no rights reserved · observed growing wild · 2014-05-17

Cephalanthus tetrandrus (Roxb.) Ridsdale & Bakh.f.

Rubiaceae

Climate known 18 photographs

Every figure on this page is derived from public data by a stated rule and says its source; nothing here is written by a person or a model, except the Wikipedia passage, which is quoted and marked as such. How it is made.

About the genus · Cephalanthus

Cephalanthus is a genus of flowering plants in the family Rubiaceae. There are five extant species that are commonly known as buttonbush.

Text from Wikipedia, “Cephalanthus”, CC BY-SA 4.0, quoted as written.

Family

Rubiaceae

Described by

(Roxb.) Ridsdale & Bakh.f.

Native to

China South-Central, Hainan, China Southeast +9

Wild records

183 in range· 62 open

At a glance

Warmest month

31°C

Jul, mean day; nights 25 °C (CHELSA)

Rain

1821mm/yr

12 wet months · peak Jun 293 mm (CHELSA)

Light

16–34DLI

mol/m²/day, winter to summer, open sky (CHELSA shortwave)

In short condensed by rule from the cultivation cards · not written by a person

Rain rule: a summer growing season, March to August in the northern hemisphere (March to August at the habitat, northern). Habitat rain 1821 mm a year, wettest June at 293 mm, driest December at 41 mm (habitat calendar, northern hemisphere). Open sky over the habitat: 16 to 34 mol/m²/day. Cold floor -2.0 °C (1st-percentile habitat night, NASA POWER).

Each sentence is one card's own one-line form, written by the same rule as the card (Its year, Rain, Light, Temperature); the note cannot say what a card does not. Months are given for the northern hemisphere (set your site in Settings to change this), and the habitat's own alongside. The cards · the figures.

Also known as Cephalanthus glabrifolius Hayata; Cephalanthus monas Lour.; Cephalanthus monas Lour. ex B.A.Gomes; Cephalanthus naucleoides DC.; Cephalanthus occidentalis Lour. and 6 more.

Cultivation

Its year Rain rule: a summer growing season, March to August in the northern hemisphere (March to August at the habitat, northern).

This species’ habitat figures, and what two fixed rules read from them.

The rain rule reads a summer growing season: 70% of the year's rain (1339 mm of 1821 mm) falls in March to August, warmer than the year (wet-season mean 24.1 °C against a yearly mean of 20.4 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: September to February.

Read from the median year of CHELSA monthly rainfall and mean temperature across the envelope cells: the rain rule takes the smallest set of months carrying 70% of the rain and calls it winter when its mean is more than half a degree below the year's, summer when more than that above, and neither in between; the temperature rule, used only under 120 mm, names the cooler six months when they are at least a degree cooler than the other six. Months are shifted for the other hemisphere only where the temperature curve gives a season to reverse. A reading of the curves, not an observation of the plant.

Rain Habitat rain 1821 mm a year, wettest June at 293 mm, driest December at 41 mm (habitat calendar, northern hemisphere).

This species’ habitat figures, with their source.

1821 mm a year at the habitat, 1339 mm of it March to August. Wettest month June at 293 mm, driest December at 41 mm. Across the envelope cells the year's total runs 1422 mm to 3528 mm (10th to 90th percentile of each cell's own year) (median year across the envelope cells, CHELSA; habitat calendar, northern hemisphere).

CHELSA monthly precipitation, median year across the envelope cells. The rain that falls where the species is recorded; nothing about how the plant takes water.

Light Open sky over the habitat: 16 to 34 mol/m²/day.

This species’ habitat figures, with their source.

Open sky over the habitat: 16 to 34 mol/m²/day across the year (daily light integral, median year across the envelope cells, CHELSA; the lowest 10th-percentile month across the cells is 14, the highest 90th-percentile month 37).

CHELSA shortwave radiation at each envelope cell, a daily-mean flux taken to a daily total and converted at 2.07 mol of PAR per MJ. The sky over the habitat, measured; what reaches a plant under a rock, a shrub or a shade cloth is not.

Warmth and air Cold floor -2.0 °C (1st-percentile habitat night, NASA POWER).

This species’ habitat figures, with their source.

Temperature

Coldest: the 1st-percentile night over 44 years at the typical cell is -2.0 °C, the absolute minimum -10.2 °C, about 12 frost nights a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 33.4 °C. Monthly means: coldest night 5.7 °C in January (across the envelope cells 2.4 °C to 12.6 °C), warmest day 31.2 °C in July (median year across the envelope cells, CHELSA). Cold floor: -2.0 °C, which is the 1st-percentile night over 44 years at the typical cell (NASA POWER).

NASA POWER daily minima and maxima 1981–2024 at the typical cell, lapse-corrected to its elevation; CHELSA monthly means, median year across the envelope cells, CHELSA. The cold floor is the figure named in its sentence. Not a measured survival limit for any plant in a pot.

Humidity

Relative humidity at the habitat: 59 to 66% across the year (monthly means, median year across the envelope cells, CHELSA). A figure about the air, saying nothing about how the plant takes water.

CHELSA relative humidity, median year across the envelope cells.

The figures the cards read from are in Climate below, and where they came from in Natural habitat.

Climate across the habitat

day night rain 10th–90th percentile across 133 habitat cells cold quarter: the three months around the coldest night extremes over 44 years at the typical cell, marked at the edge: undated DLI, mol/m²/dayRH %each on its own scale

Figures by month

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Day °C	14 / 10–19	16 / 12–20	19 / 16–23	23 / 22–27	27 / 25–29	29 / 27–31	31 / 28–33	31 / 28–33	29 / 26–30	25 / 23–28	21 / 18–24	16 / 13–20
Night °C	6 / 2–13	8 / 5–14	11 / 8–16	16 / 14–20	20 / 18–23	23 / 21–25	25 / 22–26	25 / 22–25	22 / 20–24	17 / 15–21	12 / 9–18	7 / 4–14
Rain mm	69 / 26–164	107 / 30–226	170 / 52–226	213 / 98–255	260 / 177–351	293 / 215–407	211 / 144–327	192 / 137–323	128 / 83–521	76 / 42–413	61 / 41–301	41 / 22–189
DLI	16 / 14–20	17 / 15–20	20 / 17–25	24 / 21–29	28 / 25–31	29 / 27–33	34 / 31–37	32 / 30–35	29 / 27–30	25 / 22–28	21 / 17–24	18 / 15–21
RH %	61 / 59–66	63 / 61–67	64 / 62–67	65 / 62–68	65 / 62–68	66 / 63–69	65 / 60–69	65 / 61–68	63 / 60–67	60 / 58–66	60 / 57–64	59 / 57–63

Each figure is the median across the 133 grid cells holding the 179 in-range records, with the 10th–90th percentile span across those cells after the slash where it differs. Extremes and elevation were read at the typical cell 1303:5809 (24.825, 110.475). Over 44 years there: absolute minimum -10.2 °C, 1st-percentile night -2.0 °C, 99th-percentile day 33.4 °C. Normals: CHELSA V2.1 1981–2010 climatology, 0.05° cells (each the mean of ~36 1 km pixels). Envelope: median and 10th–90th percentile of each month across the 133 distinct grid cells holding the 179 in-range records; extremes and elevation at the typical cell 1303:5809 (its coldest month's mean night nearest the median across cells); its position is the cell centre. Extremes: NASA POWER (MERRA-2) daily 1981–2024, cell 25.00_110.625, lapse-corrected -171 m at 6.5 °C/km. Elevation: ETOPO 2022, 245 m (cell mean).

Natural habitat

Native range as published by WCVP; the marker is where the records are densest and decides nothing: the climate was read across every in-range record's cell, not at the marker.

Openly licensed records inside the range, framed on where they fall.

NativeChina South-Central, Hainan, China Southeast, Taiwan, Assam, Bangladesh, East Himalaya, Nepal, Laos, Myanmar, Thailand, Vietnam

Kew's description“shrub or tree” · “wet tropical”· quoted from WCVP, RBG Kew (CC BY 4.0); not derived here

Map marker24.7, 121.8 · in the densest population, 133 records (73% of those in range)

Evidence usedThe map marker and the climate envelope rest on all 183 georeferenced records inside the native range; the map shows only the 62 openly licensed ones, which alone would put the marker 788 km away. 1 record outside the range (gardens, roadsides, misidentifications) ignored. 4 in-range records are placed to worse than 10 km and stay on the map but off the climate.

The map markerthe map marker: the openly licensed record nearest the middle of the densest 1° population inside the densest 4° block of the 183 in-range records; it decides nothing.

Photographs

Photographs: no rights reserved · CC0 (8).

Photographs: iNaturalist and Wikimedia Commons did not answer when this page was built; what is shown came from the sources that did.

Papers naming this species

Works whose title or abstract names Cephalanthus tetrandrus, most cited first, from OpenAlex (CC0). A mention, not a cultivation source: nothing on this page is drawn from them.

Effects of Multi-Growth Periods UAV Images on Classifying Karst Wetland Vegetation Communities Using Object-Based Optimization Stacking Algorithm

Ya Zhang, Bolin Fu, Xidong Sun, Hang Yao (2023) · Remote Sensing

Rapid Identification of Constituents in Cephalanthus tetrandrus (Roxb.) Ridsd. et Badh. F. Using UHPLC-Q-Exactive Orbitrap Mass Spectrometry

Sunv Tang, Jianbo Yang, E Shuai, Shuo He (2022) · Molecules

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