An unusual kind of nectary in the oil flowers of Monttea

SÉRSIC, A. N.; COCUCCI, A. A.

FLORA

ELSEVIER GMBH

Año: 1999 vol. 194 p. 393 - 404

0367-2530

p { margin-bottom: 0.25cm; line-height: 120%; }Monttea andMelosperma form the tribe Melospermeae, an endemic group ofsubtrobical South American Scrophulariaceae. All species of Montteahave trichome elaiophores that secrete oils which are collected byfemale solitary bees of the genus Centris equipped with specialoil-collecting structures on their forelegs. The elaiophore isbasically the same in the three Monttea species, though in M..schickenclantzii and M. chilensis it is split into two areas andarranged in two shallow pouches. In addition to oils, these flowerssecrete small quantities of nectar as an alternative reward. The formand nature of the nectar gland is unusual for the familiy and rarein flowering plants. Melosperma, which provides only nectar to itspollinators, shares with Monttea the same kind of nectary. It isderived from the base of the floral tube, corresponds anatomically tothe mesenchyrnatic type, and persists after corolla abscission. Thepresence of two rewarding systems, i.e. oils and nectar, is hereconsidered in relation to the polli- nation biology. The pollinatorsof Monttea schickendannii and M. chilensis are recorded for the firsttime. The Monttea polli- nators can have, in addition to the regularforeleg oil-collecting combs, specialized tarsal pads to collect oilsfrom trichome elaio- phores. Oil collecting organs are also presenton the middle legs, though these are not used while foraging oilsfrom Monttea.