25° BOTANICAL GAZETTE [APRIL 
The first known publications on this subject were made by CASPARY 
(4) in 1860, when he announced that the seeds of Bulliarda aquatica 
are strongly light sensitive. In 1867 he (5) discussed the germina- 
tion of seeds of Pinguicula vulgaris. In 1876 NoBBE (38) made 
the statement that germination was neither favored nor influenced 
_ by light. After WresNER (51) had published the statement that 
the germination of seeds of Viscum album is favored by light, and 
STEBLER (48) had shown that Poa pratensis and P. nemoralis 
germinated up to 60 per cent in light and only up to 7 per cent in 
darkness, NoBBE (39) published results of experiments with grass 
seeds, including Poa pratensis, Zea Mays, and some other large 
seeds to uphold his earlier contention. PaucHon’s (41) results 
supported Nosse in the controversy. In 1883 CresLar (6) con- 
firmed and extended STEBLER’s results, reporting Agrostis stolonifera 
and Nicotiana macrophylla as light sensitive. He made a careful 
study of the influence of temperature in connection with light, and 
showed that small seeds poor in reserve materials germinate better 
in white light, while large seeds are usually indifferent to light, and 
that seeds of Poa nemoralis germinate better in yellow light than in 
violet. LiIEBENBERG (35) in 1894 confirmed STEBLER’S results, 
but referred to them as temperature effects. 
In 1893 Jonsson (23) showed that after-ripening has a definite 
influence on the action of light in germination, that light increases 
the percentage of germination, that heat rays are unimportant, 
that intermittent light is as effective as continuous light, and that 
intermittent temperature may be substituted for light in the 
germination of such seeds as Poa pratensis, P. nemoralis, Agrostis 
stolonifera, and Daucus Carota. 
In 1899 HEINRICHER (19) began publishing the results of his 
work on light germination. He (20) reported that seeds of Pit- 
cairnia maydifolia germinate only in light, that the germination 
of Veronica peregrina seeds is hastened and several other small seeds 
are favored in germination by light. He considered the factors to 
be age, quickness of drying, moisture, illumination of parent plant, 
and light of different colors. He (21) concluded that the effect 
of light is a matter of activation of reserve materials, that the 
benefit of light is not due to its causing early carbon assimilation, 
