Glossary. 419 



Pol'len (L. pollen, fine flower) : the microspores of Spermatophytes which are 



borne within the anthers, and give rise to the sperms or fertilizing cells. 

 Pol'len cells or sacs : the cavities of the anther which contain the pollen. 

 Pol'len grain : a single microspore of Spermatophytes. 

 Pol'len tube : the tubular outgrowth from the pollen grain, which penetrates 



the pistil and conducts the sperm into the ovule. Fig. 88. 

 Pol'linate : to apply pollen to the surface of the stigma. 

 PoUinif erous (L. pollen + ferre, to bear) : pollen-bearing. 

 Pollin'ium : a coherent mass of pollen, as in the milkweed. Fig. 113. 

 Polyadel'phic (Gr. polys, many; adelphos, a brother) : having the stamens 



united into several bundles or brotherhoods. 

 Polyg'amous (Gr. polys, many ; gamos, marriage) : having perfect and unisexual 



flowers on the same individual, or on different individuals of thesame species. 

 Polyg'amo-dioe'cious ; having perfect and unisexual flowers on different indi- 

 viduals of the same species. 

 Polypet'alous {Gx. polys, many; petalon, a leaf) : having several separate petals. 

 Poma'ceous (L. pomum, a fruit) : like an apple or pear; producing pomes. 

 Pome : a fruit of the apple, pear, and quince type. Fig. 333. 

 Pore : any small aperture, as in some anthers for the discharge of pollen. 

 Por'ous or porose' : pierced with small openings or pores. 

 Poste'rior: next to or toward the main axis; superior. 

 Pos'ticous (L. posticus, posterior) : situated on the outer side of a filament. 

 Praemorse' {L; prce, before; mordere, to bite) : appearing as if bitten off. 

 Prick'le : outgrowths of the epidermis or of the bark, with sharp point. 

 Prismat'ic (L. prisma, a prism) : having the form of a prism. 

 Procum'bent (L. pro, forward; cumbens, lying down) : lying on the ground. 

 Proliferous (L. proles, offspring; ferre, to bear) : producing offshoots. 

 Pros'trate : lying flat upon the ground. 

 Proteran'drous or protan'drous (Gr. proteros, first; aner, andros, a man) : 



having the anthers mature before the stigmas of the same flower are 



ready to receive the pollen. 

 Proteran'dry or protan'dry : the condition of having the anthers mature 



before the stigmas. 

 Proterog'ynous or protog'ynous {G-c. proteros, first; gyne, a woman) : having 



the stigmas ready to receive the pollen before the anthers of the same 



flower are mature. 

 Proterog'yny or protog'yny: the condition of having the stigmas mature 



before the anthers. 

 Prothal'lus or Prothallium (Gr. pro, before; thallos, a young shoot or 



sprout) : the gametophyte of ferns and other Pteridophytes, resulting 



from the germination of an asexual spore. Fig. 155. 



