

MR. W. T. T. DYER ON THE GENUS HOODIA. 249 



in acetic acid ; and the flowers fell to pieces immediately the bottle 

 was disturbed. I was able, however, to carefully examine the corona, 

 and also to dissect a young bud. The "sinuses " described by Mr. 

 Bentham seemed to me without doubt to be a distinct whorl of or- 

 gans. At the reentering angle between each they are connected by 

 a kind of septum with the back of the scales forming the internal 

 series of coronal organs ; and these in their turn are adnate to the 

 base of the anthers. But these scales have a perfectly distinct 

 attachment of their own (fig. 2 5), and cannot be regarded as 

 merely inward prolongations of the angles of the external series. 

 The examination of a young bud afforded a further confirmation 

 of the existence of two whorls. The external coronal whorl forms 

 a kind of frill (fig. 2, c) which overlaps the scales of the internal 

 whorl quite distinctly above their point of attachment to it. 



Sir W. Hooker did not venture upon any analysis of the dried 

 flowers of Hoodia Gordoni collected by Burke. I have therefore 

 given a drawing of the gynostemium (fig. 1) from a plant which 

 flowered last year (1875) at Kew. The segments of the external 

 corona are very shallowly bilobed ; and the septa uniting them to 

 the internal whorl are rather more distinct than in Hoodia 



Currori. 

 In a third and hitherto undescribed species the segments of the 



external coronal whorl are deeply 2-lobed (fig. 3). The scales 



of the internal whorl have a dorsal ridge continuous with the 



septum, but with a distinct notch at the point of junction, which 



is difficult to indicate in drawing the corona as seen from 



above. 



The corona of Hoodia must therefore be regarded as " duplex." 

 As in Decabelone, the inner whorl consists of five narrow scales 

 incumbent on the anthers. In that genus, as in this, these scales 

 are attached by septa to the external whorl. In D. Barhlyi there 

 are a series of five bifid processes alternating with them, which 

 are wanting in 2). elegans. The inner coronal whorl of the former 

 appears to me to correspond to the "corona simplex" oiBoucerosia, 

 in which I regard the external coronal whorl as altogether want- 

 ing*. This may also be the case in Frerea. 



In Caralluma, which Robert Brown (followed by Decaisne 

 and Bentham) described as having a " corona simplex," it may 

 perhaps be doubted whether it is really so. Decaisne figures 



Apteranthes, which Mr. Bentham has united witiiBoucerosia, only differs from 

 i the same degree that Decabelone elegans and Barklyi differ from one another. 



