QA Df, "PnJJoii rMonthl.v Microscopical 



o* un ruutlb. L Journal, I'eb. 1, l»7u. 



" Mistress of the Seas," it behoves her not to allow her prestige 

 associated with the briny element to remain simply superficial. 

 There are laurels to be reaped, only by the hand of Science, in 

 the vast abysses of the ocean, which shall add a lustre to lier 

 diadem that shall remain untarnished till time and space shall ]>o 

 no more. 



VI. — On Pollen; considered as an Aid in the Differentiation of 

 Speeies. By Charles Bailey, Esq. 



Having recently examined the pollen of several thousand species of 

 plants, I am led to think that the characters presented by these 

 grains might prove useful as a means of differentiation in allied 

 species ; my researches, however, have not been sufficiently exten- 

 sive to form any positive conclusions, but as leisure permits I hope 

 to prosecute the subject further. In the meanwhile, the following 

 notes are thrown out as indications of some of the more noticeable 

 distinctions to be di-awn from a careful comparison of these organs, 

 and they may serve to draw the attention of others to the matter. 



There are four points, in one or other of which pollen-grains of 

 plants belonging to the same genus may be found to differ from 

 each other, viz. form, markings, dimensions, and colour. 



1. Form. — It has long been noticed that certain types of poUen 

 are characteristic of the natural order to which the plants which 

 produce them belong, as, for instance, the peculiar pitted polyhedral 

 pollen of the Caryophyllacefe, the spherical spiny pollen of the 

 Malvaceae, the large triangular pollen of the Onagraceee, the pecuHar 

 pollen of the Conifers, or the elliptical pollen of the Liliacese and 

 other monocotyledonous orders ; in fact, most orders possess a type 

 sufficiently marked to be characteristic of each. This statement, 

 however, must be accepted with limitations; the Compositse, for 

 instance, have three or more well-marked types, represented by the 

 beautifully sculptured poUen of the Chicory, the miaute oval spiny 

 pollen of the Asters, Calendulas, Cacalias, &c., and another form 

 wholly destitute of spines, as in the Centaurea scahiosa. There 

 are, besides, other natural orders where similar variety occurs. 



But differences of form are met with in plants of the same 

 genus, by which the one species or the other is readily marked off 

 by its pollen ; thus the pollen-grain of Anemojie sulphurea is 

 roundish, but that of Anemone montana is elliptic; the pollen of 

 Aronicum Doronicum is much more elongate than that of A. 

 scorpioides; and w^hile the grains of Ranunculus i^liilonotis are 

 round and yellow, those of B. p)l(^l(^nifolius are elliptic, white and 

 smaller. 



