508 Transactions of the Society. 



are short and deepest in the central portion of the grain, shallower 

 or even absent at the ends. According to Edgeworth the pollen of 

 Borago orientalis is oval, smooth, and not constricted in the middle. 

 SoLANACE^. — Here again the most common type is the ordinary 

 ellipsoid with three furrows (aS'. dulcamara, S. nigrum, Atropa bella- 

 donna, Hyoscyccmus niger). 



Spherical pollen occurs in K. orientalis and some other foreign 

 species. 



Fhysalis has the pollen in tetrads. That of Datura sanguinea 

 and of Mandragora ojficinarum, is spiny. 



ScROPHLfLAEiACEvE.- — Here also the ellipsoid and three-furrowed 

 type is by far the most common. 



There are, however, some variations. Verhascicm. pyramidale 

 has an oblong pollen, rounded at the ends ; Calceolaria Pavonii 

 has the ends truncate ; the side view of Mimulus glutinosus is oval. 



Euphrasia officinalis has ellipsoid pollen, but the angles 

 between the furrows are so prolonged as to give the pollen a 

 deeply trilobulate appearanre, with wide and shallow furrows. 



In Rhinanthus Cristagalli, Bartsia odo7ititcs, and Melampyrum 

 pratense, on the contrary, the dorsal aspect is so flattened that the 

 furrows are upon the angles. 



Orobranchace^. — Again the ellipsoid form with three furrows 

 is prevalent. That of Orohranche hederm is a plano-convex disk 

 with facets, which, however, are not well marked. 



LENTIBULARIACEJ3. — The pollen of Pingtdcula vidgaris in side 

 view varies from roundly oval to nearly orbicular, with 4-5 ridges. 

 The end view is orbicular with 8 shallow furrows and as many 

 broad ridges. That of P. caudata is compressed at the ends. 



In Utricidaria vidgaris it is barrel-shaped, with about 20 ridges. 

 In U. montana it is a hemispherical disk. 



VerbenacE/E. — The pollen of Verhena officinalis is oblong in 

 side view and triangular in end view, with the furrows on the 

 angles, while V. hastata has them on the sides. In V. venosa it is 

 a disk with 3-5 faces. 



The pollen of Clerodendron umbellatum is oval and spiny. 



Labiat^e. — The pollen differs very much in different species. . 



The simplest form occurs in Stachys hetonica, Leonurus cardiaca, 

 Teucrium chania^drys and T. Scorodonia. It is oblong-ellipsoid, 

 rounded at the ends, with three furrows. 



The pollen of Lamium and Ajuga is very similar. 



That of Prunella is also ellipsoid in side view, with the end 

 orbicular, and with six furrows. 



In Calamintha acinos (figs. 59-61) and Thymus serpylhim, Salvia 

 pratensis, Lycopus europma, Mentha, and Ncpcta, the pollen is 

 flattened, with six ridges. 



The surface in more or less granular, and in some cases netted. 



Plantagine^. — Plantago is anemophilous. The pollen is 



