The HPT-numbers mentioned here are no field numbers of collected plants. They are internal numbers (acczession numbers, receipt numbers) of the cactus collection of  Hans-Peter Thomas which are used for identification of individual plant clones in our collections. This is important since Opuntioids normally are propagated vegetatively.
Where a site locality of the respective plant is known or where a locality can be followed, this is mentioned after the plant name and the HPT-number. Otherwise the plant is mentioned as a ‚cultivation clone‘.

sulphurea, HPT 0325; Argentina