20 TKBM OV Pl^HT LIFE. 



84. SiAaEa of plant life. The successive phenomena of vegetation 

 are germination, growth, flowering, fruit-bearing, sleeping, dying ; and 

 we may add along with these, absorption, digestion, secretion. The 

 development of every plant, herb or tree, commences with the minute 

 embryo, advances through a continual series of transformations, with a 

 ^gradual increase of stature, to its appointed limit. 



85. The life of the plant is a biogeapht. Its form is novcr permanent, 

 but changing like a series of dissolving views. The picture which it presents to the 

 eyo to-day differs, perhaps imperceptibly, from that of yesterday. But let the views 

 be successively sketched when it sprouts from the seed in spring, when clothed in 

 its leafy robes, when crowned with flowers, when laden with ripe fruit, and wheD 

 dead or dormant in wmter — and the pictures differ aa widely as those of species the 

 most opposite. 



86. The term on period of plant life varies between wide extremes, 

 from the ephemeral mushroom to the church-yard yew, whose years are 

 reckoned by thousands. The term of life for each species is, of course, 

 mainly dependent on its own laws of growth, yet is often modified by 

 the climate and seasons. Thus the castor oil bean (Ricinus) is an 

 annual herb in the Northern States, a shrub in the Southern, and a 

 tree forty feet in height in its native India. 



87. Flowering and FRniT-BBAEiNO is an exhausting process. 

 If it occur within the first or second year of the life of the plant it 

 generally proves the fatal event. In all other cases it is either prt^ 

 ceded or followed by a state of needful repose. Now if flowering be 

 prevented by nipping the buds, the tender annual may become pereii- 

 nial, as in the florist's treo-mignionette. 



88. We distinguish plants, as to their teem of life, into the an- 

 nual ((X), the biennial ((g)), and the perennial {%). 



89. An annual herb is a plant whose entire life is limited to a single 

 season. It germinates from the seed in spring, attains its growth, blos- 

 soms, bears fruit, and dies in autumn, as the flax, corn, morning-glory. 



90. A biennial herb is a plant which germinates and vegetates, bear- 

 ing leaves only the first season, blossoms, bears fruit, and dies the second, 

 as the beet and turnip. Wheat, rye, &c., are annual plants, but when 

 sown in autumn they have the habit of biennials, in consequence of the 

 prevention of flowering by the sudden cold. 



91. MONOCAEPIO HEEBS. The century plant (Agave), the talipot palm, &c., are 

 so called. They vegetate, bearing leaves only, for many years, accumulating ma- 

 terials and strength for one mighty effort in fructiflcation, which being accomplished, 

 they die. But although the vital principle is extinguished in the parent, it survives 

 multiplied a thousand fold in the seed. 



92. Perennial plants are such as have an indefinite duration of 

 life, nsnally of many years. They may be either herbaceous or v/oody. 



93. Herbaceous perennials, or perennial herbs, are plants whose 



