THE PLANT BODY 1 7 



nation. It ends with death — that is, when no life is left 

 in any part of the plant, and only the seed or spore 

 remains to perpetuate the kind. In a bulbous plant, as a 

 lily or an onion, the generation does not end until the bulb 

 dies, even though the top is dead. 



When the generation is of only one season's duration, 

 the plant is said to be annual. When it is of two seasons, 

 it is biennial. Biennials usually bloom the second year. 

 When of three or more seasons, the plant is perennial. 

 Examples of annuals are pigweed, bean, pea, garden sun- 

 flower; of biennials, evening primrose, mullein, teasel; of 

 perennials, dock, most meadow grasses, cat-tail, and all 

 shrubs and trees. 



Duration of the Plant Body. — Plant structures which 

 are more or less soft and which die at the close of the 

 season are said to be herbaceous, in contradistinction to 

 being ligneous or woody. A plant which is herbaceous to 

 the ground is called an herb; but an herb may have a 

 woody or perennial root, in which case it is called an 

 herbaceous perennial. Annual plants are classed as herbs. 

 Examples of herbaceous perennials are buttercups, bleed- 

 ing heart, violet, waterlily, Bermuda grass, horse-radish, 

 dock, dandelion, goldenrod, asparagus, rhubarb, many 

 wild sunflowers (Figs. 11, 12). 



Many herbaceous perennials have sho7't generations. 

 They become weak with one or two seasons of flowering 

 and gradually die out. Thus, red clover usually begins to 

 fail after the second year. Gardeiiers know that the best 

 bloom of hollyhock, larkspur, pink, and many other plants, 

 is secured when the plants are only two or three years 

 old. 



Herbaceous perennials which die away each season to 

 bulbs or tubers, are sometimes called pseud-annuals (that 



