GERMINATION OF SEEDS. 55 



The membranes of the seed, as stated, are three, the outer one forms 

 the tube of the flower cup, the middle the fleshy part of fruit, as of 

 the apple, peach and melon, and the inner with three partitions, en- 

 closes the seed, forming, as in the cherry and filbert, one chamber and 

 in the apple and pea two. The first is thick and stony, and the second 

 thin and husky. 



Germination is the evolution of a young plant from the seed. Some 

 seeds, as the coffee, require to be sown on being gathered ; others, 

 preserved from heat, moisture and frost, may be long kept. Soil is 

 riot indispensable to germination, as mustard germinates on a sponge 

 or moist flannel, and some seeds in water, on glass, bark rocks, etc. 

 Water is indispensable, but too much macerates the seed and it rots, 

 as with the grains, beans etc., in wet seasons. 



Mr is also essential, as the seed must receive oxygen from it. A 

 seed will not germinate under a receiver exhausted of air ; when 

 buried too deep in the soil they receive no air and will not vegetate. 

 Acorns that have lain for centuries, on being ploughed up, have soon 

 vegetated. The absence of light is as essential for germination as its 

 presence is necessary afterwards. Heat is likewise requisite. Seeds 

 remain in a torpid state when planted in winter, but the warmth of 

 spring urges them into life ; and vegetation is subsequently hastened 

 by increasing it. Germination will be as forward in six hours by in- 

 creased heat as otherwise in nine. Too great heat, however, destroys 

 the vital principle. Roasted seeds will not vegetate. Some seeds 

 germinate sooner than others, varying from one day to several years. 

 Those of grasses and grains germinate in two days ; the peach, wal- 

 nut, etc., remain in the ground a year. Seeds germinate sooner by 

 being planted on removal from the fruit. Mosses revive on being 

 soaked in water after having been kept 200 years in an herbarium. 

 Some seeds kept dry 1000 years will germinate. 



In the germination of the seed-lobe, as with wheat moistened thirty 

 hours, the smooth hard sheath becomes downy, and first presents a 

 radicle with one at each side. The gemlet appears on the lobe com- 

 posed of leafets. Small rootlets spring from the three radicles, and new 

 buds burst upward from the crown of the root. The embryo thus be- 

 ginning to grow is called the plantlet. 



Germination with two lobes first presents the radicle projecting like 

 a cone and the naked gemlet appears between the lobes. When 

 planted, or moistened in the dark a day or two, the shell is soft and 

 white, which being stripped off, the two lobes appear with the small 

 gemlet, having yellow leaves and the radicle between Ihem, while the 

 neck is united to each lobe by a small stem. The second day after 

 planting, the radicle protrudes as the shell yields ; the third day it 

 sends out rootlets, the seed-lobes separate and exhibit the gemlet. On 

 the fifth, the white stem shoots up with the green gemlet on the top. 



