YAMPOLSKY: Study of OU palm. 111 



the lamina. Thèse folds do not, however, run to the edge of the lamina. 

 They disappear and the edge of the leaf is seen as a continuous unfolded 

 strip. Partial séparation of the segments results from the drying up of definite 

 tissue when the leaf is 1 cm. long. This process begins at the apex and 

 proceeds to the sides of the leaf. 



The steps in Livistoiia are the same as for Pritchardia. 



Chaniacrops differs from the other two only in the manner in which the 

 segments partially separate from each other. This occurs through the dege- 

 neration of the cells — they become mucilaginous. The tissue of the lamella 

 that remains intact forms an epidermis around the ends of the segments where 

 séparation had taken place, 



hi Plwenix spinosa after the initial stages of leaf development, folding of 

 the lamina occurs much in the same manner as described for Pritchardia 

 — a strip at the edge remains unfolded -- the folds, however, run horizontally 

 instead of vertically as in other forms — the fan palms. Séparation of segments 

 occurs when the leaf is '/2 cm. long by a process of disorganization which 

 begins at the unfolded edge and progresses towards the middle of the 

 leaf. The rest of the forms show only slight variations. 



Naumann (^^) investigated Plioenix leoncnsis, Ph. aeqiUnoctiaLis, Pfi. 

 rcclinaia and Ph. daciylifera. Séparation of the pinnate palm leaf is a resuit 

 of splitting in the halves of the blade. 



"Der eigentlichen Spaltenbildung welche durch auseinander weichen 

 von Zellen erfolgt, geht eine Art Wulstbildung voran, âhnlich wie bei der 

 Entwicklung zusammengesetzter Blâtter der Dicotyledonen ; doch scheinen 

 Wùlste und Spalten bei Phoenix ziemlich gleichzeitig aufzutreten, da die 

 Querschnittsbilder mit dem Wiilsten zugleich auch Spalten zeigen." 



Naumann's observation differs from VON MOHL's inasmuch as he 

 describes the appearance of "Wùlste" or swellings in association with slits. 

 The slits do not run as far as the periphery of the blade. There remains a 

 smooth strip around the periphery. NAUMANN maintains that the space 

 relations between successively developed leaves is not so close as to cause 

 pressure. The space between two developing leaves is filled with a very 

 fine hair tissue. Naumann's observations lead him to combat GOEBEL's idea 

 of a secondary tissue which envelops the folds of the blade after folding 

 has taken place. According to his observations the enveloping tissue (Haut) 

 is a part of the leaf and not an accessory product. NAUMANN states that 

 the number of slits increases with the growth of the leaf; development is 

 basifugal. 



The other pinnate palms that Naumann investigated conform in the 

 main to the observations cited above. In the fan palms NAUMANN finds practi- 

 cally the same conditions as in the Phoenix' spec\QS. "Auch bei den Fâcher- 

 palmen gilt nach meinen Untersuchungen dasselbe, was ich bei dengefiederten 

 an Phoenix gezeigt, dass die gefaltete Blattspreite durch eine mechanische 

 Faltung nicht zu Stande kommt. Auch hier treten Wulste auf welche, 



