226 BOTANICAL GAZETTE {MARCH 
Chemotaxis of sperms of Equisetum.—Liprorss,°° to avoid anticipation by 
SurBata, has made a preliminary announcement of his discovery that the sper- 
matozoids of Equisetum are markedly chemotactic toward solutions of malic acid 
especially, and also to maleic acid and its salts. Only indifference is shown to 
solutions of fumaric acid or of its salts. The threshold concentration of malic acid 
he finds to be about M/1oo00. Aerotaxis, which had been previously observed in 
the case of Marchantia spermatozoids, could not be demonstrated.—RaymonD H. 
Ponp. ‘ 
Welwitschia.—Tumboa mirabilis is so little known that any fresh observations 
are welcome. PEARSON37 succeeded in securing material showing the develop- 
ment of microsporangia, microspores, megasporangia and megaspores. Observa- 
tions were made upon the habit, habitat, and climatic conditions. It is probable 
that the plant is partially, if not wholly, insect-pollinated, and that the processes of 
fertilization and maturation of the seed take place more rapidly than in other 
gymnosperms.—CHARLES J. CHAMBERLAIN. 
The cycadean integument.—This is discussed in a recent paper by Miss 
Stoprs,38 who takes this occasion to compare the structures of the cycad ovule 
with those of the fossil Lagenostoma. The single integument of the living cycads 
is regarded as a double structure representing two integuments of some ancestral 
fo The plane of fusion of the two integuments has been between the inner 
and outer layers of the stony coat, or between the stone and the outer flesh. 
—CHARLES J. CHAMBERLAIN. 
A rust-resistant cantaloup.— Birnn3° finds that the Pollock strain of canta- 
loups is resistant to the rust or blight which is a common and serious disease in 
the Rocky Ford district of Colorado. This resistance he found was transmitted 
through seed selected from resistant plants, and hence seed selection becomes a 
very practical method of controlling this destructive disease wherever it may 
occur. The disease is due to the fungus Macrosporium cucum2rinum E. & E.— 
E. Meap Witcox. 
3°LipForss, B., Ueber die Chemotaxis der Equisetum-Spermatozoiden. seg 
Deutsch. Bot. Coit 23: 314-316. 1905. 
37PEARSON, H. H. W., Some observations on Welwitschia mirabilis Hooker. 
Abstract of a communication to the Royal Society of London, Nov. 23. 1905- 
38SToPEs, MARIE C., On the double nature of the cycadean ne pee 
of Botany 19:561-566. 190 5. 
39BLINN, P. K., A rust-resistant cantaloup. Bull. Col. Agric. Exp. Stat. 104: 
I-15. pls. I-IO. 1905. 
