248 MORPHOLOG Y. 



flower, and in the number and arrangement of its members. 

 This suggests to us that there may be some kinship, or rela- 

 tionship between the lily and trillium, and between the bitter- 

 cress and toothwort. In fact it is through the interpretation of 

 these different plans that we are able to read in the book of 

 nature of the relationship of these plants. As we found in the 

 case of the ferns that the most important characters of rela- 

 tionship among genera and species are found among the spore- 

 bearing leaves, so here the characters pertaining to the stamens 

 and carpels are the principal guide posts, though the floral en- 

 velopes are only second in importance, and leaves also frequently 

 demand attention. 



Bearing these facts in mind, we can inquire of the plants 

 themselves about some of the attributes of their families and 

 tribes. 



NOTE FOR REFERENCE. 



482. Arrangement of flowers. — The arrangement of the flowers (inflores- 

 cence) on the stem is important in showing kinships. The flowers may be 

 scattered and distant from each other on the plant, or they may be crowded 

 close together in spikes, catkins, heads, etc. Many of the flower arrangements 

 are dependent on the manner of the branching of the stem. Some of the 

 systems of branching are as follows: 



483. I. Dichotomous branching. — True dichotomy (forking) does not 

 occur in the shoots of flowering plants, but it does occur in some of the flower 

 clusters. 



484. II. Lateral branching. — Two main types. 



Monopodial branching. — This occurs where the main shoot continues to 

 grow more vigorously than the lateral branches which arise in succes- 

 sion around the main stem. Examples in shoots, horse-chestnut, pines 

 (see chapter on pine). Examples in flower clusters (from indetermi- 

 nate inflorescence). 

 Raceme; lateral axes unbranched, youngest flowers near the terminal 



portion of long main axis; ex. choke-cherry, currant, etc. 

 Spike; main axis long, lateral unbranched axes with sessile and often 

 crowded flowers; ex. plantain. Where the main axis is fleshy the 

 spike forms a spadix, as in skunk's cabbage, Indian turnip, etc. ; if 

 the spike falls away after maturity of the flower or fruit it is a cat- 

 kin or ament (willows, oaks, etc.). 



