92 



SEEDS. 



Fig. 120. 



OF SEEDS. 



30. The seeds, which, during the early period of 

 their development, are called ovules, are produced in 

 the interior of the cells of the carpel or ovary, along 

 the ventral suture of this organ (jig* 120). 



31. That part of the carpel from which the seeds 

 spring is named the placenta or trophosperm (from 

 the Greek, trepho, I nourish, and sperma, seed, seed- 

 nourisher), and the stalk or thread by which the 

 seeds are attached to it, we call the funicula (Latin, 

 little cord) or podosperm (from the Greek, pous, in 

 the genitive, podos, foot, and sperma, seed, seed-foot 

 or seed-stalk). 



32. The funicula in general resembles a little 

 pedicle, and its extremity is expanded sometimes 

 around the seed so as to envelope it more or less, 

 and constitute what is named the aril (arillus). 



Sometimes this expansion of the funicula is thick and fleshy ; 

 sometimes thin and membranous ; its form varies considerably. 

 In the nutmeg tree, for example, the aril forms a fleshy lamina 

 of a bright red, divided* in shreds which envelope the nutmeg, 

 and constitutes the spice called mace. It is to be remembered 

 that the aril is found only in those plants that have a monope- 

 lalous corolla. 



33. The seed itself is the part of the perfect fruit contained in 

 the interior of the carpel, and encloses the body which is destined 

 to become the new plant. The point by which it adheres to its 

 funicula, generally has the appearance of a small scar or cicatrix, 

 and is called the hilum. Finally, the seed is composed of two series 

 of organs ; namely, the accessory parts, and the essential parts. 



34. The accessory parts of the seed are 

 divided into the spermoderm (from the Greek, 

 sperma, seed, and derma, skin) or episperm 

 (from the Greek, epi t upon, and sperma, seed), 

 and the albumen ; the essential part is called the 

 embryo (jig- 121). 



35. The spermoderm or skin of the seed is 

 Fig. 121. sometimes a simple membrane, and sometimes a 



Explanation of Fig. 121. The seed of a bean, split open to show the 

 spermoderm (a), the plumule (c), and the radicle (6). 



30. Where are seeds formed ? What are ovules ? 



31. What is the placenta ? What is the funicula? 



32. What is the aril ? What is mace ? 



33. What is the hilum ? 



34. What constitutes the accessory parts of the seed ? 



35. What is the spermoderm ? 



