Vol.1] Reed. — Two New Ascomycetous Fungi. 151 



THE PRASIOLA-COMPOSITE. 



The seeond algal-composite, when fresh and moist, is a dull 

 olive- green, bnt becomes brownish to leaden olive when dry. 

 The older plants are always the darker. 



The fronds are very much broader than long, much curled 

 and crinkled, and often the edges are involute until they meet, 

 so that each frond seems like a little sack. Each plant has three 

 or four fronds arising from a single very short stipe at the 

 center, or separate stipes from a small central hold-fast. The 

 plant is 2-4 em. across, while the fronds are from 2-4 cm. wide 

 and 1-2 cm. in length. (Cf. Fig. 7, PI. 15.) 



The fronds are soft, flabby, and easily torn when moist, but 

 become brittle and coriaceous or leathery when dried, especially 

 when old and covered with perithecia. The greater part of the 

 surface of the frond is roughened by the brownish hemispherical 

 elevations of various sizes, 180-454 ^ in diameter by 90-175 /* 

 high. They are scattered over both surfaces irregularly from 

 near the base to the apex of the frond. The cells viewed from 

 the surface are grouped in tetrads, much as in the ordinary 

 Prasiola, and the tetrads are arranged in quadrate or polyg- 

 onal areas, with distinct hyaline spaces between. In the young 

 fronds, having but little or no fungus in the tissues, the 

 tetrads are very regular and the interspaces perfectly hyaline, 

 (Cf. Fig. 13, PI. 16) but in older fronds, completely occupied by 

 the fungus, the interspaces are no longer hyaline but closely 

 packed with pigmented tips of the liyphap. These tips stand up 

 perpendicular to the surface like pile on velvet, and are sometimes 

 between the cells forming the tetrads, as well as the areas between 

 the tetrads. It is these tips which darken the fronds and increase 

 their thickness and toughness. The surface measure of the cells 

 varies from 4 to 10 /^ in different fronds. 



In the cross section the outermost gelatinous layer of the 

 frond sometimes shows a slight stratification, especially in the 

 old plants having many perithecia. The outer layer is also denser 

 and the hyphee do not penetrate through it to its surface. 

 Beneath this layer the hyphfP are abundant and evenly dis- 

 tributed in the older specimens, but very much more scattered 



