Dec. 1910.] Leaf Markings of Certain Ohio Plants. 243 



LEAF MARKINGS OF CERTAIN OHIO PLANTS.* 



John H. Schaffner. 



Among the most familiar objects of our fields and gardens are 

 such plants as the red and white clover with definite Hght-colored 

 markings on the leaflets. Another equally prominent plant in 

 gardens is the ribbon-grass (Phalaris arundinacea picta), whose 

 leaves show variegated longitudinal bands of white and green color. 



Sometime ago the writer began to collect data on the native 

 and introduced plants of Ohio which show any definite type of 

 markings. The problem is rather difficult since the markings 

 usually disappear when plants are dried. It becomes necessary, 

 therefore, to become acquainted with the plants in the living 

 condition. Diuing the past year a considerable number of 

 species showing markings of various kinds have been observed, 

 and the Hst could without doubt be considerably extended. 



It has usually been customary- to ascribe some purposeful 

 eftect or utility to the markings on the animal body and to the fan- 

 tastic patterns shown by many flowers. It is open to question, 

 however, whether such an assumption should be generally applied. 

 The markings on the leaves of plants are favorable objects in this 

 connection and may throw considerable hght on the subject. 



In many species, certain individuals have the markings while 

 others lack them. There are probably elementary species present 

 which might be segregated. These forms should make interest- 

 ing material for the study of mutations and inheritance. In some 

 species the markings are only on the yoimger leaves, in others only 

 in connection with the inflorescence and thus on the latest leaves 

 to be developed. 



The markings of the leaves studied may be grouped under 

 three general heads as follows: 



1. Markings due to abnormal or diseased conditions, or 



the so-called variegations. 



2. Markings more or less accidental, depending on some 



internal structtire and evidently having no relation 

 with the development of a definite pattern. 



3. Markings which are of more or less definite patterns 



not dependent on fundimental structures. 



f nder the first group mentioned above would fall such forms 

 as Phalaris armidinacea picta, already mentioned and the numerous 

 vairegated species commonly cultivated in greenhouses. The 

 white bands or spots being due to a lack of chlorophyll in the parts. 

 White stripes are frequently to be observed in yotmg plants of 

 com, Zea mays, and occasionally the entire plant is white. These 

 latter individuals usuallv do not siu-vive long. 



* Read at the meeting of the Ohio Acad, of Sci., Nov. 25. 1910. 



