MORPHOLOGY 



19 



the move rudimentary leaves, and, overarching the vegetative cone, 

 form a BUD. Buds are therefore merely undeveloped shoots. If they 

 are to remain for a long time undeveloped, as for example is the 



PIG. 17. Apex of u. shoot of a phanerogamic 

 plant, v, Vegetative cone ; /, leaf rudiment ; 

 g, rudiment of an axillary bud. (x 10.) 



FH:. 18. Longitudinal section f :i 

 bifurcating shoot (;>) of I./ico- 

 podlum alpinimi, showing equal 

 development of the rudimentary 

 shoots, p', p" ; b, leaf rudiments ; 

 c, cortex; /, vascular stninds. 

 (After HF.UKI.MAIKK, x i>0.) 



case with winter buds, they are protected in a special manner during 

 their period of rest. 



The Origin of New Shoots. The formation of new growing 

 points by the bifurcation of an older growing point, in a manner 

 similar to that already described for Dictyota dichotoma (Fig. 8), occurs 

 also in the lower thalloid Hepaticae (Riccia 

 fluitans, Fig. 10). Among the Cormophytes 

 this method of producing new shoots is of 

 less frequent occurrence, and is then mainly 

 limited to the Pteridophytes, and is typically 

 shown only in some Lycopodiaceae. In this case, 

 whenever a shoot is in process of bifurcation, two 

 new' vegetative cones are formed by the division 

 of the growing point (Fig. 18). In most of the 

 Lycopodiaceae the new shoots thus formed de- 

 velop unequally ; the weaker becomes pushed 

 to one side and ultimately appears as a lateral 

 branch (Fig. 19). Although a relationship as re- 

 gards position is generally apparent between the origin of leaves and 

 the lateral shoots, in the system of branching resulting from such a 

 bifurcation of the vegetative cone this connection does not exist. 

 In the more highly developed Bryophytes, particularly in the true 

 Mosses, new shoots arise obliquely below the still rudimentary leaves 



FIG. 19. Hifurcating shoot 

 (p) of Lycofniilhitii hin i" 

 datum, showing unequal 

 development of the rudi- 

 mentary shoots, ]>', p" ; 

 b, leaf rudiments. (After 

 HEGKLMAIF.R, x 40.) 



