The following notes are based on a study of herbarium specimens of neotropical Lauraceae and are the first results of a long-term project on the American representatives of that family. Unless otherwise stated, all specimens studied are deposited in the herbarium of the Missouri Botanical Garden (MO). When necessary, flowers were softened by boiling for about half an hour. Softening with detergent required much more time (usually about two hours) and this method was discontinued. Lauraceous flowers are trimerous and consist of two (usually equal) whorls of three tepals and four whorls of three stamens, which are numbered from outside to inside with Roman numerals; the anthers of whorl IV, the innermost ones, are reduced to staminodia or lacking. Aiouea lundelliana Allen, J. Arnold Arbor. 26: 419. 1945. TYPE: Panama. Chiriqui, White 225 (holotype, MO!). Allen (1945) cited one flowering collection (the type) and two fruiting collections in her description. Kostermans annotated the type in 1959 as Aiouea costaricensis (Mez) Kostermans, a species restricted to Costa Rica and Panama. However, Renner (1982) excluded the species from Aiouea and referred it to Ocotea. In Ocotea it would key to 0. tonduzii Standley, known from Costa Rica and Panama; indeed, Allen (1945) mentioned in the discussion of 0. tonduzii that fruiting material is often confused with that of Aiouea (which she called Aniba by mistake) and that differences are very hard to formulate. Aiouea lundelliana and A. costaricensis are said to differ in leaf characters: leaves to 16(-18) cm long and 7.5 cm wide with apex obtusely and shortly acuminate and reticulation slightly prominent beneath in A. lundelliana and leaves to 12(-13) cm long and 6 cm wide with obtuse or rounded apex (very occasionally shortly acuminate) and reticulation very prominent beneath in A. costaricensis. These differences are weak and it is likely that only one species of Aiouea occurs in Costa Rica and Pan-