354 



RELA TION TO EKVIRONMENT. 



tion of the problem in the relation of the shoot to aerial en- 

 vironment, stem and leaf have in most cases cooperated;* but 

 in view of the great varietv of stems and tlieir modifications, as 

 well as of lea\-es, it will Ije convenient to discuss them in separate 

 chapters. 



693. (2d) Shoots without foliage leaves. — Idiese are subter- 

 ranean or aerial. Nearly all sul)terranean shoots ha\'e also 

 aerial shoots, the latter being for the display' of foliage leaves 

 (foliage shoots), and also for tire displav of tlowers (flower shoot.s). 

 The subterranean kinds bear scale lea\'es, i.e., the leaves not 

 having a light relation are reduced in size, being small, and they 

 lack chlorophyll. F,.\amples are found in Solomon's seal, man- 



^ V 



Burruwmg t\'pe. the mandrake, a " rliizome." 



drake (fig. 41,317), etc. Here the scale lca\es are on the bud at 

 the end of the underground stem from wliicli the foliage shoot 

 arises. Aerial shoots vliich lack foliage lca\'es are the dodder, 

 Indian pipe-])lant, beech drops, etc. These plants are sapro- 

 phytes or parasites (see Chapter IX). ])eri\-ing their carbo- 

 h)-drate food from other li\ing plants, or from lumuis, tliev do 

 not need green lea\'es. The lea\es have, tliercforc, probably 

 been reduced in size to mere scales, and acconi|)anving this 

 there has been a lo.ss of the cliloroplull. ( )llicr interesting e.\- 

 amples of aerial slioots without loliagc lca\cs arc tlie lacti where 



■^- If is interesting to note Iliat in si mir fnliaL^^e .sIkhiIs tlii' stiaii is rntirelv 

 suhtci'raiKan. S(.a- (list nssion of the liratktn fciai and SLaisiti\'e fcni in 

 fliaptur X.XXIX. 



