Cynoglossum zeylanicum (Ceylon hound's tongue)

Plate 1 figs. a–h · 8 separate observations

Cynoglossum zeylanicum, photographed by Manis Lin — fig. a Manis Lin, CC0 1.0 / 2022-01-23 / obs. 177021583

Cynoglossum zeylanicum, photographed by Dinesh Valke — fig. b Dinesh Valke, CC BY-SA 4.0 / obs. 160117584

Cynoglossum zeylanicum, photographed by Jacy Chen — fig. c Jacy Chen, CC BY 4.0 / obs. 130015570

Cynoglossum zeylanicum, photographed by Lin Scott — fig. d Lin Scott, CC BY 4.0 / obs. 42106016

Cynoglossum zeylanicum, photographed by Tatsutomo Chin — fig. e Tatsutomo Chin, CC BY 4.0 / obs. 41043497

Cynoglossum zeylanicum, photographed by Cheng-Tao Lin — fig. f Cheng-Tao Lin, CC BY 4.0 / obs. 11910134

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 23 botanical countries

Native distribution of Cynoglossum zeylanicum, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows. Regions too small to draw at this scale are marked with a dot.

Region	TDWG code	Continent
Assam	ASS	ASIA-TROPICAL
Bangladesh	BAN
East Himalaya	EHM
India	IND
Jawa	JAW
Malaya	MLY
Myanmar	MYA
Nepal	NEP
Pakistan	PAK
Philippines	PHI
Sri Lanka	SRL
Thailand	THA
Vietnam	VIE
West Himalaya	WHM
Afghanistan	AFG	ASIA-TEMPERATE
China North-Central	CHN
China South-Central	CHC
China Southeast	CHS
Hainan	CHH
Japan	JAP
Korea	KOR
Taiwan	TAI
Tibet	CHT

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 154 in flower of 214 examined

50%

17%

25%

14%

62%

88%

89%

76%

81%

73%

67%

Proportion of examined Cynoglossum zeylanicum in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	3	6	50%	19% to 81%
Feb	1	6	17%	3% to 56%
Mar	2	8	25%	7% to 59%
Apr	2	14	14%	4% to 40%
May	8	13	62%	36% to 82%
Jun	28	32	88%	72% to 95%
Jul	56	63	89%	79% to 95%
Aug	22	29	76%	58% to 88%
Sep	13	16	81%	57% to 93%
Oct	11	15	73%	48% to 89%
Nov	4	6	67%	30% to 90%
Dec	4	6	67%	30% to 90%

Peak flowering in Jul. Each bar is the share of Cynoglossum zeylanicum 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. 154 of 214 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 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 524 observations

Condition	5th percentile	Median	95th percentile
Coldest month, mean daily low	-0.7 °C	2.7 °C	9.9 °C
Warmest month, mean daily high	16.5 °C	20.7 °C	29.1 °C
Annual rainfall	2,717 mm	3,677 mm	4,876 mm
Rainfall in the driest quarter	151 mm	260 mm	603 mm

It is found where winters bring light 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 524 research-grade observations of Cynoglossum zeylanicum 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 20 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.

Anchusa zeylanica Vahl ex Hornem.
Anchusa zeylanica Vahl ex Hornem.
Cynoglossum coeruleum Buch.-Ham. ex D.Don
Cynoglossum denticulatum var. zeylanicum (Sw. ex Lehm.) C.B.Clarke
Cynoglossum edgeworthii A.DC.
Cynoglossum furcatum Wall.
Cynoglossum furcatum f. albiflorum (H.Hara) Yonek.
Cynoglossum furcatum var. lanceolatum C.B.Clarke
Cynoglossum furcatum var. villosulum (Nakai) Riedl
Cynoglossum furcatus Wall.
Cynoglossum heynei G.Don
Cynoglossum imeretinum Kusn.
Cynoglossum ovatum Moon
Cynoglossum villosulum Nakai
Cynoglossum zeylanicum Thunb. ex Lehm.
Cynoglossum zeylanicum f. albiflorum H.Hara
Echinospermum zeylanicum (Sw. ex Lehm.) Lehm.
Myosotis zeylanica Sw. ex Lehm.
Paracynoglossum imeretinum (Kusn.) Popov
Rochelia zeylanica Roem. & Schult.

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 CYFU8. 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.