250 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Pseudoéorter. A cortex devoid of cellular structure and commonly showing well 
defined or more or less gelatinized hyphx. (PI. 4, facing p. 67.) 
Pustule. A pimple-like or blister-like elevation. 
Pyrenocarpic. Same as angiocarpic. 
Rank. One of several series of podetia, produced successively by proliferations from 
one or more podetia of the next series below. 
Rhizoid. <A slender filament, consisting of a bundle of hyphe, extending downward 
from the lower side of the thallus and usually penetrating the substratum. (Fig. 
12, p. 156.) 
Rimose. Having chinks or cracks. 
Scyphiform. Cup-like, or forming a cup; said of some podetia, (PI. 17, facing p.125.) 
Sea-green. The peculiar greenish-gray which is the most common color of lichen thalli. 
Sessile. As applied to apothecia, meaning attached to the substratum by the central 
portion of the lower side. (Pl. 36, A, facing p. 194.) > 
Solexform. Slipper-shaped; said of certain spores. 
Soredium. A tangled mass of algal cells and fungal hyphe, which is able to grow into 
a new thallus under favorable circumstances of environment. (PI. 43, B, facing , 
p. 210.) 
Spermagonium. A minute cavity more or less embedded in the thallus and con- 
taining the spermatia borne upon sterigmata. (Fig. 4, p. 17.) 
Spermatium. One of the spore-like bodies contained in the spermagonia and sup- 
posed by some lichenists to be male reproductive bodies. (Fig. 4, p. 17.) 
Squamule. One of the small scales which compose certain lichen thalli. (PI. 15, 
facing p. 114.) 
Squamulose. Composed of squamules. 
Stipe. An apothecial stalk, devoid of algal cells. (Pl. 1, A, facing p. 48.) 
Symbiont. One of the individuals of a symbiosis, 
Symbiosis. A living together of two, or rarely more, dissimilar individuals with 
mutual benefit, or at least with benefit to one of the symbionts. 
Thalloid. Thallus-like. 
Thallus, The vegetative portion of any lichen, bearing the reproductive areas or 
organs, 
Theeial. Occurring within the thecium (or hymenium). (Fig. 6, p. 29.) 
Trichomatic. Trichome-like. 
Tubxform. Trumpet-shaped, said of certain podetia. 
Turbinate. Top-shaped. 
Umbilicus. The single strong attaching organ of some lichen thalli, composed of a 
large number of closely united hyphex. 
Uniseriate, Placed in a single row; applied to spore arrangement in the ascus. 
Ureeolate. Pitcher-shaped, or cup-shaped. 
Verruca. A wart-like elevation of a lichen thallus. 
Verrucose, Covered with verruce. 
