ILLINOIS NATURAL HISTORY SURVEY MANUAL 1 



their dissemination. Many akenes have no special appendages, 

 others may have tufts of hairs which are formed differently and 

 have other names, such as the feathery crown of hairs on the 

 akenes of clematis, or the coma, or tuft of hairs that rise separate- 

 ly from the seed coat of the milkweed. The seed of grass is often 

 spoken of as an akene but is more properly called a grain or a 

 caryopsis; and that of mints, in which only a part of the ovary 

 comes off with each seed, is called a nutlet. 



Winged fruits such as those of ash and maple are called 

 samaras. The larger fruits of oaks, hazel and walnuts, which 

 do not split open to shed the seeds, are called nuts, and their 

 dissemination is dependent upon animals; they are commonly 

 planted in the ground by squirrels hoarding their winter's 

 supply of food. The seed coats of many of these indehiscent 

 fruits are so hard that they must be split open by frost before 

 the seeds can germinate. 



There are still other, more complex indehiscent fruits, such 

 as the fruit of the cocklebur and burdock. These are aggregates 

 of a flower cluster and are included in the category of multiple 

 fruits. There are also fleshy multiple fruits such as the mulberry, 

 for here we have the product of a cluster of small flowers. 



Dehiscence. — The dehiscent fruits that split open to shed 

 their seeds are of many different kinds. They split open along 

 definite lines or seams called sutures. The capsule is illustrated 

 by the fruit of the poppy, the Jimson weed and the lily. Some 

 of them split open lengthwise into two or more pieces called 

 valves, they may split open crosswise as in the purslane, or they 

 may open by little pores near the top of the seed capsule as in 

 the common poppy. All these fruits are derived trom the flower 

 with a compound pistil, one which has several parts, cavities or 

 compartments. 



Follicles and pods are names given to certam truits coming 

 from simple pistils, such as the fruit of a columbine and pea; 

 the first kind splits down the inner side only, the second splits 

 down the outer side as well. The fruits of certain mustards, 

 called siligues, appear similar to the pods and follicles but are 

 in fact compound or double, often having a definite partition 

 between two halves. 



Thus the more complex terminology employed by botanists 

 implies certain important distinctions which tell us something 

 of the kind of flower and pistil which gave rise to the particular 



22 



