630 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Plum-leaf Fungus. — This fungus, Septoria cerasina Pk., first becomes 

 conspicuous to a careful observer about the middle of July. It starts at 

 isolated points on the leaf-blades, apparently from spores derived from the 

 air, and spreads into a circumscribed area, usually not exceeding one-eighth 

 of an inch in diameter, and more commonly but half that size. The spots 

 are usually more or less rounded, but may be angular when bounded by 

 veins. The fungus produces three sets of spores at different seasons of 

 the year ; the septoria-spores in summer, the phoma-spores in winter, and 

 the ascospores in spring. It is reasonable to suppose that the three sorts 

 of spores have three diverse and important offices to perform. As to the 

 ascospores, they germinate upon the leaves of the plum-tree in spring, and 

 start the new growth that some time afterward bears the septoria-spores. 

 The phoma or winter spores may be of sexual nature, and perform the office 

 of the male element in originating the ascophorous stage of development. 



New Genus of Ascomyeetes.*— Herr H. Zukal describes the new genus 

 Baculospora with the following characters : — No stroma ; mycelium very 

 transient, and feebly developed. Perithecia half imbedded, membranous, 

 pellucidly yellow. Asci club-shaped, apiculate, with greatly thickened wall, 

 and eight cylindrical brown ascospores. The only species, B. pellucida, 

 was found on horse-dung. 



Ancylisteae and Chytridiacese.f — Pursuing his investigations on these 

 groups of fungi, Herr W. Zopf finds that a convenient mode of culture is 

 on pollen-grains in water. He was in this way able to follow out the life- 

 histories of Lagenidium pygmaeum and BMzopJiidium Bollinis-Pini. The 

 germinating tube of the swarmspore readily penetrates the membrane of 

 the pollen-grain, and developes into a spherical, ovoid, or kidney-shaped 

 bladder, which is transformed into a sporange, within which swarmspores 

 are again formed. After some days the sexual organs are also produced. 

 An undescribed species of BMzopJiidium he finds parasitic on a diatom, 

 Gyclotella operculata, which puts out its mycelial tube between the valve 

 and the girdle-band, thus penetrating into the cell. Another new species, 

 B. sphserotheca, attacks the microspores of Isoetes lacusiris, producing in 

 them a fatty degeneration. 



Mycorhiza.- -Herr B. Stein J confirms the observations of Frank on the 

 occurrence of a symbiotic fungus on the roots of trees, and enumerates a 

 large number of species in which he finds its presence to be constant. He 

 regards the fungus as playing a most important part in supplying nutriment 

 to the trees on which it grows. 



M. F. Kamienski § believes that true symbiosis of a fungus-mycelium 

 with a root is not so common a phenomenon as Frank supposes. In 

 the case of Carpinus Betulus he finds that the fungus which clothes the 

 roots has a distinctly prejudicial influence upon them, causing hypertrophy 

 of the tissue, and in that of Pinus sylvestris abnormal dichotomous branching 

 and resinosis in the vascular bundles of the roots. Monoiropa hypopitys, 

 on the contrary, furnishes an example of true mycorhiza, the fungus being 

 found on the surface of the root, not as a parasite, exercising no injurious 

 influence, and carrying nutriment to the root. 



* Verhandl. Zool.-bot. Gesell. Wien, xxxvii. (1887) pp. 39-40 (1 pi.). 



t Ber. Naturf. Gesell. Halle, 1886, pp. 31-7. Cf. this Journal, ante, p. 283. 



+ JB. Schles. Gesell. vateii. Cultur, Ixiii. (1880) pp. 409-12. Cf. this Journal, 1886, 

 p. 113. 



§ Arbeit. St. Petersburg Naturf. Gesell., xvii, (1886) pp. 34-6. See Bot. Centralbl., 

 XXX. (1887) p. 2. Cf. this Journal., 1886, p. 113. 



