Click thumbnails for full size, scaled to a new window.
Bruce Dunstan ... "The plant grows at the type locality epilithically on low rocks in large groups together with a green mammilaria with long brown or black thorns. On nearby bushes there is a very large form of T. atroviridipetala with small appressed scales.
|Len Colgan 01/14
||Bruce Dunstan 11/18
Habitat and range: Outside the type locality a plant was found by Alfred Lau, in Cordoba, near Angustilla in the neighbourhood of Huazamote (border between Durango and Nayarit).
The plant belongs to the complex around T. polystachia Linnaeus, and also T. mazatlanensis Rauh and T. durangensis Rauh & R. Ehlers.
Differs from T. mazatlanensis in -
• Plant saxicolous not epiphytic.
• Leaves sub-succulent, greyish white.
• Spikes wider and longer, stemmed.
• Flower bracts yellow and keeled.
• Sepals longer and sub-free.
• Petals mauve not violet.
Differs from T. durangensis in -
• Spikes longer stemmed
• Flower bracts more dense, covering the rhachis (not visible) at flowering, strongly keeled, yellow (instead of carmine red) or green, as long as the sepal or shorter.
• Sepals hard leathery, longer and sub-free."