THE SEED. 



19 



FIG. 34. 



THE SEED. 



101. The seed is the fertilized and developed ovule, and the following 

 terms used here for convenience as descriptive of the parts, the kinds 

 and the positions of the ovule are also applicable to the seed, excepting, 

 perhaps, a few changes which will be mentioned later. 



102. An ovule consists of one or two coats or integu- 

 ments: an outer coat, the primine, an inner coat, the 

 secundine, and an interior part or contents, the nucleus. 

 At a point which marks the apex of the ovule is a minute 

 hole the orifice or foramen through the integuments, 

 and at the opposite extremity the coats are blended 

 together and with the base of the nucleus; this is called 

 the chalaza. The stalklet, if there be any, supporting 

 the ovule is the funiculus, and the place of its attach- 

 ment with the ovule, the place where it breaks away when 

 a seed, is called the hilum or scar. 



103. As an ovule develops, if its axis (an imaginary 

 line passing through its center from base to apex) remains 

 straight, in the direction of the original line of growth, 

 it is said to be an orthotropous or straight ovule. More 



commonly, however, the ovule turns more or less over 

 upon the supporting stalklet, which becomes adherent 

 to its surface, and that part, extending from hilum to 

 chalaza, is called the rhaphe. It is found with the next 

 two kinds of ovules. When the ovule is turned about 

 half over, its axis being at right angles to the original 

 line of growth, it is 

 called an amphitropous 

 or half-inverted ovule. 

 When it is turned com- 

 pletely over, the axis 

 being parallel to the 

 original line of growth 

 and in the opposite 

 direction, it is said to 

 be an anatropous or 

 inverted ovule. 



104. In the preceding cases the axis of 

 the ovule remains straight, the flexion 

 taking place in the supporting stalklet; 

 but there is a form of ovule where the axis 

 itself becomes curved, the apex and orifice 

 being thus brought over near to the base 



and chalaza. Such an one is called a campylotropous or curved ovule, 

 and, as with the orthotropous ovule, has no rhaphe. 



105. The position or direction of the ovule in the cell is designated by 

 the following terms: horizontal, when growing from the side of the cell 



Fig. 34. Staminate Flowers of the Oak, enlarged. (From Hough's Elements of Forestry.) 

 Fig. 35. Pistillate Flowers of the Willow. (From Hough's Elements of Forestry.) 

 Fig. 36. Fruit of the Maple (A pseudo-platanus) a double samara. (From Hough's Ele- 

 ments of Forestry.) 



FIG. 35. 



FIG. 36. 



