Plants as Affected by Excessive Light. 145 



SECTION IV. PLANTS AS AFFECTED BY UNFAVORABLE 

 LIGHT. 



A BY EXCESSIVE LIGHT. 



235- The Unobstructed Rays of the Sun are often 

 Injurious to young seedlings, to unrooted cuttings and 

 to plants recently 

 transplanted. It is dif- 

 ficult to separate the 

 influences of light and 

 heat, since the heat is 

 usually greatest where 

 the sun's rays are 

 brightest ; but bright 

 light probably stimu- 

 lates transpiration (74) FIG. 61. Lath screen used for shad- 

 v ' ing cold-frames and tender plants in 



independent of heat the open ST U ^- ( A er Bailey.) 

 and thus tends to exhaust the plant of water. Various 

 devices are used to break the force of the solar rays. 

 In out-door culture, screens of lath (Figs. 61, 62), 

 cloth or brush (Fig. 63) are often placed over beds con- 

 taining cuttings or ten- 

 der seedlings, as of 

 many con e-b earing 

 trees. Cuttings in the 

 nursery may be shaded 



FIG. 62. Shed screen built of three- h v ennnnrtino- a hnarrl 

 inch-wide slats, for shading tender ^ Supporting a DOarc 

 plants and for storing pots and nvpr fU p rnw nri cVmrt 

 boxes of slow-germinating seeds. OVer tne row > n S 



stakes (Fig. 64), so as 

 to protect them during the warmer hours of the day. 



