ON THE INFLUENCE OF THE ORDER OF DEVELOP- **^-'- 

 ]MENT OF THE FRUITS OF PASSIFLORA GRA- 

 CILIS UPON THE FREQUENCY OF TERATOLOGICAL 

 VARIATIONS 



J. ARTHUR HARRIS AND ROSS AIKEN GORTNER 



Station for Experimental Evolution, Cold Spring Harbor, N. Y. 



I. INTRODUCTORY REMARKS 



Our knowledge of the proximate causes of teratological varia- 

 tions^ is so meager that any definitely established facts bearing 

 upon the problem are of value. Such facts are, because of the 

 relatively great rarity of most abnormalities, very difficult to 

 obtain. 



In this note we show that the abnormalities in the fruits of 

 Passiflora gracilis taken as a whole- are not distributed at random 

 over the plant but that in their production there is a definite 

 periodicity. 



1 Strictly speaking teratological variations cannot be sharply marked off from 

 any other kind. The term is, however, fairly well understood among botanists, 

 and the distinction of this type of variation is perhaps convenient. 



2 Some years ago one of us (Harris, J. Arthur. Prolification of the Fruit in 

 Passiflora and Capsicum. Ann. Rep. Mo. Bot. Card. 17 : 133-145. 1906) discussed 

 the phenomenon of prolification of the fruit in Passiflora gracilis. Besides prolif- 

 ication — the production of accessory fruits, or rather of a succession of whorls of 

 incompletely closed, rarely ovuliferous carpels inside the fruit — a considerable 

 series of meristic variations is to be foimd in the wall of the fruit. These consist 

 for the most part of a tetramerous instead of the normal trimerous organization — 

 that is, the production of eight external sutures, four dorsal and four placental, 

 and four placentae, instead of six external sutures and three placentae. Pentam- 

 erous and even hexamerous fruits also occur, although very rarely. Transition 

 stages between these various classes may occur, although these intermediate 

 conditions are rare. These variations in the organization of the fruit wall may be 

 combined in various ways with prolifications of fairly distinct types. 



The morphological problems presented by these teratological fruits have been 



under investigation for several years and will be the subject of a forthcoming 



memoir by one of us. When that is made ready the subject of the distribution of 



the individifal types of abnormality through the fruiting season will be taken 



into account. 



199 



THE PLANT WOKI-D, VOL. 17, NO. 7, 1914 



