SPKCIAL PART: THK CHLOROPHYLL APPARATUS. 7 



was determined by inspection only, and all chloroplastids that from com- 

 parison were seen to IK- normally colored were classed as beinii' functional 

 and were considered as having adequate amounts of li.u'ht and of air. 



The following plants were passed under observation during" the course of 

 this study: Aster spinosus Be. nth.; l>accliaris eiuoryi (iray; Cell is frallida 

 T< >rr. ; C ivvv/.v.i,' i^ an tens Kn.^lm . ; ( \ida/ia s fiat hit laca (iray; ( 'oril/cii Iridoitata 

 Vail; /:/>//((//'(! antisyphilitica C. A. Meyer; Foiu/incria sfilt'tidetis Eni^lm.; 

 Frauscria i/innosci (ira\-; J\'<r/>rr/i>ii(i sfiiiiosa Zncc.; Kramcria cauescois (.ira\-; 

 Olncva lesota (iray; Parkinsonia aculcata L.; Parkinsonia microphylla Torr.; 

 /\u lei /i son i a torrcyaua A Vat son; /V<w/>/.s- vetutmaWooton] Sa/t'.v tt/^nt Marsh.; 

 Samfriii'its nif \ii~ana F'resl.; Zizypktts parryi Tor? . 



SPECIAL PART: THE CHLOROPHYLL APPARATUS. 



ASTER SPINOSUS; BACCHARIS EMORVI. (Fig. i.) 



These ]ilants inhabit the wash alon.u' the river and the irrigating' and 

 \va\-side ditches, where water is frequently to be found. Aslcr sfiiiiosHS is 

 an annual with perennial root; /lacc/taris c/i/orvi is ]>erennial. Both Aster 

 and Ji(ur//an's are usually devoid of leaves, but the youn.^ portions at least 

 are supplied with rudimentary ones. 



FIG. i. Baccharis emoryi: A, segment from transverse section of young 

 stem to show the character of cortical chlorophyll band (ck.b.) ; B, sec- 

 tion of leaf, magnified as in A.* 



Chlorophyll of the stem is confined to the cortex in both species and in 

 both the chlorenchyma is palisade. The palisade in the stems of each also 

 closely resembles that in the rudimentary leaves of the same species. This 

 similarity in the structure of the chlorophyll band* in the stem and of the 



*In all figures chlorophyll is indicated by stippling. 



