What is the difference between Beesia deltophylla and Beesia calthifolia?
In her book Gardening with Woodland Plants (Timber Press, 2007), Karan Junker says the following about Beesia:
“It is normally represented in cultivation by the species B. calthifolia. Apparently embossed veining enhances the flossy, leathery, heart-shaped leaves. Upright spikes of starry white flowers are produced from midspring into summer. Beesia deltophylla is similar.”
In American Nurseryman, vol 194, no. 12 (2001), p.66, Beesia deltophylla is described as a Dan Hinkley / Heronswood introduction grown from seed collected in Sichuan Province in 1996. “Airy, white, 1-foot racemes that appear in May through July; produces corpulent rosettes of glossy, deep-green, heart-shaped leaves up to 5 inches long.” Under the heading of how this plant differs from other species or cultivars, it simply says “durable, evergreen perennial.” It clumps but does not colonize, has a moderate growth rate and prefers light shade, and a well-drained but moist site.
Beesia deltophylla has fewer teeth and less texture, according to this article by Robbie Blackhall-Miles in The Guardian (May 1, 2014):
“A little later [after George Forrest discovered and named Beesia cordata–what we know now as B. calthifolia], Frank Kingdon Ward discovered a second species of Beesia in Burma which was named Beesia deltophylla. Very similar to B. calthifolia, this plant only has about 15 teeth on each side of its leaf as opposed to B. calthifolia’s 50, and lacks the interesting texture in its leaves. To this day, the two species are confused in cultivation.”
Here is more on B. calthifolia, from Flora of China. This site differentiates between the two species in terms of the veining on the leaves.