Volume 14 Number 8 



The Plant World 



A Magazine op General Botany 

 AUGUST, 1911 



FRONDESCENCE AND FAvSCIATION. * 

 By Henri Hus. 



It is but natural that forms which show striking morpho- 

 logical changes should attract our attention more readily than 

 do others, color variations perhaps excepted. Thus it required 

 no great effort to find the abnormal dandelion shown in fig.l. 

 It was observed in the spring of 1910 at Ann Arbor, i\Iich., on 

 a plant growing in an empty lot in a spot level with and within 

 a few inches of the sidewalk. During 1909, specimens of both 

 Taraxacum officinale and T. erythrospermum growing here 

 had shown numerous fasciations, especially during the early 

 part of the summer. Throughout 1910 fasciations in this 

 species were few and far between in this same locality, though 

 in other species, especially in Linaria vulgaris, they were fre- 

 quent, though lacking, or at least so few as to escape 

 observation, during 1909. In this particular lot I found but 

 a single fasciation, in the latter part of the year, when, 

 during the preceding week and more especially ten days earlier 

 an exceptionally heavy rain had fallen. 



The abnormality in the capitulum illustrated, perhaps 

 analogous to that recently described for Gossypium, f is due 

 to the foliaceous development of the outer row of scales of the 

 involucre. *••' De Candolle tt described a similar abnormality 

 in Centaurea Jacea which he recognized as the variety phyllo- 



♦Contributons from the Botanical Laboratory of the University of Michigan, No. 122 

 tAl'.ard, H. A.. An Abnormal Bract Modification in Cotton. Bot. Gaz. 49: 303 

 Fig. 1910. 



* *This abnormality is mentioned by Penzig, Pflanzen Teratologic, 2 99 for both T. officin- 

 ale and T . palustre and for the first species also by Masters, Vegetable Teratology, 243. 

 T tProd. 6: SI. 



