Penstemania  
   Based on Penstemon growing and the Western Algarve.
   http://www.penstemania.co.uk/

Dave's Garden PlantFiles: Genus Penstemon  
   Index page with links to all species and varieties of penstemon listed in the PlantFiles database of member-provided plant information and photos.
   http://davesgarden.com/pf/b/Scrophulariaceae/Penstemon/

Paghat's Garden: 'Bashful' Beard-tongue  
   One of a series of plant portrait pages documenting penstemons in this Pacific Northwest garden. Varieties featured are 'Bashful', 'Prairie Dusk', 'Midnight Blue', 'Ruby', 'Apple Blossom', 'Sour Grapes', and 'Garnet'.
   http://www.paghat.com/penstemonbashful.html

Kemper: Penstemon digitalis  
   Plant portrait of foxglove beardtongue with cultural information, photos, and noteworthy characteristics.
   http://www.mobot.org/gardeninghelp/plantfinder/Plant.asp?code=G590

Plant Hoe Gardening: The Glorious Penstemons  
   Home gardener presents a gallery with some information of penstemon varieties growing in the garden.
   http://home.earthlink.net/~meltoncnc/penstemon.htm

The Penstemon Website  
   Enthusiast's collection of links, information (both for gardeners and botanists), and photographs of penstemon species and varieties.
   http://www.biosci.ohio-state.edu/~awolfe/Penstemon/Penstemon.html

The Penstemons: Seed Germination Methodology  
   Two pages in Tom Clothier's extensive plant germination database dedicated exclusively to penstemon species, which are often finnicky and require a wide variety of germination conditions.
   http://tomclothier.hort.net/page08.html