Groups into Which Plants Naturally Fall 459 



situations, though sadly diminished in number and size, and re- 

 duced to the position of undergrowth, by the insistent and success- 

 ful competition of a still higher group, the Flowering Plants. 

 The three divisions they have developed are also shown by the tree. 



The Flowering Plants, called also Seed-plants, or Spermato- 

 phytes. — These are all the rest of the plants of the earth, com- 

 prising all of the loftiest trees, practically all of the shrubs, and 

 the innumerable flower-bearing herbs no matter where found, 

 whether in woods, fields, waters, plains, mountains, deserts, or 

 sea-shores. In shapes they are manifold, though usually dis- 

 playing the characteristic differentiation into root, stem, leaf, 

 flower, and fruit, the functions of which are now well known to 

 the reader; but these parts may be modified multifariously in 

 form, size, and combinations in adaptation to particular condi- 

 tions of life. In size they range from the Redwoods, over three 

 hundred feet high and thirty feet through, down to some Duck- 

 weeds, hardly larger than the head of a pin. In color, since they 

 make their own food, they are typically green from the presence of 

 chlorophyll, though some have become parasites and lost it; but 

 in some special parts, notably flowers and fruits, they have de- 

 veloped well-nigh all the shades of the rainbow in adaptation to 

 the accomplishment of particular functions. In their cellular 

 structure they are developed beyond all other groups in special- 

 ization and division of labor, which is a reason for their obvious 

 and growdng dominance in all situations. Their reproduction is 

 chiefly through seed-formation (whence the name of the group), 

 following upon the fertilization of an egg-cell in the ovule by a 

 male cell brought by a pollen-tube, as already very fully described 

 in our chapter on Reproduction. 



This fertilization arrangement, whereby a male cell is carried 

 by a tube from a pollen grain to an egg-cell borne high on a plant, 

 seems at first sight to possess nothing in common with that in the 

 Fern-plants, where the male cell swims freely to the egg-cell 

 through water caught under a prothallium pressed close to the 



