RELATIONSHIPS SHOWN BY FLOWER AND FRUIT. 22/ 



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: 



371. 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. 



372. 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 succession around the main 

 stem. Examples in shoots, horse-chestnut, pines (see 

 chapter on pine). The inflorescence is termed indefinite, 

 or indeterminate inflorescence; i.e., the flowers all arise 

 from lateral buds, the main axis continuing to grow. 

 Raceme; lateral axes unbranched, youngest flowers near 

 the terminal portion of long main axis; ex., choke- 

 cherry, currant, spring beauty, 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 catkin or ament (willows, oaks, etc.). 

 Umbel; the main axis is shortened, and the stalked 

 flowers appear to form terminal clusters or whorls, as 

 in the parsley, carrot, parsnip, etc. 



Head, or capitulum; the main axis is shortened and 

 broadened, and bears sessile flowers, as in the sun- 

 flower, button-bush, etc. 



Panicle; when the raceme has the lateral axes branched 



it forms a panicle, as in the oat. When the panicle is 



flattened it forms a corymb, as in the hawthorn. 



Sympodial branching or cymose branching. The branches, 



or lateral axes, grow more vigorously than the main 



axis, and form for the time false axes (form cymes). 



