150 PLANT STUDIES 



color. It lias l)coii statiMl tliat this green eolor is dne to 

 the presence oi' a C(iloriiiii; mutter known as rhlorophjjU 

 (see §1~). The two gi'ou|is iiuiv I"' spoken of, therefore, 

 as (1) green phinis ami (",') plajih withmt cliloroplnjll. 

 The presence <>f I'hlorophyll makes it possihle for the ]ilants 

 containing it tu iDaniifa.cture their own food (Uit of such 

 matei'ials as "water, soil nniterial, ami gases. Fur (liis 

 reason, green jjlants may l)e entirely iiidepeiidciit (jT all 

 other living things, so far as their fond siipjilv is iMuicerned. 



Plants witliout (dd(]roiihyll. howevei-, arc iinalilc to 

 manufacture fiMjd out of such matt^rials, a.nd must (jlitain 

 it already iiKiuufacturcd in Die liodies nf othei' jilants (jr 

 animals. For this rea.son, they are d(vpi>mlent upon otlier 

 living things for their fond supply, just as are a.nimals. It 

 is evident that plants without chloi-ophyll imiy olitain tliis 

 food supply either from the living hodies of plants and ani- 

 mals, in which case they are called parasites, or they may 

 obtain it from the suhstauces derived from the Ijodics of 

 2)hiids and animals, in which case thev ai'c called snjiro- 

 ■phjiles. For examjilc, (he rust which attacks the wheat, 

 and is found upon the leaves and stems of the living })hint ; 

 is a pa.rasitc, while the Jnmild which often develo[is on stale 

 bread is a- sapi'ophyte. Stmie })laid.s without chlorophvll 

 can live cither as parasites or sapri>|ihvtes, while othci's ai'e 

 always one or tlie other. F>y fai' the largest number of 

 parasites and sapi'ophytes belong to the group of low plants 

 called fungi, and when fungi are referred to, it must be 

 understood that it means the greatest gron[i of plants with- 

 out chlorophyll. 



IVl. Photosynthesis. — 'I'hc nutritive ]n'occsscs in green 

 plants a.i'c the same as in other plaids, and in add it ion there 

 is in green plants the pemdiai' process known a.s jiliolosiin- 

 thesis (see §"-■"')• -I'l plants with foliage leaves, these are 

 the chief organs for this work. It. must be rcinendicred, 

 ]iow(!ver, tJiat lea.ves ai-(! mit ncccssai'y fur photosvnthesis, 

 for plants without leaves, such as alg;e, i)erform it. The 



