Notes on Pollen. By Lord Avebury. 509 



spherical and dry. It subsides into a hemispherical disk. That of 

 Littorella lacustris is also spherical, and subsides into a six-sided 

 hemispherical disk. 



Illecebrace^. — The pollen of Corrigiola littoralis is oval, 

 without furrows, but with three depressions, in each of which a 

 pore is situated. That of Scleranthus jyerennis is a hemisplierical, 

 six-sided disk, with two concentric circles of facets, each with a 

 depression and pore. 



Amaranthace^. — The pollen of AmaranthusiQ at first spherical, 

 subsiding into a more or less hemispherical disk, concave on the 

 flat side and rounded on the top. It is frequently deeper than a 

 hemispliere. The facets are numerous, surrounded by shallow 

 ridges, and arranged in concentric circles. The central facet gives 

 off bright red reflections, with a luminous spot in the centre. It 

 is surrounded by six hexagons, and closely resembles Lychnis. Tlie 

 pollen, seed and flowers show an affinity with the Caryophyllacese. 



CHENOPODiACEiE. — The Chenopodiacese are anemophilous. The 

 pollen is spherical, subsiding into a disk, flattened on one side, 

 with 3-4 concentric circles of facets. 



PoLYGONACEiE. — In this order the majority of species are 

 entomophilous, but many are anemophilous. The former are of 

 the usual ellipsoid type, and viscid. The stigma is capitate and 

 viscid, with small domed cells. To this type belong P. hydro- 

 inpcr, P. affine, and Rumcx pulcher. 



The anemophilous species have spherical dry pollen. The 

 stigma is more or less branclied and papillose. To this type belong 

 R. acefosa and R. acetosella. 



TiiYMELACE.-E. — The pollen of Daphne viezereicm is spherical, 

 densely and finely netted, with a gTanule or knob in the centre of 

 each mesh. 



The stigma is covered with long slender papillae. 



LoRANTHACE.E. — The pollen of the Misletoe is roundly oval, 

 echinate, with three deep furrows. 



EuPHORBiAGEJi. — In many species the pollen is ellipsoid, rounded 

 at ends and three-furrowed (E. amydaloides, Mercurialis jJcrennis, etc.). 



The Box (BiU'us) is generally anemophilous. The pollen is 

 spherical, subsiding into a 5-sided disk. 



Urticace^. — The Urticaceee are anemophilous. 



In Urtica the anthers are explosive and throw the pollen into 

 the air. The pollen is spherical, drying into a hemispherical 

 disk. 



The Elms (figs. 62-64) also have pollen in the form of a hemi- 

 spherical disk, with a central facet on the top surrounded by five 

 or six others. The pollen of the Hop and of Parietaria belongs to 

 the same type. 



MYRiCACKyE. — Myrica c/alc is anemophilous. The pollen is a dry 

 plano-convex disk with 3-4 pores and as many angles. 



