July 1907] Leaf-Tip Blight of Draccsna Fragrans. 139 



leaf inch by inch is a species of anthracnose of the genus Gloeos- 

 porium." 



Several anthracnoses were being studied when this one on 

 the dracaena was found. Pure cultures of it were obtained for 

 comparison with the others. Conidia began to develop in the 

 cultures when they were only a day old. These conidia were 

 borne on the ends of hyphae from the sides of the filaments of 

 the radiating mycelium. A little later, acervuli began to appear 

 in the cultures, the mature conidia collecting in little pinkish 

 masses on the surface of the culture medium. 



Developing along with, and for some time after, the acer- 

 vuli, were small black bodies resembling young acervuli ; these 

 bodies proved to be perithecia, containing long, slender para- 

 physes and club-shaped asci with hyaline, single-celled spores. 

 In size and general appearance, the conidia and ascospores were 

 alike except that most of the ascopores were slightly curved. 

 The perithecia varied from spherical to flask-shaped and long- 

 rostrate, the long-rostrate forms being for the most part deeper 

 in the culture medium. There was a tendency to produce only 

 the perithecial stage after the fungus had been grown for several 

 generations on artificial media. 



After perithecia were obtained in the cultures, the leaves 

 were examined and patches of perithecia were found on them. 

 Pure cultures were then obtained from some of these perithecia, 

 and both conidial and perithecial stages developed from the as- 

 cospores, proving that the acervuli and perithecia on the leaves 

 were stages of the same fungus. 



Inoculation experiments were now begun by inoculating 

 pieces of sterilized bean stems with conidia from the pure cul- 

 tures. In a few days acervuli began to show on the bean stems, 

 and later, perithecia. These perithecia were superficial, some- 

 what hairy and flask-shaped, while those on the dracsena leaves 

 were sub-epidermal and sub-spherical. 



Three plants of Dracaena fragrans were placed side by side 

 in the greenhouse. After waiting several weeks to see whether 

 they had the same disease, two of them were inoculatd with 

 conidia from a pure culture. Several of the leaves were killed 

 back from the tips from one to three inches and one had a spot 

 on it. Acervuli developed in all the dead areas and perithecia 

 in one. The fungus was transferred from the inoculated plants 

 to the third by spraying them with a hose. The fungus spread 

 very rapidly on the infected leaves when they were removed and 

 placed in a moist chamber, acervuli and perithecia developing 

 in abundance. 



I am in doubt about the taxonomy of this fungus. Dr. 

 Halsted^ called it a species of Gloeosporium, and so it seems to 



^T7 



