382 



SCIENCE 



[N. S. Vol. XXXVII. No. 949 



The Periodicity of AlgcB: E. N. Teanseau, Illi- 

 nois State Normal School. 



The preliminary observations on algal period- 

 icity given in this paper are based upon a study 

 of eighteen hundred collections made at many 

 stations in eastern Illinois during the past five 

 years. The general richness of the waters of this 

 region may be judged by the fact that the genus 

 (Edogonium is represented by more than forty-five 

 species and Spirogyra by thirty-five. Field ob- 

 servations indicate that sexual reproduction in 

 nature is induced by a more definite combination 

 of environmental factors than asexual, since the 

 former is usually restricted to a short period of 

 time, while the latter may occur at intervals or 

 continuously throughout the vegetative period of 

 the algae. 



On the basis of the time of greatest frequency, 

 duration of the vegetative cycle and time of repro- 

 duction, algse may be classified as follows: 



1. Spring Annuals. — Forms whose vegetative pe- 

 riod begins in late autumn, reaches its maximum 

 in April and May and is followed by a decline in 

 June. Fruiting occurs in April, May and June. 



2. Summer Annuals. — Vegetative period begins 

 in spring, culminates in July and August, followed 

 by decline in autumn. Fruiting occurs in July, 

 August and September. 



3. Autumn Annuals. — Vegetative period begins 

 in spring and early summer, culminates in autumn, 

 decline comes with the beginning of freezing tem- 

 peratures. Fruiting occurs in October and No- 

 vember. 



4. Winter Annuals. — Vegetative period begins 

 in autumn, continues through the winter under the 

 ice and culminates in early spring. Fruiting 

 occurs from November to April. 



5. Ephemerals. — Forms having a vegetative pe- 

 riod of a few weeks or days. Fruiting occurs at 

 intervals during all but the winter months. 



6. Perennials. — Vegetative period continuous with 

 irregularly distributed maxima. Reproduction 

 takes place during the spring, summer and 

 autumn. 



7. Irregulars. — Forms in which the combinations 

 of conditions necessary for good vegetative devel- 

 opment and reproduction occur at irregular inter- 

 vals, usually of more than a year's duration. 



Algae fruit most abundantly during periods of 

 high water following favorable conditions for 

 vegetative development, rather than during periods 

 of "concentration of the water," "drying up of 

 the ponds, ' ' or the coming of ' ' hard conditions. ' ' 

 The drying up of pools may coincide with the 



fruiting of many vernal species, but it results in 

 decreasing the number of spores formed and the 

 number of species that fruit. 



The time of fruiting of many algffi is dependent 

 upon combinations of environmental factors rather 

 than on ' ' hereditary rhythm. ' ' 



A more complete account of these observations 

 will be found in the Transactions of the American 

 Microscopical Society, Vol. 32, No. 1, 1913. 



On the Presence of Diastase in certain Red Algce: 

 E. T. Bartholomew, University of Wisconsin. 

 In the Floridew, starch granules are deposited 

 outside the chromatophores. The granules do not 

 usually give the characteristic reaction when sub- 

 jected to iodine or zinc ehloriodide, but instead 

 turn brown to wine-red. To determine whether or 

 not a diastase is present which will act in the 

 ordinary way on the starch of green plants, ex- 

 tractions were made from the following: Poly- 

 siphonia variegata, Ceramium sp., Dasya elegans 

 and Agardhiella tenera. A cornstarch paste was 

 treated with various concentrations of these ex- 

 tracts, and after given periods of time tested with 

 Fehling's solution and with iodine. The results 

 showed that although starch digestion was much 

 slower in the tubes treated with the algal extract 

 than in those treated with common commercial 

 diastase, yet the digestion went on and in time 

 was complete; usually taking from six to nine 

 days. In the tubes treated with the algal extract 

 the iodine color-reactions showed that probably a 

 series of dextrins was formed before the starch 

 was completely digested. No doubt the great vis- 

 cosity of the algal extract materially retarded its 

 action on the paste. By running a series of con- 

 trols, careful check was kept on each set of experi- 

 ments. It appears, therefore, that there is present 

 in the Floridew a diastase similar to that found 

 in green plants. 



Cytological Studies on Sphceroplea: E. M. Gil- 

 bert, University of Wisconsin. 

 Investigation has shown that many statements 

 made by Klebahn and Golenkin with regard to 

 Sphceroplea are inaccurate. 



No conspicuous pit-like depressions have been 

 found in partition walls as described by Golenkin. 

 Cleavage, in the formation of eggs, begins with 

 constrictions from the plasma membrane, and cuts 

 the cell contents into masses of varying sizes. All 

 stages, from those having a single row of large 

 eggs to those having a double row of small eggs 

 may be found in one filament, indicating the possi- 



