110 Bulletin Jard. Bot. Buitenzorg, Série 111, Vol. V. Livr. 2. 



HOFMEISTER ('^) in a very brief discussion of the palm leaf says the fol- 

 lowing: "In ail palms each leaf during its development is tightly enclosed in the 

 sheath of the next older leaf. The lamina of the leaf is closely pressed in 

 this conical space. In palms with pinnate leaves {Phoenix dactylifera) both 

 halves of the lamina are arranged in folds which lie at right angles to the 

 long axis of the leaf. In fan palms (Cliamaerops hiiinilis) the leaf blade is 

 folded to correspond with the number of segments in the mature leaf." 



Séparation of the leaflets in the pinnate palm, in the compound leaf 

 {Caryota) or partial séparation of the segments of the fan palm results from 

 the death of definite tissue between the segments causing complète or 

 partial libération of the segments. 



OOEBEL n in his gênerai dicussion in "Vergleichende Entwicklungs- 

 geschichte der Pflanzenorgane" présents his contribution to the study of 

 palm leaf development : "The parts of the leaf blade are not the resuit of 

 branching of the leaf blade but arise from the division of the blade 

 into definite segments foUowing the death of the tissue which holds thèse 

 segments to-gether." 



GOEBEL investigated Chamaerops Iminilis (macrocarpa) and Phoenix 

 reclinata. 



"Young leaves of Chamaerops show parallel ridges on both sides of the 

 leaf — the ridges on one side alternate with the ridges ontheother. This is 

 the first indication of the longitudinal folding of the leaf which one can see 

 more clearly in a cross section of a somewhat older leaf." GOEBELstates that 

 the segments are set free as a resuit of the death of tissue between the segments. 

 The folds of the leaf do not reach as far as the periphery of the blade. 

 it is characteristic in young leaves that the segments are not free. They are 

 enveloped by a many-layered sheath which can be removed and which is 

 continuons with the base of the leaf blade. The sheath Chamaerops 2Lnd Phoenix 

 is the so called ligula. This ligula is not présent in ail palms. In palms 

 (without ligula) the folds in the young stages are free and the sheath which 

 later envelops them is a secondary outgrowth. 



"Woher nun dièse Haut stammt, habe ich, wegen .Mangel an Material 

 nicht feststellen kônnen, sie kann durch innige Verwachsung der oberen 

 Theile der Blatt-falten oder durch Verwachsung derselben mit dem einge- 

 schlagenen Blattrande resp. einer Wucherung derselben, oder durch Verwach- 

 sung mit einer von der Blattbasis der sich entwickelnden Schuppe entstehen etc.'' 



ElCHLER (^) investigated both great groups of palms, fan and pinnate 

 leaved. in the first group he investigated Pritchardia filifera HORT., Livistona 

 aiistralis Mart. and Chamaerops humilis L. In the second group he examined 

 Phoenix spinosa Thonn., Caryota urens L., Cocos Romansoffiana Cham. and 

 Chamaedorea ob Ion gâta Mart. 



In Pritchardia the initial stages correspond with those of other investi- 

 gators. Then immediately as a resuit of accelerated growth in width folding 

 occurs, visible as a number of furrows on the inner and outer surfaces of 



