LOCALIZED STAGES IN DEVELOPMENT. 125 



pinn.ae result from the splittin.i;' apart of the leaflets, as shown iu leaves 2 and 3 of Fig. 

 lO.'i. The leaf of the adult is similar to the last formed leaf in PI. 23, fig. 103, except in the 

 increase in size, and in the nuuilier of pinnae, and in the relative reduction of the terminal 

 leaflet. In Cocox iiTedde/itnin Weiidl. (PL 23, figs. 10], 102). the development is 

 similar to that of Phoenix. 



In Cdnjota ciimiiigii Lodd. (C. iirciix Blanco) (PI. 23, figs. 97-98), the early seed- 

 leaves are deeply cleft, more so than in the seedling of any other palm known, and the 

 leaf is distally truncate and serrate as if snipped with scissors. As the plant grows older, 

 the leaves become pinnate (PI. 23, fig. 97), the distal leaflet resembling the simple early 

 leaf. Adult leaves are similar to this early compound leaf, except in size and the increased 

 number of tiie leaflets. This is, perliajjs, the most dift'erentiated type of nepionic leaf seen 

 in palms, and in its cliaracters shows a markedly accelerated development, ('ariiofd 

 riniij)]it(iii(i Mort. is similar to ('. ciniiiiH/ii in early characters. 



In palms with })innately compound leaves, in all cases where the adult and young are 

 known to me, the distal leaflet of the adult leaf corresponds closely in form to the whole 

 of the early nepionic leaf. This is the case in several species each of Phoenix (PL 23, 

 figs. 100, 103), Cocos (Figs. 101, 102), Caryota (Fig. 97, 98), Chrysalidocarpus (Fig. 95), 

 Kentia (Fig. 9C) and other genera. 



In the growth of a pinnate-leaved ])alni, when a new leaf first appears, the pinnae 

 cling together laterally on their outer margin and to the distal leailet, in such a way that 

 the whole leaf simulates the entire type and demonstrates the simple dynamic genesis of 

 this type of compound leaf from an ovate leaf like that of the young. This is shown 

 well in Dlploihemhim riKty'dliiutm Moi't. (PL 23, fig. 99), also in part of the leaflets of 

 Phoenix (Fig. 1U3, leaf 3) and Cocos (Fig. 101). A similar clinging may be seen in 

 palmate palms (PL 23, fig. 93) . An elongation of the rachis with attendant reduction 

 of leaf-tissue induces the pinnate type. A shortening of the rachis induces the palmate 

 type ; Sabal, Latania. An extreme shortening of the rachis with abundant leaf develop- 

 ment may even induce a form in whicli the leaf is radial from a central point in the 

 rachis; some species of Chamaerops. In the development of a leaf, then, there is in this 

 localized part a repetition of features seen in the young. Also the distal tip of pinnate 

 leaves repeats the form of nepionic leaves. 



Some palms sucker from the base, and in such suckers we might expect to find local- 

 ized stages in development, as is the case. In Ra/)hi>i ffabef/lfoniiix L'flerit., a fan-leaf 

 palm, suckers from the base have .simple ovate leaves like (PI. 23, Hg. 91) and only in 

 later growth are the typical fandeaves of the species acquired. I have not seen seed- 

 lings of Ji. JliiheJ/lfoniils, but the suckers repeat the form of seedlings of KapluH lannUls 

 var. eh'(j(tiis and allied genera so closely that in leaf cliaracters they are inseparable. 



