Mr. Hassall on the Structure of the Pollen Granule. 549 



taken from the stigma spherical, from the imbibition of the abundant 

 secretion furnished by that organ. 



Allamanda cathartica. Vinca herbacea. 



Plumeria conspicua. V. rosea. 



Pollen grain spherical when removed from the stigma and fur- 

 nished with four pollen tubes. PI. XIV. fig. 37. 

 Nerium Oleander. 



Gentianace^. 

 Pollen grain cylindrical, three-lobed. 

 Chironia pubescens. Gentianella cruciata. Gentiana asclepiadea. 



SoLANACEiE. 



Cylindrical, three-lobed. PI. XIV. fig. 38, 39, 40, 41, 42. 



Hyoscyamus niger. Saracha viscosa. 



H. pallidus. Atropa belladonna. 



Petunia atropurpurea. Physalis oxalidifolia. 



P. violacea. P. Alkekengi. 



P. rosea. Solanum Dulcamara. 



Lycopersicum erythrocarpum. S. stramonifolium. 



Datura Stramonium. Capsicum annuum. 



Many of the granules of the two following species are four-lobed. 



Nicotiana Tabacum. Solanum tuberosum. 



SCROPHULARIACE^. 



Pollen grain cylindrical, three-lobed. See fig.43. 



Buddleia globosa. Franciscea mutabilis. 



Veronica longifolia. Schizanthus pinnatus. 



V. Chamsedrys. Rhodochiton volubile. 



Gratiola oflicinalis. Antirrhinum majus. 



Mimulus guttatus. Linaria pilosa. 



M. elatus. L. genistoides. 



M. roseus. L. purpurea. 



Digitalis purpurea, L. dalmatica. 



Russelia juncea. Scrophularia nodosa. 



Penstemon pubescens. S. aquatica. 



P. pentaphyllum. Alonsoa urticifolia. 



P. speciosum. Calceolaria elegans. 



P. difFusum. Celsia Cretica. 



Anthocercis albicans. Verbascum Phoeniceum. 



Franciscea Hopeana. V. Thapsum. 



Exception. 



Pollen granules united in fours, three upon the same plane and 

 one resting on these ; the three lower granules appear to emit but 

 two pollen tubes, the third being most probably suppressed by the 

 union of the granules, while the upper one sends off three tubes ; 

 those in the lower grains issue opposite to each other near the point 

 of juncture of the granules, while those of the upper one are given 

 off at equal distances round the circumference, alternating with the 



