4 DESCENDING PART OF A PLANT. ROOT .

r. R, articulata or granulata, a Jointed or Gra-nulated Root, like Wood Sorrel, and WhiteSaxifrage.

9. Roots differ in duration, being either annual, bien-nial, or perennial. Fibrous and Tap Roots arefrequently annual; some Tap Roots are biennial ;Creeping, Abrupt, Tuberous, Bulbous, and JointedRoots are always perennial, as are some Fibrousand a few Tap Roots.

10. Annual Roots produce the herbage, flowers, andseeds within the compass of one season, after whichthey entirely die ; Biennial ones produce herbageonly the first summer, flowers and seeds the next,after which they also die; Perennial Roots bearherbage and flowers through several successive years,to an indeterminate extent, and moreover increase,or form offsets, either spontaneously, or with theassistance of art.

11. The Root is the first part produced by the Seed,when beginning to vegetate in the earth. It is na-turally directed downwards, extending itself at theextremity, and forming fresh fibres every year, such(7) being an essential part of every kind of root, thevegetation of which, and of the plant it bears, goingon only while the fibres continue to grow, and toimbibe nourishment.