growth and division, they form most regulai, interesting, 

 and varied colonies, which make them look li^e branching 

 plants. This has given them the name of zoophytes, or 

 plant-animals. 



5. Buds in Higher Plants. It is in the common plants 

 that the student is most familiar with buds. On almost 

 every plant you have seen buds at the ends of stems, and 

 arising from the sides of stems in the angles of the 

 leaves. These side buds are very much like the buds 

 we have been describing in hydroids, that remain 

 attached lo the parent and form complex colonies. In 

 these plant buds there are tissues whiijh are continuous 

 with similar tissues of the parent stem and derived from 

 them. These buds, when they grow, develop more 

 structures, as stems, leaves, flowers, and the like, just 

 like those that are to be found on the main stem. 

 Furthermore, in a great many plants, if one of these twigs 

 be cut off and be given the proper conditions for life, 

 such a bud or twig is able to form roots and to develop 

 a separate plant just as the young hydra bud does 

 naturally. Such buds then as we see every day in plants 

 may be thought of as a kind of multiplication or 

 reproduction of the essential plant structures. The 

 student can see that this is much more than mere growth 

 as our arms or fingers grow. It is more than the 

 lengthening of a stem after it starts. It is rather as if 

 we could bud out a new arm or leg at a new place, which 

 under proper circumstances would develop all the 

 structures which the trunk has. 



In some of these plants these buds after they are 

 formed may separate from the tree naturally, fall to the 

 ground, and finally grow, take root, and form a new 

 plant. Such are the gemnae of liverworts, the bulblets 

 of ferns, or lilies, and the "sets" of onions. 



6. Practical Use of Budding. In horticulture and 

 orcharding we use this quality of the bud to propagate a 

 species. Suppose in some way we find a peculiarly good 

 individual tree of pecans, oranges, apples, peaches, or any 

 one of a great many others. Instea'd of planting its seeds, 

 we take cuttings consisting of one or more buds from 

 this tree and graft these into healthy scrub stock. The 

 stock is a stem with plenty of roots. If the grafting is 

 properly done, connection will be made with the stock in 

 such a way that its roots will supply the nourishment to 

 the choice cutting. This cutting will keep its quality and 

 not take that of the stock. Ordinarily in grafting much 

 of the scrub stem is cut away and the graft is made near 

 the roots. We may, however, graft a bud on any new 

 healthy p«rt of a tree of similar kind. Indeed one can 

 graft the buds of many varieties of apple or peach on one 

 stalk, and get as many different kinds of fruits from one 

 tree. Budding and grafting are highly prized methods 

 of artificial reproduction, and they depend upon this 

 natural process of bud formation in the plant, which is 

 itself a kind of reproduction. 



CHAPTER FIVE. 



REPRODUCTION BY SPORES 



1. Another Kind of Division. In budding in yeast you 

 studied a form of division in which the protoplasm of the 

 mother cell pushed the old wall before it. This wall and 



material became a part of the structure of the new 

 daughters. There is still another way in which the 

 protoplasm of the mother cell makes daughters. In this 

 everything takes place inside the old mother wall. It 

 does not pouch out as in the yeast nor divide into two as 

 in the bacteria. The method is called internal cell-division. 

 In such a case we have an ordinary cell, or it may become 

 very much enlarged. At the outset it may have just one 

 nucleus and the usual structures found in a cell. As the 

 cell matures and grows, the nucleus divides into two, 

 these into four, and so on until there are many small 

 nuclei lying in this single mass of protoplasm surrounded 

 by a single cell wall. 



Up to this point there may be no trace of any walls in 

 the interior. The nuclei become scattered through the 

 protoplasm. The protoplasm nearest each nucleus rounds 

 off about it. A little later each little ball of protoplasm, 

 containing one of the daughter nuclei, forms a very 

 delicate membrane about itself. We have now many 

 complete though small cells, with walls of their own, 

 inside the old parent cell wall. These small cells are 

 spores. As they ripen, the wall of the spore becomes 

 firmer, the old mother wall breaks down, and the spores 

 are thus set free. 



Spores such as are described above are found in many 

 of the algae and fungi 



2. The Nature of the Spore. A spore differs from the 

 small budded daughter cells of the yeast, for example, in 

 this: The spore is merely a reproductive cell. It does not 

 look like the plant from which it came. Furthermore it 

 takes no part in getting itsi own nutrition, as the yeast 

 bud does. It is nourished by the parent until it is ripe. 

 The yeast bud looks like its parent plant from the 

 beginning, only smaller. Whether spores are formed 

 internally, as described above, or externally, somewhat as 

 yeast buds are formed, they are always just single cells 

 with the power to develop into a plant like the mother. 

 They are not small editions of the plant itself. 



3. What of the Original Cell? In the forming of spores 

 the old parental wall is left behind, and sometimes there 

 may be fragments of the old protoplasm that did not 

 enter into any of the spores. These things represent what 

 is left of the parent cell. There is not enough vitality in 

 these remnants to enable the mother cell to continue its 

 life and to reproduce again. It is destroyed just about as 

 effectively as in fission, in which all the mother substance 

 goes to the daughters. 



The advance that is found in this method over simple 

 fission is not in preserving the parent cell and reducing 

 the degree of sacrifice, as was true of budding; but rather 

 it enables one cell in its destruction to produce many 

 young instead of two. This means a much more rapid 

 increase of the species, if only the spores are well enough 

 endowed to carry on the work. 



In addition to the advance mentioned above, it often 

 happens that there are other cells of the parent plant left 

 that did not take direct part in making the spores. Such 

 parts may later give rise to more spore-producing cells, 

 and thus the organism may reproduce many times. 



4. Many Kinds of Spores. Time would fail us if we 

 should undertake to describe all the different kinds of 

 spores we find among plants. We say "among plants" 

 because animals rarely reproduce by spores. There are 

 very few lowly animals that produce spores, but they are 

 so lowly that we scarcely know whether to c^Il them 

 plants or animals. On the other hand, practically all 

 plants form spores. 



While most spores are formed as described above, 

 inside the old mother cell wall, this is by no means always 



