386 PLANT STUDIES 



Petal : one of the floral leaves which make up the corolla. 



Photosynthesis : the process by which chloroplasts, aided by light, 

 manufacture carbohydrates from carbon dioxide and water. 



Pistil : the central organ of the flower, composed of one or more car- 

 pels. 



Pistillate : applied to flowers with carpels but no stamens. 



Pollen : the microspores of Spermatophytes. 



Pollen-tube : the tube developed from the wall of the pollen grain 

 which penetrates to the egg and conducts the male cells. 



Pollination : the transfer of pollen from anther to ovule (in Gymno- 

 sperms) or stigma (in Angiosperms). 



Polypetalous : applied to flowers whose petals are free from one an- 

 other. 



Pkothallium : the gametophyte of Perns. 



Protonema: the thallus portion of the gametophyte of Mosses. 



Receptacle: in Angiosperms that part of the stem which is more or 

 less modified to support the parts of the flower. 



Rhizoid : a hair-like process developed by the lower plants and by in- 

 dependent gametophytes to act as a holdfast or absorbing organ, 

 or both. 



Saprophyte : a plant which obtains food from the dead bodies or body 

 products of plants or animals. 



Scale : a leaf without chlorophyll, and usually reduced in size. 



Sepal: one of the floral leaves which make up the calyx. 



Sexual spore : one produced by the union of gametes. 



Sperm : the male gamete. 



Spiral : applied to an arrangement of leaves or floral parts in which 

 no two appear upon the axis at the same level ; often called alter- 

 nate. 



Sporangium : the organ within which asexual spores are produced 

 (except in Bryophytes). 



Spore : a cell set apart for reproduction. 



Sporoqonium : the leafless sporophyte of Bryophytes. 



Sporophore : a special branch bearing asexual spores. 



Sporophyll : a leaf set apart to produce sporangia. 



Sporophyte : in alternation of generations, the generation which pro- 

 duces the asexual spores. 



Stamen: the microsporophyll of Spermatophytes. 



Staminate : applied to a flower with stamens but no carpels. 



Stigma : in Angiosperms that portion of the carpel (usually of the style) 

 prepared to receive pollen. 



