THE MORPHOLOGY OF WEEDS 



133 



as in goosefoot or lamb's quarter ; caryopsis, a grain fruit 

 in which the wall of the ovary and the testa are closely 

 united; a nut, a hard one-celled and one-seeded fruit, 

 usually produced from an ovary with two or more cells, 

 as in the hazelnut and acorn ; and the paired fruits, as the 

 cremocarp of the parsnip, each half of which is a mericarp. 

 The more important fleshy fruits are represented by the 

 drupes or stone fruit, such as the peach and plum ; the 

 pome, as the apple, the fleshy part of which is the en- 

 larged calyx; the pepo or gourd fruit, like the squash; the 

 berry, as the grape, which is fleshy. The fruit of the 

 pine is called the strobile. 



The Seed. The seed is the fertilized ovule and con- 

 sists of the following parts: The funiculus (occasionally 



lacking) or the stalk; the 

 outer and inner coats the 

 outer, frequently hard, called 

 the testa, the inner known as 

 the tegmen; the micropyle 

 or place where the pollen 

 tube enters the 

 ovule; the 

 hilum or scar 

 showing 

 where the seed 

 was attached 

 to the ovary. 

 The albumen, 



when present may be all endosperm, as in 

 the starchy part of corn, or perisperm, as in 

 canna ; this corresponds to the nucellus of 

 the ovule. Some seeds may contain both 

 endosperm and perisperm, as in the pepper. 

 Most seeds have a small quantity of peri- Cotyledons 

 sperm present. The embryo of the seed gives 

 rise to the new plant and consists of the 



B 



Fig. 82. A, germinating pea; 

 r, root; />, young stem. B, Two 

 cotyledons of pea; />, plumule; 

 c, caulicle. (C. M. King.) 



