150 



THE AMERICAN BOTANIST 



variety pniiuiUmis, he has produced a new form with wine red 

 rays. This he has named vinosus. The reason for crossing 

 the chestnut-red plant with the primrose-colored one was to 

 avoid the orange tint which was rightly regarded as preventing 

 the chestnut-red from becoming clear red. In primulinus the 

 orange is lacking and the resulting cross had rays of "rich, 

 deep wine red." The new form is soon to be put on the 

 market and will no doubt do much to make the garden bright 

 in summer. 



Anthesis. — The term anthesis is used to indicate the 

 period of time in which a given flower is concerned in pollina- 

 tion. The word is sometimes taken to mean the expanding 

 of flowers, but many flowers, for example those without floral 

 envelopes — calyx and corolla — have nothing to expand. The 

 end accomplished in anthesis, is, of course, the fertilization 

 of the eggs in the young ovules and this presupposes pollina- 

 tion, but the causes that effect anthesis are many. In some 

 fl'owers it is warmth, in others light, in still others moisture 

 or some combination of these forces. In some plants the 

 opening of the flowers seems conditioned on the vegetative 

 processes of the plant, and in others, darkness rather than 

 light produces the effect. Flowers that open in the morning 

 may close at evening and open the next day, but those that 

 open at night and close at dawn are less likeh- to open again. 

 Many flowers, however, that close in the morning" in warm 

 weather may remain open all day when the weather is cooler. 

 In general there is a noticeable difference between flowers that 

 have ceased blooming and those that have closed temporarily. 

 Usually the wilting of the corrolla indicates that blooming 

 has finished but in a few cases this is no criterion. In the 

 spider flower, for example, the flowers open toward evening 

 and by mid-forenoon of the next day the petals hang limp 

 and twisted as if ready to fall from the plant. But as evening 

 approaches they unfold once more and appear as fresh as ever 



