Lophophora williamsii var. decipiens was described by Croizat in 1944 (Desert Pl. Life 16: 44); the name rested on a figure of a plant of unknown origin (Britton & Rose 1922, Pl. 10 fig.
Taxonomy & identification
Lophophora williamsii var. decipiens was described by Croizat in 1944 (Desert Pl. Life 16: 44); the name rested on a figure of a plant of unknown origin (Britton & Rose 1922, Pl. 10 fig. 4) matched to a single cultivated plant Croizat held. [Hansen 2000 — Lophophora fricii & williamsii var. decipiens]
The article concludes that var. decipiens cannot be upheld as a valid taxon, agreeing with earlier authors (Anderson 1980, Grym 1997); the overwhelming majority of plants labeled L. williamsii var. decipiens are in fact L. fricii. [Hansen 2000 — Lophophora fricii & williamsii var. decipiens]
Croizat's original description was limited: small-remaining plants with a pink flower having a somewhat longer tube, weakly developed ribs, and a more tubercled (gefelderte) arrangement of the warts. [Hansen 2000 — Lophophora fricii & williamsii var. decipiens]
SEM images of plants labeled L. williamsii var. decipiens show the same cone-shaped testa cells typical of L. fricii, strongly supporting that the majority of decipiens plants are L. fricii (Hansen 1996, 1998). [Hansen 2000 — Lophophora fricii & williamsii var. decipiens]
History
Because var. decipiens was described 30 years before L. fricii, most plants whose appearance clearly differed from L. williamsii and L. diffusa were historically filed under the name L. williamsii var. decipiens; in older collections L. fricii is predominantly found under the name 'decipiens'. [Hansen 2000 — Lophophora fricii & williamsii var. decipiens]
A drawing from Britton & Rose (1922) (reproduced as Abb. 20) is said to correspond in appearance to Croizat's described plant; comparison with other figured plants suggests small, offsetting plants with a pink flower and somewhat longer tube and indistinct ribs. [Hansen 2000 — Lophophora fricii & williamsii var. decipiens]