1895.] Vegetable Physiology. 749 
VEGETABLE PHYSIOLOGY. 
Woronin on Sclerotinia.—Dr. Woronin who was formerly asso- 
ciated with De Bary and whose beautiful studies of the life history of 
the smut fungus, Tuburcinia trientalis at once placed him among the 
very foremost investigators in a difficult field, continues to unravel in- 
teresting life histories of the pleomorphic fungi. Some years ago he 
published valuable researches on the Sclerotinia diseases of Vaccinium 
berries, and now distributes an important paper on the Sclerotinia dis- 
ease of the bird cherry and of mountain ash. This paper (Die Sclero- 
tinienkrankheit der gemeinen Traubenkirsche und der Eberesche, Selero- 
tinia padi und Sclerotinia aucupariae) is a quarto of 27 pages illustrated 
by five superb lithographic plates. It is printed in Mém. de? Acad. imp. 
de St. Petersbourg, VIII, sé., Class Physico-Mathematique, Vol. II, No. 
1. S&S. padi attacks and kills young leaves, fruit and stems of Prunus 
padus, on which the grayish, pulverulent conidia soon appear. On the 
host plant these conidia cause a distinct almond-like odor similar to 
that of the flowers, but no such odor could be detected when the fun- 
gus was grown on artificial media. Growing on the mountain ash the 
conidia of S. aweupariae cause an odor resembling that of the flowers 
of that tree. The apothecia of S. padi appear in the spring on the 
fallen, mummified fruits. Paraphyses and asci are always borne by 
distinct hyphae, the ascogeneous hyphae being stronger and thicker. 
The ascospores have two envelopes, an outer delicate one which is cast 
off in water and subsequently becomes gelatinous to complete disap- 
pearance, and an inner, colorless, thick-walled truemembrane. When 
germinated in pure water the ascospores soon begin to form chains of 
small round spermatia-like sporidia, and the conidia behave in the 
same way. Ascospores sown in nutrient media or on the host send out 
strong germ tubes, but conidia or ascospores taken from nutrient media 
and put into pure water stop the production of hyphae and begin to 
form the above mentioned sporidia. In nutrient media an abundant 
conidial fructification was developed from ascospores in 3—4 days, and 
this was exactly like that observed in nature. Direct experiment with 
ascospores showed that the leaves are infected as they emerge from the 
bud, the stems being browned and killed by a secondary infection, just 
as peach twigs are destroyed by Monilia fructigena, only in case of the: 
1 This department is edited by Erwin F. Smith, Department of Agriculture, 
Washington, D. C. 
