Lachenalia cernua, Assegaaiboskloof, contour track s of Berg River lower valley

Lachenalia cernua G.D.Duncan

Rocket Viooltjie

Climate known 29 photographs Bulb, tuber or caudex

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 · Lachenalia

Lachenalia is a genus of bulbous perennial plants in the family Asparagaceae, subfamily Scilloideae, which are usually found in Namibia and South Africa. Most of them have a dormancy period, but new roots will always grow every year.

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

Family

Asparagaceae

Described by

G.D.Duncan

Native to

Cape Provinces

Wild records

39 in range· 13 open

At a glance

Warmest month

27°C

Feb, mean day; nights 15 °C (CHELSA)

Rain

1306mm/yr

12 wet months · peak Jul 223 mm (CHELSA)

Light

16–53DLI

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

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

Grouped as a bulb, tuber or caudex by the genus Lachenalia, which is reliably one kind of plant (archetype table). Rain rule: a winter growing season, October to March in the northern hemisphere (April to September at the habitat, southern). Habitat rain 1306 mm a year, wettest July at 223 mm, driest February at 30 mm (habitat calendar, southern hemisphere). Open sky over the habitat: 16 to 53 mol/m²/day. Cold floor 2.2 °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.

Cultivation

Grouped as a bulb, tuber or caudex by the genus Lachenalia, which is reliably one kind of plant (archetype table). The table holds no figure for this group, which spans too much for one minimum; the cold floor is the habitat's alone, and no prose comes from the table.

Its year Rain rule: a winter growing season, October to March in the northern hemisphere (April to September at the habitat, southern).

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

The rain rule reads a winter growing season: 70% of the year's rain (998 mm of 1306 mm) falls in April to September, cooler than the year (wet-season mean 11.7 °C against a yearly mean of 14.9 °C). Months are the habitat's, southern hemisphere; shifted six months for a northern-hemisphere collection: October to March.

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 1306 mm a year, wettest July at 223 mm, driest February at 30 mm (habitat calendar, southern hemisphere).

This species’ habitat figures, with their source.

1306 mm a year at the habitat, 998 mm of it April to September. Wettest month July at 223 mm, driest February at 30 mm. Across the envelope cells the year's total runs 586 mm to 1970 mm (10th to 90th percentile of each cell's own year) (median year across the envelope cells, CHELSA; habitat calendar, southern 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 53 mol/m²/day.

This species’ habitat figures, with their source.

Open sky over the habitat: 16 to 53 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 15, the highest 90th-percentile month 53).

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 2.2 °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 2.2 °C, the absolute minimum -0.2 °C, 4 frost nights in 44 years (NASA POWER daily minima). Warmest: the 99th-percentile day is 39.7 °C. Monthly means: coldest night 5.4 °C in July (across the envelope cells 3.1 °C to 6.8 °C), warmest day 27.3 °C in February (median year across the envelope cells, CHELSA). Cold floor: 2.2 °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: 54 to 60% 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 17 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	27 / 24–30	27 / 25–30	26 / 23–28	22 / 19–24	18 / 16–20	15 / 13–17	14 / 13–16	15 / 13–17	17 / 15–19	20 / 17–23	22 / 20–26	25 / 22–28
Night °C	14 / 12–16	15 / 13–17	14 / 12–16	12 / 9–13	9 / 7–11	6 / 4–8	5 / 3–7	6 / 4–7	7 / 5–9	9 / 7–11	11 / 9–13	13 / 11–15
Rain mm	40 / 19–64	30 / 13–47	45 / 21–68	94 / 44–142	167 / 72–252	217 / 96–318	223 / 105–316	171 / 77–262	126 / 58–194	79 / 34–133	63 / 27–103	51 / 20–83
DLI	53 / 51–53	47 / 45–48	38 / 36–40	27 / 26–29	19 / 18–21	16 / 15–17	18 / 16–19	23 / 21–24	31 / 29–32	40 / 39–41	49 / 47–49	52 / 50–53
RH %	54 / 53–58	54 / 53–59	55 / 53–59	55 / 54–59	57 / 56–60	59 / 57–60	58 / 57–60	60 / 58–61	59 / 58–62	57 / 55–60	55 / 54–59	55 / 53–59

Each figure is the median across the 17 grid cells holding the 39 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 2470:3983 (-33.525, 19.175). Over 44 years there: absolute minimum -0.2 °C, 1st-percentile night 2.2 °C, 99th-percentile day 39.7 °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 17 distinct grid cells holding the 39 in-range records; extremes and elevation at the typical cell 2470:3983 (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 -33.50_19.375, lapse-corrected -336 m at 6.5 °C/km. Elevation: ETOPO 2022, 386 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.

NativeCape Provinces

Kew's description“bulbous geophyte” · “subtropical”· quoted from WCVP, RBG Kew (CC BY 4.0); not derived here

Map marker-33.758, 19.181 · in the densest population, 39 records (100% of those in range)

Evidence usedThe map marker and the climate envelope rest on all 39 georeferenced records inside the native range; the map shows only the 13 openly licensed ones, which alone would put the marker 20 km away.

The map markerthe map marker: the openly licensed record nearest the middle of the densest 1° population of the 39 in-range records; it decides nothing.

Photographs

Photographs: (c) Tony Rebelo, some rights reserved (CC BY-SA) (2); (c) Paul Emms, some rights reserved (CC BY-SA) (5); (c) Dave U, some rights reserved (CC BY-SA).

Photographs: iNaturalist 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 Lachenalia cernua, most cited first, from OpenAlex (CC0). A mention, not a cultivation source: nothing on this page is drawn from them.

Occurrence Download