Notes on Pollen. By Lord Avehury. 505 



A few species have ellipsoid pollen with rounded ends showing 

 the three furrows, Erynyium, Astrantia, Hydrocotyle, etc. In others 

 the ends are pointed. 



ARALiACEiE. — The pollen of the Ivy {Hcdera) is broadly oval or 

 ellipsoid, rounded at the ends and finely netted. The end view is 

 triangular with the furrows in the angles. 



CoRNACE^. — The pollen of Cornus is of the common ellipsoidal 

 form with the usual three furrows on the angles. 



CAPRiFOLiACEiE. — In this order the simplest form of pollen is the 

 common ellipsoid type with three furrows and three pores. To this 

 groiip belong Adoxa, Viburnum, Sambiictcs, etc. ; the grains differing, 

 however, somewhat in different species as regards breadth and the 

 form of the ends. 



A different, or much modified type, is presented by the Honey- 

 suckle (Lonicera ). L.perichyinevm. (figs. 51, 52) has an obtusely trian- 

 gular pollen with three furrows, one on each angle. As the pollen- 

 grain dries the subsidence sometimes proceeds until the whole area 

 has sunk almost to the axis, so that it consists of three longitudinal 

 ridges M'ith the furrows at the ends. The sides sometimes curl 

 over, giving the pollen a peculiar appearance, which has led to 

 some misapprehensions. 



According to Edgeworth it is spherical. This, perhaps, refers 

 only to the first form. 



Stellat^e. — The common ellipsoid type with three furrows also 

 occurs in this order, but the most prevalent type is barrel-shaped 

 with a greater number of ridges and furrows. In some Galiums 

 (G. borcale) there are 5 ridges, but 6 are common; G. aparine and 

 some others have 8 ; Sherardia arvensis 12. The surface is generally 

 smooth, but sometimes granular, or more or less finely netted. In 

 Exostemma it is echinulate or finely spiny. 



Yalerianace.e. — The oblong form witli three furrows is pre- 

 valent in this order. The surface is granular or echinulate. 



DiPSACE.^. — The pollen is generally oval to globose, and spiny 

 or echinulate. The furrows are short and deep. In CepJialaria 

 tatarica the end view is triangular, and the furrows are on the 

 angles. 



The pollen of Marina is very peculiar. It is oblong, rounded 

 at the ends, smooth, and furnished with a remarkable outgrowth 

 at each of the three pores. This outgrowth resembles the thickened 

 mouth of a bottle, furnished with a neck of considerable length, 

 while the slightly protruded intine resembles the cork. The three 

 processes are distributed equidistantly round the equator of the 

 grain, as seen in side view. The end view is orbicular, and is so 

 much foreshortened that they appear on the periphery. The 

 pollen-tube is cylindrical or filiform, not thickened at the base, 

 and is suddenly protruded to a considerable length in water. 



CoMPOSiTyE. — The pollen in the great majority of species is 

 October 16th, 19m 2 m 



