LESSONS IN BOTANY. 213 



Ordinarily the calyx is below the ovary, but sometimes the 

 calyx adheres to the ovary, so that the stamens and petals are 

 around or above the ovary, when the ovary is said to be inferior, 

 half inferior, or superior, as the case may be. Sometimes the 

 leaf forming the pistil is not closed, the pistil being a scale-like 

 leaf bearing the ovules on its upper or inner face near the base. 

 This form of pistil is peculiar to the pine family which is named 

 gymnospermous, or naked-seeded. 



The ovule at first is a mass of parenchyma, a little later an 

 integument grows over the mass called the secundine coat, and 

 later another integument is formed called the primine coat. These 

 coats do not completely cover the ovule, a small opening called 

 the micropyle always remaining over its apex. Later an embryo 

 sac forms near the apex of the ovule. 



In fertilization, the pollen grains are conveyed to the stigma 

 by the wind, by insects, or birds, or in some other way. The 

 grain resting on the moist surface of the stigma, absorbs mois- 

 ture and germinates, sending out a tube which penetrates the 

 soft tissues of the stigma and style, to the cavity of the ovary 

 where it enters the micropyle of an ovule, and through its tissues 

 to the embryo sac, where fertilization takes place. 



As a result of the fertilization there is formed a proembryo, 

 from which is developed the embryo, which consists of one or two 

 leaves or cotyledons, the plumule and the root or radicle. 

 With the embryo in the embryo sac is formed the endosperm 

 which serves to nourish the embryo. The walls of the ovule 

 thicken and harden and the seed is formed. 



Fruit usually consists of the seeds inclosed in a variously 

 modified ovary. Sometimes the wall of the ovary thickens and 

 becoming soft as it ripens, forms such a fruit as the currant, 

 gooseberry, grape and tomato. This softened wall may be cov- 

 ered with a thick skin as in the orange and lemon, or a hard rind 

 as in the melon and squash. While in the cherry and peach the 

 inner part of the ovary forms a stony wall about the seed while 

 the outer forms the delicious fruit. The blackberry consists of 

 the softened end of the stem on which the flower stood, covered 



