Notes on Pollen. By Lord Avehury. 501 



Papaveeace^.— In this family, again, there are very consider- 

 able differences. P. somniferum, P. dtibium, Glaucium licteum, 

 Pldtystcmon calif ornicus, and Chelidonmin majus* have pollen of 

 the usual form— ellipsoid and 3-furrowed— with the ends rounded, 

 but in P. hracteolatum pointed. In P. rhvas, Glaucmm fulvum, 

 Dicentra spectaUlis, Meconopsis camhrica, and 31. nepalensis, it is 

 broader and granular. 



In P. alpinum, P. orientale, Glaucium serpieri, Meconopsis acu- 

 leata, Corydalis Iracteata (according to White), and C. lutea, it is so 

 short as to be almost, and in C. capnoides, 0. solida, 0. cava, and 

 C. cornicidata actually spherical. These pollens are almost smooth. 

 Those of Argemone mexicana, A. hispida, Corydalis glauca, Di- 

 centra formosa, are similar in form, but the surface is netted. 



Escholtzia californica has a roundly ellipsoid pollen with from 

 four to eight furrows. 



In Bocconia cordata the pollen is a plano-convex disk with few 

 facets ; in Stylophorum jap)onicum the facets are smaller and more 

 numerous ; that of Sanguinaria canadensis, according to White, is 

 a 6-sided densely granular disk. 



Bocconia microcarpa (figs. 40-42) appears to be anemophilous. 



The pollen oi Fumaria officinalis and F. parvifiora is 6-12-sided. 



The pollen of this order, and particularly of Papaver, are higlily 

 coloured ; sometimes yellow, as in Chclidonium majus ; blue, violet, 

 and purple are, however, predominant. 



Crucifee^. — I have examined a large number of species 

 belonging to the Cruciferse, and the pollen is very uniform. 

 The prevailing form is ellipsoid, more or less rounded at the 

 end, with three furrows, and the chief modifications are differ- 

 ences in size, colour, and in some species being more abrupt at the 

 end. The prevailing colour is yellow, usually light, but this is some- 

 times obscured by a brown colouring matter as in Coronopus. Most 

 of them contain numerous oil globules, reflecting a coloured light, 

 and these, together with the brown and yellow colours, serve to 

 make the grain more or less opaque. 



PiESEDACE^. — The pollen of our English Mignonettes belongs 

 to the usual ellipsoid form \vith three furrows. 



CiSTACE^. — The Rock Eose {Helianthcmum vulgarc) has pollen 

 of the usual ellipsoid form with three furrows. 



That of the species of Cistus which I have examined is more 

 nearly globular, in some species smooth, in others granular. 



ViOLACE.E. — The Violets and Pansies have two distinct forms 



of pollen. In the violets we have the common ellipsoid form with 



three furrows. The stigma is small and at the end of a bent beak. 



That of the pansies, on the contrary, is large and hollow, with 



* Edgeworth, on the contrary, describes the pollen as " globular, with 

 numerous round spots." 



