MYCOLOGICAL SECTION. 137 



EXPLANATION TO PLATE IV. 



THE ANTHRACNOSE OF THE GRAPE (SPHACELOMA AMPELINUM, DE BARY). 



Fia. 1. A bunch of Elvira grapes partially destroyed by anthracnose. Received 

 from G. Wanner, Wallialla, S. C, June, 1886. 



Fig. 2. Vertical section (enlarged) of diseased berry, showing epidermis and sub- 

 epidermal tissue. The basidia develop large numbers of spores (conidia), 

 v/hich lie immediately beneath the epidermis, a, and finally rupture the 

 latter and escape, b. 



Fig. 3. Section similar to b of Fig. 3, but more enlarged. Here we have a mass of 

 basidia differentiated into spores, and resting upon a bright-colored 

 stroma, b, beneath which e is a dark layer of diseased tissues, which gi-ad- 

 ually passes into the deeper sound tissue, d. The ruptured epidermis is 

 seen at a. 



Fig. 4. Mature spores, much magnified. These are usually thin walled and trans- 

 l^arent, with one or more bright spots. 



Fig. 5. Same as Fig. 4, but germinating. This fungus probably exists in other forms, 

 yet unknown. De Bary ha^ found spermagonia associated with Sphace- 

 loma, but has not been able to determine whether they belong to it. 



EXPLANATION TO PLATE V. 



CONHDIA, CONIDIOPHORES, AND INTERNAL MYCELIUM OF CERCOSPORA APII, FRIES. 



Fig. 1. The usual appearance of a leaflet of celery when attacked by blight. 



Fig. 2. A much-magnified transverse section of leaflet, showing myceUum travers- 

 ing the loose tissue to pass through a stoma on the lower surface and de- 

 velop hnear, clavate, septate, colorless conidia. 



Fig. 3. A group of conidiophores pushing out of a stoma, as in Fig. 2, but more en- 

 larged ; conidia attached and separated. 



Fig. 4. Another and older group of iionidiophores with conidia. 



Fig. 5. Germinating conidia. 



Fig. 6. Internal, transparent, branching, septate mycelium. 



Fig. 7. A new growth from a conidiophore (two months dry in herbarium) after 

 soaking twelve hours in water. The infected leaves were brought in from 

 the market in October, and this drawing was made in December. 



EXPLANATION TO PLATE VI. 



THE ORANGE-LEAF SCAB — CLADOSPORIUM SP. 



Fig. 1. Diseased leaves and twig. Received from Ocala, Fla., June, 188G. 



Fig. 2. Small portion of a leaf, considerably magnified to show the wart-like ex- 

 crescences in various stages of growth. 



FlQ. 3. A vertical section through one of the older excrescences, showing stroma, 

 conidiophores, and conidia— of the fungus growing upon it. 



EXPLANATION TO PLATE VII. 



CONIDIOPHORES AND CONIDIA OF PHYTOPHTHORA INFESTANS, DE BART. 



Fig. 1. A luxuriant liypha filled with granular protoplasm, and bearing four imma- 

 ture conidia. The entire hypha, a considerable portion of which is not 

 here represented, consisted of a single cell. Camera sketch, February 5, 

 1886. The specimen was grown from sowings of conidia made in moist 

 air one week previous on the cut surface of a sound potato. At a later 

 stage of gi-owth the conidia are partitioned off by cross- walls, and tlie 

 protoplasm largely disappears from tlie branches. In old conidiophores, 

 at irregular intervals a^few cross-walls are occasionally to be found. No 

 septa were observed in the internal mycelium. 



Fig. 2, A conidiophore with mature conidia in place. The spores fall off easily 

 when mature, especiallv if in contact with water. This conidiophore grew 

 from a solid white portion which was cut from the interior of a diseased 

 tuber (one somewhat brown-spotted only), and placed in moist air, the 

 mycelium having been previously detected in this part of the tuber. Tlie 

 figure shows the characteristic fiask-shaped swellings of the conidiophores 

 and the manner of attaclmieut of the conidia. The specimen was exam- 

 ined dry, with a low power. The figure has been enlarged from a camera 

 sketch, December 16, 1885. 



