28 Thitry-foujrth Annual Report of the 



to suppose that if every cultivator of corn would go through his fields 

 at the proper time, that is, as soon as the excrescences have made their 

 appearance, and cut off and burn up every excrescence, he would 

 thereby prevent the dissemination of millions of these fungus spores 

 and do much toward the prevention of the continuance and spread of 

 the evil. Though the winds may carry the spores to great distances it' 

 is probable that most of them fall to the ground in the field in which 

 they are produced. In this event it is easy to see that corn raised for 

 several consecutive years on the same piece of ground would be more 

 likely to be affected with smut than corn raised where there is a con- 

 stant rotation of crops. 



The specific name Maydis, applied to this fungus, is derived from the 

 specific name Mays, which belongs to its supporting plants. Ustilago 

 Ze(B, Schw., is a synonym, the specific part of which is derived from 

 Zea, the generic name of Indian corn. The specific names of fungi 

 are often derived from the name of the plant they inhabit. 



Helminthosporium inconspicuum, G. & E. Obscure corn-leaf Fun- 

 gus. (Plate 3, figs- 4-6.) If the lower leaves of corn stalks be ex- 

 amined toward the end of Summer, some of them will be found to be 

 dead and discolored at and near the pointed end. This discoloration 

 is sometimes continuous, involving the whole outer half of the leaf, 

 and sometimes it is interrupted and forms spots of various sizes and 

 shapes. The spots, by increasing in size, become confluent, and thus 

 a leaf at first spotted may soon become uniformly discolored. The 

 discoloration results from the death of the leaf tissues and the destruc- 

 tion of the green coloring matter of the leaf cells, the affected part ap- 

 pearing to the observer like so much dead leaf. The fungus that 

 causes the discoloration is too minute to be easily seen by the unaided 

 eye. But if a hand-glass of moderate magnifying power is brought 

 into use, the surface of the dead spots will appear as if adorned with 

 a slight pubescence or hairiness. With good eyes, well trained, this 

 apparent hairiness can be seen in a favorable light by looking horizon- 

 tally across the surface of the affected part. By microscopic exam- 

 ination it is found that this appearance is not due to the presence of 

 hairs, but of a minute fungus. Numerous short, stiff, dark-colored 

 articulated threads grow up from the surface, each one of which bears 

 at its apex one or two nearly black spores. These are about as long 

 as the threads and a little thicker. They are generally from thirty- 

 five to forty-five ten-thousandths of an inch long, and about one- 

 seventh or one-eighth as broad. They are divided into several cells by 

 dark transverse partitions. In the original description of the species 

 these partitions are said to vary in number from three to five, but I 

 have generally found them more numerous, running up even to eight 

 or nine. The life history of this fungus has not yet been traced and 

 therefore it is not known where it passes the Winter. The genus to 

 which it belongs takes its name from two Greek words, one of which 

 signifies a worm, and the other, a spore. It was doubtless given be- 

 cause of some fancied or real resemblance between the spores of some 

 species and a worm. The species of Helminthosporium usually in- 

 habit vegetable matter already dead. From the habit the present 

 species has of attacking the lower leaves only, which already have had 

 their vigor impaired by age, and their vitality diminished by partial 



