74 



species is new or not. This however seems to have been 

 hitherto omitted by systematists. It is a fine, noble-looking 

 shrub, with leaves a foot long and nine inches broad, and 

 clusters of large handsome pure white flowers. It was re- 

 ceived from Mexico by George Barker, Esq. who presented 

 it to the Horticultural Society, in whose garden it is kept in 

 the stove. 



STARCH ON THE OUTSIDE OF POLLEN-GRAINS. 

 In the Annals of Natural History, vol. iii. p. 127, there 

 is a report of a memoir upon pollen, read before the Botanical 

 Society of Edinburgh, by M. Giraud, in which memoir the 

 author states that there are "minute opaque bodies on the 

 surface of the pollen of Polemonium cceruleum, which, when 

 immersed in water, appear to be possessed of spontaneous 

 motion." Having lately been led to examine the structure 

 of pollen, I took the opportunity of enquiring into the nature 

 of that to which M. Giraud ascribes so singular a property. 

 I had no difficulty in finding the bodies spoken of, for they 

 are from ^^ to ^ooo of ^.n inch in diameter, thickly stud the 

 surface of the pollen-grain, which is itself about ^55 of an inch 

 in diameter, and are readily detached if the grains are 

 placed in water, when they float about, turning upon their 

 longer axis, with the same kind of motion as is seen in the 

 molecules contained in the interior of the pollen. They vary 

 in form from oblong to spheroidal, but I do not find them 

 opaque ; on the contrary they are transparent, like grains of 

 fsecula, and so much like them, in certain states, that I felt 

 persuaded from the first moment of seeing them that they 

 were really of that nature. The application of iodine imme- 

 diately gave them a pale blue colour ; so that if this agent 

 is in all cases a test of starch, the bodies seen by M. Giraud 

 must be of that nature. I regard this as a circumstance of 

 some physiological interest, for I am not aware that amyla- 

 ceous granules have been before detected on the outside of 

 any vegetable organ. Pollen, indeed, being developed in 

 the interior of the anther, and produced as it would seem 

 by a disintegration of the parenchyma forming the mass 

 of that organ, cannot strictly be compared to any part of a 

 plant except to the individual cells or tubes constituting the 

 elementary tissue ; nevertheless it is equally novel to find 

 fsecula secreted in the intercellular passages, its situation 



