16 safford: a new genus of annonaceae 



segments A, B, C, D (two outer segments, A, B, and two inner 

 segments, C, D) all of which fit into grooves cut into the support- 

 ing collars F, G of figure 1 and can be rotated by grasping the small 

 knobs and sliding each segment in its track, thus increasing or 

 decreasing the size of the diamond shaped aperture at (fig. 1). 

 The ring marked E can also be rotated and a triangular aperture 

 obtained if desired. These segments can be made by a good 

 mechanic without difficulty and are so simple both in construc- 

 tion and manipulation that further description is unnecessary. 

 A movable iris diafram may also be used for the same purpose, 

 but it is less effective because it does not allow the observer to 

 change the shape as well as the position of the aperture and thus 

 to obtain intense illumination without, at the same time, intro- 

 ducing false light. 



BOTANY.— Pseudannona, a new genus of Annonaceae from the 

 Mascarene Islands; together with notes on Artabotrys uncinatus 

 and its synonymy. W. E. Safford, Bureau of Plant Industry. 



Among the Annonaceae of the island of Mauritius described 

 by Lamarck in 1786 were three species referred by him to the 

 genus Annona: A. grandiflora, A. amplexicaulis, and A. uncinata.^ 

 These were afterwards figured by Dunal in his monograph of 

 the Annonaceae, the generic name assigned to them by Lamarck 

 being retained for the first two species but the last being placed 

 in the genus Unona, under the name U. uncinata. Dunal's 

 plates show at a glance that the first two plants above named, 

 which have separate carpels, each containing several seeds, can- 

 not possibly belong to the genus Annona, the fruit of which is a 

 syncarpium composed of a number of 1-seeded carpels fused 

 together in a consolidated mass; and Unona uncinata (Lamarck) 

 Dunal has been made the type of a new genus, Artabotrys, one 

 of the distinguishing characteristics of which is the peculiar hook- 

 like peduncles of the flower, which at length serve as a support 

 for the fruit. 



That Lamarck's Anona grandiflora and A. amplexicaulis do 

 not belong to the genus to which they were assigned was recog- 



1 Laml^. Encycl. Bot. 2: 126, 127. 1786. 



