502 Transact/ions of the Society. 



a viscid lip ; the pollen is large and brick-shaped, with a furrow on 

 each of the four angles. V. tricolor has sometimes five angles and 

 is occasionally somewhat constricted in the middle. 



POLYGALACE^. — The pollen of our Milkwort is more or less 

 barrel-shaped and ribbed, sometimes, however, constricted at the 

 middle. 



The simplest type I have met with is F. ralcarea (figs. 43 and 44), 

 with 9 furrows; P.' ndgaris has 12, P. myrtifolia and P. grandi- 

 Jiora have 18, P. oppositifolia 20 bifid ridges. Fresh pollen shows 

 a beautiful play of colour — red, green, and yellow in longitudinal 

 bars and lines ; gradually, however, they fade away. 



Caryophyllace^. — The pollen falls into two groups. That of 

 Sileneae (figs. 45-46) is a plano-convex disk with more or less 

 numerous facets, generally 5-9, each with a pore in the centre. The 

 Cheddar Pink (Dia7ithus avsius) has a pentagonal or hexagonal facet 

 in the centre, with a facet for each face. The surface is in some 

 species smooth, in others granular. Of all our English species 

 LycJtnis githago has the largest pollen and also the largest seeds. 

 In some species {DiantMis sanguineus and ruhens, Silene noctifiora, 

 etc.) the ridges almost or entirely disappear. 



The pollen of the Alsineee belongs to quite a different type, 

 being of the ordinary ellipsoid form with three furrows. This is 

 additional evidence how much the Alsineaj differ from other Caryo- 

 phyllacese. 



PoRTULACE^. — The pollen is ellipsoid, but in our English species 

 at any rate so short as to be almost spherical. 



Tamaricace/E. — The pollen is of the common ellipsoid type. 



ELATiNACEiE. — According to White's drawings the same applies 

 to this order. 



Hypericace.^*:. — The pollen in our English species is of the 

 usual ellipsoid type with three furrows. 



Malvace.,^. — The pollen is generally large, spherical, and spiny. 

 The spines are of two sizes. In some foreign species the spines are 

 very short and almost rudimentary. The pores are numerous. 



TiLiACEiE. — The pollen of the Lime is peculiar. It is a thin 

 annular disk with three notches on the margin. One face has a 

 tripodial ridge, the limbs of the tripod reaching the margin at the 

 notches ; the other side has a corresponding depression. 



This form of pollen appears to be an extreme modification of 

 the ellipsoid pollen which appears in its common form in other 

 species of the Order, as for instance in Sparmannia. 



LiNACEiE. — The pollen of Linum is a modification of the common 

 elliptic type, being in some species so short as to be almost 

 spherical. 



Geraniace^:. — This order presents several types of pollen. 

 That of Geranium is spherical or nearly so, with three furrows and 

 pores, and granules sometimes developed into short, blunt, spines. 



