Ellis–Roberts viability equation · probit maximum likelihood

How long do
these seeds have?

The workbench for building seed-longevity models — fit your germination data against every published model at once, and let goodness-of-fit pick the winner. Ellis–Roberts is the standard; when a lot breaks its assumptions, the alternatives are right here to catch it. Every number marked with its origin, never silently mixed.

Calculate — from one lot to a whole collection →Learn how it all works
Photography © Seeds of Hawaiʻi — 273 photographs, 85 taxa →
The line above is not decoration — it is the Ellis–Roberts viability equation, computed at render. Everything here is about that curve.
496
taxa in the published catalog
29,020
real germination tests behind the pipeline's validation
4
decay models fit head-to-head, ranked by AICc
7
test harnesses, all green, on every build
Three tiers · never mixed
MEASURED

Your seed lot

Paste germination-test counts and get a live probit fit — σ, Ki, and every P-threshold — computed from your data alone. Nothing pooled, nothing averaged in.

FEDERATED

The world's collections

Search longevity constants federated from Kew's Seed Information Database and the published comparative literature, each record stamped with where it came from and how it was measured.

PREDICTED

The untested species

For seeds nobody has aged yet, estimate longevity from seed mass, family, storage behaviour, and climate of origin — returned as an honest prior with an interval, never a bare guess.

The seeds themselves
All photography →
Bidens macrocarpa — seed close-up, Seeds of HawaiʻiCenchrus echinatus — seed close-up, Seeds of HawaiʻiCyanea coriacea — seed close-up, Seeds of HawaiʻiCyanea spathulata — seed close-up, Seeds of HawaiʻiCyrtandra lessoniana — seed close-up, Seeds of HawaiʻiDubautia plantaginea subsp. magnifolia — seed close-up, Seeds of HawaiʻiGahnia beecheyi — seed close-up, Seeds of HawaiʻiLachnagrostis filiformis — seed close-up, Seeds of HawaiʻiMelicope knudsenii — seed close-up, Seeds of HawaiʻiPhyllostegia helleri — seed close-up, Seeds of HawaiʻiSchiedea haleakalensis — seed close-up, Seeds of HawaiʻiTetramolopium humile subsp. humile — seed close-up, Seeds of Hawaiʻi
© Seeds of Hawaiʻi
On the bench
Guided fitOne seed lotCounts in, fitted decay curve out — every knob explained as you go.Open →Batch fitA whole collectionMany taxa and accessions in one upload, every lot fit independently.Open →RCI pipelineMonitoring dataThe full recollection-interval workflow, in your browser, with a publication sheet out.Open →Model workbenchCompeting modelsFour published decay models on the same counts, ranked by AICc.Open →
Why σ, not P50. Comparative work has moved away from P50 — it's confounded by a lot's initial viability. This bench reports σ, the probit rate of viability loss, as the primary axis, and standardises every P-threshold to each lot's own fitted Ki. P50 and P70 stay as practitioner readouts, because that's what a re-collection schedule is actually written in.