POLLEN. 3 



Mr. Bennett would divide the pollen into those which are 

 wind-borne, or anemophilous, and those which are not so 

 scattered, or entomophilous ; but the grains are by no means 

 all globular, as he there asserts. The Graminese and Cyperaceae 

 are usually prismatic. The Populus has globular pollen, 

 while the Salix, in the same family, is somewhat cylindric, as 

 is that of Rheum, which is probably anemophilous, and the 

 dioecious Rumices, with three slifcs. 



Plantago, which appears to be also anemophilous, varies 

 from a polyhedric to the simple form, while the wind-borne 

 pollen of the Coniferse is very different. 



The Urticse are very small and elliptic, with three slits, 

 withering into a prismatic form. 



The Grasses and Cyperacese, and perhaps the Plantaginese, 

 are without the sticky nature of the outer coat, which obtains 

 through all other pollen grains. 



Some grains throw out a quantity of tubes, by which they 

 are hung together, as in Richardia cegyptiaca, Strelitzia 

 regina, and the Rhododendron, &c., but more usually they are 

 quite distinct. I omit any account of the peculiar pollen of 

 the Asclepiadese and Orchidese, which have not common 

 loose grains of pollen, but joined together in a coherent mass. 

 I also do not intend to make any remarks as to the struc- 

 tural nature and function of the fovilla and the pollen grains. 



I have found but three or four instances in which the 

 same anther produces two or three forms of pollen ; usually 

 they are all similar, often with some small or imperfect 

 grains ; but in the Mimulus luteus I have found the simple 

 form, common in the Scrophulariacese, mixed with the coiled 

 form, which H. Mohl pointed out in the Mimulus moschatus. 

 [ have not been able to find this coiled form myself in the 

 latter, and Mr. W. Smith considers it an error of H. Mohl's ; 

 but in this he is doubtless mistaken, for I have found it in 

 the next species, M. luteus (No. 138). I have also found many 

 forms of pollen in the Browallia elata (No. 146), in the same 

 anther, but not in the coiled form ; and H. Mohl mentions 

 others also which I have not had the opportunities of 

 examining. 



I find also two forms in Thalictrum flavum and glaucum 

 (Nos. 429-432), probably also in Ranunculus auricomus, as 

 remarked by Hassall and myself in the Anisogeisos. 

 B 2 



