pen·ste·mon 
(p
ĕn-st
ēm
ən, p
ĕn
st
ə-m
ən)
n. Any of numerous plants of the genus Penstemon, native to North America, having opposite leaves, variously colored flowers with a usually two-lipped corolla, and capsules containing many seeds. Also called beardtongue.
[New Latin Pēnstēmōn, genus name : Greek pente, five; see penkwe in the Appendix of Indo-European roots + Greek stēmōn, thread (in reference to its four fertile stamens and single prominent staminode ); see stā- in the Appendix of Indo-European roots.]