For March, 1920 



115 



THE QUESTIONNAIRE 



Subscribers arc iinited to malcc free ttse 

 of this department to solve problems that 

 vtay arise in their garden work. Questions 

 on the ordinary pursuits of gardening, that 

 can be readily answered by applying to the 

 usual reference books should not be re- 

 ferred to the Questionnaire. 



Can you explain what produces the 

 various shades and colorings in our flow- 

 ers, especially the various tints such as 

 appear in the iris and gladiolus. 



H. S., Wisconsin. 



It is generally well known that the origin 

 of color in connection with everything on 

 the earth is the sun's rays. These rays con- 

 tain certain primary colors which are sep- 

 arated and manifested in the rainbow, and 

 which can also lie artificially separated by 

 glass. Color, as we see it on iiower petals, 

 for instance, results from the play of sun- 

 light upon a surface which rejects or ab- 

 sorbs certain rays. Ditiferences in the color 

 of flowers, or parts of flowers, are caused 

 by their having the power of absorbing cer- 

 tain rays and rejecting others; also they 

 have the power of absorbing or rejecting 

 more of one ray than of another. The 

 great botanist, de CandoUe. divided flowers 

 into two classes, which he designated xan- 

 thic (ranging from yellow to red) and 

 cyanic (ranging from blue to red). Plants 

 in the xanthic class never have blue flowers 

 (or a color which is termed blue, as pure 

 blue does not exist in flowers), nor do 

 those in the cyanic ever produce yellow 

 ones. Therefore, so far as our present 

 knowledge goes, the production of a blue 

 rose or a yellow aster is an impossibility. 

 While this division of flowers into two main 

 classes is no doubt correct as far as it goes, 

 it has certain limitations which would take 

 up too much space to discuss now. 



The power of flowers — within the range 

 of their fi.xed limitations — to absorb or re- 

 ject certain color rays depends apparently to 

 a great extent upon climatic conditions. In 

 addition to color rays from the sun, the 

 earth also receives from it actinic (chemi- 

 cal), and thermal (heat) rays, and there 

 appears to be no doubt that the action of 

 all three have considerable influence upon 

 floral colors. Obviously the prevailing con- 

 dition of the atmosphere in a certain cli- 

 mate has much to do with the prevailing 

 color of flowers native of that region. The 

 intensity and brilliancy of alpine flowers, for 

 example, is no doubt due to the clearness 

 of the atmospliere, allowing color rays to 

 reach them in a state of almost perfect 

 purity. That the thermal rays have some 

 effect upon color appears evident from the 

 fact that in the temperate zones native flow- 

 ers principally belong to the cyanic series, 

 while those indigenous to the torrid are for 

 the most part xanthic. Of course, flowers 

 belonging to both classes are to be found in 

 the same region, and in this connection 

 neither the xantliic nor the cyanic series can 

 claim the respective yellow and blue in 

 absolute purity, because among flowers, yel- 

 low is associated with both these divisions, 

 and a true blue scarcelv or ever appears at 

 all. 



That atmospheric and climatic conditions 

 do have some effect upon the color of flow- 

 ers of the same species has been jiroved. A 

 few years ago some seeds of the Tall Nas- 

 turtium produced in Britain were sown 

 near Pretoria, South Africa. It need 

 scarcely be said that the flowers of this 

 plant range from yellow through various 

 orange shades to scarlet. From the result- 

 ing plants seeds were saved and in three 

 years the flowers produced were all purple. 



No — You Are Wrong 



The Ten -Ten 



Is Not That Kind of a Catalogue 



It's not that kind of a catalogue at all. If it was, it "wouldn't 

 be your kind. 



We made it the way it's made, because that's the way We 

 thought you and your friends wanted it. 



!f we didn't understand you right, then we sure have made 

 a mess of it. 



How^ever, those who have seen the advance proofs of it, 

 haven't been slow^ to declare it was something distinctly new 

 in the seed and nursery field. 



Of course, if you want to stick to your old catalogues, just 

 like you do to your old friends; that's just fine. We wouldn't 

 think much of you if you didn't. But you make some very 

 delightful new friends every once in a while, don't you? Those 

 new^ ones don't make you drop the old ones, do they? 



Well, then, why not add a new friend in this new Ten-Ten 

 catalogue ? 



20 



Seeds of these were taken back to and sown 

 in Britain and from these purple flowers 

 have lieen continually produced. Tliis shows 

 that the new power of the nasturtium pet- 

 als to absorb other color rays, which power 

 was ac(|uircd under the South .-Xfrican sun 

 in an atmosphere of great clearness, had be- 

 come li.xed in three years. 



Some ex|)eriments were carried out a few- 

 years ago with a view to elucidating the 

 effect of different degrees of sunlight upon 

 floral colors. Flowers were screened arti- 

 ficially in such a way as to prevent the 

 direct rays of the sun falling upon them 

 during certain periods of the day. Without 

 going into details, it may be stated that it 



uliuy t^eKr5* Cor 



Ai Tho Si^ of The Trgg 



tkerfoi-d N.J. 



soon became apparent that three colors — 

 yellow, red and purple — were associated 

 with distinct altitudes of the sun as it moved 

 from sunrise to siuiset. If a plant was given 

 full sun at a low altitude any power of 

 absorbing yellow it possessed was intensi- 

 fied ; while purples could only be produced 

 by tlie sun at iis highest summer altitude, 

 and reds at the intermedialo altitudes. The 

 experiments were carried on under the cli- 

 matic conditions of the north temperate 

 zone. These results have been found to be 

 true in other directions for seasonal as well 

 as diurnal changes in the sun's altitude. 

 Some additional proof may be advanced by 

 the fact that the majority of plants bloom- 



