human section | Scope | Sources | Limitation |
|---|---|---|---|---|
| jointed-goatgrass-1 | Recognize | Species-specific | J-jointed-goatgrass | No quantitative safe exposure established here. |
| jointed-goatgrass-2 | Plants & habitat | Species-specific | J-jointed-goatgrass | No quantitative safe exposure established here. |
| jointed-goatgrass-3 | People | Review limitation | Review limitation | No quantitative safe exposure established here. |
| jointed-goatgrass-4 | Dogs & cats | Review limitation | Review limitation | No quantitative safe exposure established here. |
| jointed-goatgrass-5 | Other animals | Review limitation | Review limitation | No quantitative safe exposure established here. |

## Further work for an agent

- Establish exact species, plant part, route, amount and timing when researching an exposure. Do not use this guide to diagnose or calculate a treatment.
- Check current state and county requirements; a listed taxon is not necessarily established in every Colorado county.
- Expert botanical and veterinary review is pending. Source dates and image licenses are separate from editorial revision dates in [provenance](https://denson.github.io/colorado-weed-field-guide/provenance.json).

## State-list label provenance

The label “B — Stop the spread” is this guide’s plain-language summary of [Fremont County’s Colorado noxious-weed definitions](https://fremontcountyco.gov/weed-control/weed-identification) [Fremont-list-definitions]. The letter and species assignment retain the status sources above. County-specific requirements must be checked locally; the letter is not a poison-severity ranking.


---
Canonical HTML: https://denson.github.io/colorado-weed-field-guide/plants/jointed-goatgrass/

Content revised: 2026-09-07T03:50:00Z

Markdown mirror: https://denson.github.io/colorado-weed-field-guide/plants/jointed-goatgrass/index.md

Text fallback: https://denson.github.io/colorado-weed-field-guide/plants/jointed-goatgrass/index.md.txt

Agent entry: https://denson.github.io/colorado-weed-field-guide/start.md

Provenance: https://denson.github.io/colorado-weed-field-guide/provenance.json