Profited li in Sporangia of Todea. 239 
generalize from his results, but his determination of the influence of 
temperature is important Since the publication of Heald’s work, other 
papers dealing with the same subject have appeared. Burgerstein 
(’01, p. 93) found light necessary to germination. Schulz (’ 02 , p. 97) 
experimented with several Ferns, and found that the spores only germinated 
in the light, except in the case of Ceratopteris thalictroides , Hydro pterideae 
and Ophioglossaceae. Life (’ 07 , p. 121) did not succeed in germinating 
Fern-spores in the dark, even when the temperature was 30° to 33 0 C. In 
his experiments the spores were sown on leaf-mould. Laage (’ 07 , p. hi, 
&c.) made numerous experiments, using Knop-solution ( 1 per cent, and 
other strengths) and several other liquids. In darkness he obtained ger- 
mination of spores of Osmunda regalis , Pteris aquilina , Scolopendrium 
officinale (S. vulgare , Sm.), Aspidium acute atum, and A. Filix-mas, but failed 
with Asplenium lucidum , Alsophila australis , and Poly podium aureum. 
From a consideration of these numerous researches, which in one or 
two cases gave opposite results for the same species, it appears very probable 
that the failure of spores to germinate in the dark was due in some cases 
to an unfavourable temperature. With the most suitable medium and 
temperature (both of which may vary for different species) it is possible 
that most or perhaps all Fern-spores might be capable of germination in 
the dark ; but this remains to be seen. 
In Todea Fraseri germination took place in the dark in tap- water 
between 6o° and 70° F. (i6°-2i° C.), but neither the optimum temperature 
nor the best medium was ascertained. The nutrition of the spores, when 
germinating in darkness, is apparently provided by a reserve of an oily 
substance \ Spores were crushed in 1 per cent, solution of osmic acid, and 
it was found that oil was more abundant in T. Fraseri than in T. hymeno- 
phylloides . This may explain the greater readiness with which spores of 
the former species germinate, which is specially noticeable in darkness. 
The oil is probably partially converted into a soluble carbohydrate (see 
previous foot-note), which supplies the osmotic strength of the cell-sap 
necessary for germination. Definite limits of temperature for germination 
in this and other species of Ferns are probably fixed by those necessary for 
the action or formation of an enzyme, which converts the oil into a soluble 
carbohydrate and other bodies. 2 
1 Borodin (’68, p. 446) states that, on the germination of Fern-spores in the light, the oil appears 
to be transformed into starch. Schulz (’02, pp. 90, 93) observed the presence of oil in Fern-spores, 
and found in Aspidium , &c. (which he did not succeed in germinating in darkness), that the 
formation of starch began with germination in light. He obtained the same result with Ceratopteris 
in darkness. This probably indicates that a sugar is formed, and that, when it reaches its maximum 
concentration, germination begins. 
2 The physiological process may be quite similar to that described by Green (’90, p. 384, see 
also Czapek, ’05, vol. i, p. 129 et seq.) in the endosperm of Ricinus , the reserve-oil being split up by 
an enzyme (lipase, formed from a lipozymogen present in the resting spore) into a fatty acid and 
glycerine, and the glycerine being at once converted into sugar. 
