Chamaerops humilis microcarpa, grown from seed collected by Sergio Quercellini. This "small fruit" version of Chamaerops humilis grows well in the Raleigh region, whilst other green forms of Chamaerops humilis fail - as reported by Tony Avent, the proprietor of Juniper Level Botanic Garden.

Agave gentryi x americana protamericana, hybrid created at Juniper Level Botanic Garden, where this seedling resides.

Here is a wild/natural example: https://www.inaturalist.org/observations/242823590

Agave victoriae-reginae x pseudosalmiana 'Upstanding', produced (and resides at) at Juniper Level Botanic Garden

This seedling has the longest leaves of the siblings, and has the most salmiana-like form (open rosette with recurved leaves).