Both Phormium

Phormium colensoi vs Phormium tenax

These two are not on this page because a keyword tool suggested them. They are here because our own identification model genuinely mistook one for the other, on real photographs, 5 times. We publish the rate, and then we tell you what actually separates them.

Confused 5x by our model Same genus Phormium Method published

Side by sidefigs. a and b

Phormium colensoi, photographed by Tony Wills
fig. a Tony Wills, CC BY-SA 4.0

Phormium colensoi

Mountain flax
Phormium tenax, photographed by Joe Dillon
fig. b Joe Dillon, CC BY 4.0

Phormium tenax

New Zealand flax

How often our model gets it wrong measured, not estimated

When the plant was The model said How often
Phormium colensoi Phormium tenax 3 of 16 (19%)
Phormium tenax Phormium colensoi 2 of 18 (11%)

The confusion is asymmetric, which is common and usually informative: it means one of these has a character the other lacks, rather than the two simply looking alike.

Measured on 38,299 openly licensed, research-grade photographs. Full method and dataset.

What actually separates themon the record

Family Both Asphodelaceae. The family does not separate them.
Genus Both Phormium. Congeners, which is why this is hard.
Flowering Peaks in November versus November. Timing does not separate them. (n = 247 and 415.)

What we do not have yet: the diagnostic morphological character that a botanist would key on, from a source we can cite. We are not going to invent one. Until we have it, this page tells you the two are genuinely confusable, how often, and what the taxonomy and the flowering data do and do not settle.

Both recordsfull pages