EPOW - Ecology Picture of the Week

Oily Pectis of San Cristobal

Oily Pectis (Pectis tenuifolia), Family Asteraceae (or Compositae)
San Cristobal Island, Galapagos Islands, Ecuador

Explanation:  Here we are on San Cristobal Island in the eastern corner of the Galapagos Islands of Ecuador, just below the equator.

This is an endemic species of the Galapagos, found nowhere else in the world.  Oily pectis grows as a low perennial, tap-rooted herb with strikingly colorful leaves of red, green, and a tinge of purple, and flowers with five yellow petals that are orange underneath.  

What makes this pectis "oily" are the oil glands on the underside of the leaves.  Perhaps the oil serves the purpose of thwarting any insect trying to climb the stem to feed on the flower parts, but this is only my speculation.  I could find no study of this particular species, although studies of other Pectis species (P. apodocephala and P. oligocephalo) have shown that their oils serve as natural pesticides that kill nematodes and larvae of the yellow fever mosquito.  The oil produced by Pectis papposa of the American Southwest and northern Mexico has a potent fragrance that can be used in savoring food and drinks.  And the oil produced by Pectis brevipedunculata in Brazil can serve as a vasorelaxant and muscle relaxant.  

Back in the Galapagos, Pectis tenuifolia often grows on bare rock, including lava.  For such a hardy plant, it may have some amazing uses perhaps not yet recognized!

  
Information:
     Albuquerque, M.R., S.M. Costa, P.N. Bandeira, G.M. Santiago, N. Andrade-Neto, E.R. Silveira, and O.D. Pessoa.  2007.  Nematicidal and larvicidal activities of the essential oils from aerial parts of Pectis oligocephala and Pectis apodocephala Baker.  Anais da Academia Brasileira de Ciências 79(2):209-213.
     Bradley, C.E., and A.J. Haagen-Smit.  1949.  The essential oil of Pectis papposa.  Economic Botany 3(4):407-412.
     Pereira, S.L., A.M. Marques, R.T. Sudo, M.A. Kaplan, and G. Zapata-Sudo.  2013.  Vasodilator activity of the essential oil from aerial parts of Pectis brevipedunculata and its main constituent citral in rat aorta.  Molecules 18(3):3072-3085.