Plate 1 figs. a–h · 8 separate observations
Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.
Native range 44 botanical countries
| Region | TDWG code | Continent |
|---|---|---|
| Alabama | ALA | NORTHERN AMERICA |
| Arkansas | ARK | |
| Connecticut | CNT | |
| Delaware | DEL | |
| District of Columbia | WDC | |
| Florida | FLA | |
| Georgia | GEO | |
| Illinois | ILL | |
| Indiana | INI | |
| Iowa | IOW | |
| Kentucky | KTY | |
| Louisiana | LOU | |
| Maine | MAI | |
| Maryland | MRY | |
| Massachusetts | MAS | |
| Mexico Central | MXC | |
| Mexico Northeast | MXE | |
| Michigan | MIC | |
| Minnesota | MIN | |
| Mississippi | MSI | |
| Missouri | MSO | |
| Montana | MNT | |
| New Hampshire | NWH | |
| New Jersey | NWJ | |
| New York | NWY | |
| Newfoundland | NFL | |
| North Carolina | NCA | |
| Nova Scotia | NSC | |
| Ohio | OHI | |
| Oklahoma | OKL | |
| Ontario | ONT | |
| Pennsylvania | PEN | |
| Prince Edward I. | PEI | |
| Québec | QUE | |
| Rhode I. | RHO | |
| South Carolina | SCA | |
| Tennessee | TEN | |
| Texas | TEX | |
| Vermont | VER | |
| Virginia | VRG | |
| Washington | WAS | |
| West Virginia | WVA | |
| Wisconsin | WIS | |
| Dominican Republic | DOM | SOUTHERN AMERICA |
Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.
Flowering 90 in flower of 103 examined
Peak flowering in Aug. Each bar is the share of Hydrogalium claytonii observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 90 of 103 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 5 months have fewer than 5 examined observations, so no proportion is drawn for them. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.cgje2x.
Where it actually grows measured, from 542 observations
| Condition | 5th percentile | Median | 95th percentile |
|---|---|---|---|
| Coldest month, mean daily low | -14.4 °C | 1.5 °C | 13.8 °C |
| Warmest month, mean daily high | 23.6 °C | 30.6 °C | 34.6 °C |
| Annual rainfall | 862 mm | 1,259 mm | 1,665 mm |
| Rainfall in the driest quarter | 99 mm | 226 mm | 340 mm |
It is found where winters bring hard frost. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 542 research-grade observations of Hydrogalium claytonii that carry a coordinate, and this is the range those places actually span. The 5th and 95th percentiles are used rather than the minimum and maximum, because a single cultivated specimen in a heated conservatory should not widen a tropical plant's range to the Arctic.
This is not a hardiness zone. A USDA zone is the average annual extreme minimum temperature. The figure above is the mean daily minimum of the coldest month, which is a different quantity and is typically far warmer. Reading one as the other would place a plant several zones too warm, so we do not publish a hardiness zone, because we do not have one. Climate from CHELSA V2.1 (Karger et al. 2017); occurrences from 10.15468/dl.cgje2x.
Also published as 11 synonyms
A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.
- Galium claytonii Michx.
- Galium obtusum var. floridanum (Wiegand) Fernald
- Galium tinctorium L.
- Galium tinctorium subsp. floridanum (Wiegand) Puff
- Galium tinctorium subsp. tinctorium
- Galium tinctorium var. diversifolium W.Wight
- Galium tinctorium var. floridanum Wiegand
- Galium tinctorium var. submontanum W.Wight
- Galium tinctorium var. tinctorium
- Galium trifidum subsp. tinctorium (L.) H.Hara
- Galium trifidum var. tinctorium (L.) Torr. & A.Gray
Sourcesevery claim on this page
- World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
- iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
- USDA PLANTS Database. common name, checklist symbol GATI. public domain. Retrieved 2026-07-13.
- Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.
We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.