202 



THE AMERICAN MONTHLY 



[November, 



it differs from the thallus, and partakes 

 more of the color of the nucleus, it is 

 a proper excipulum. The hymenium, 

 or thalamium, is the centre of the 

 fruit organ, and is easily recognized 

 by its color and gelatinous appearance. 

 It embraces the paraphyses, asci 

 and spores.The paraphyses (6 Fig. 46) 

 are long, slender, cylindrical, hyaline, 

 cells, or filaments ; swollen at the 

 apices into the shape of a club, where 

 they are also frequently of a dark or 

 pale color. They grow upright or 

 vertical from a bed of cells, known as 

 the hypothecium, (4 Fig. 46), and 

 stand like corn in a field, only closer 

 together. Their apices are glued 

 into a solid mass, and form what is 

 called the epithecium, or disc of the 

 fruit. The direct function of the pa- 

 raphyses is not clearly understood ; 

 but it is, without doubt, to subserve 

 the spores. By their agglomeration, 

 they retain around the asci, if they do 

 not secrete it, a large quantity of 

 lichenine, which helps the nourish- 

 ment of the young sporidia. They also 

 hold up the asci in a vertical posi- 

 tion, when being full of spores, they 

 would otherwise fall down upon the 

 hypothecium ; and when the asci and 

 spores are ripe they act as a sort of 

 spring upon them, caused by the ex- 

 pansion and contraction of damp and 

 dry weather. The spores are thus, 

 by pressure, expelled into the air 

 through the disc or epithecium ; when 

 the wind wafts them on, to grow in 

 new spheres. The asci or thecse (5 

 Fig. 46), are large vesicles or sacs, 

 growing upright among the paraphy- 

 ses from the hypothecium. They are 

 in shape oblong, pyriform, linear or 

 clavate ; but always tapering off at 

 the base. They are closely pressed 

 by the paraphyses, from which they 

 differ by being broader and inferior 

 in length. The spores are formed and 

 matured in these sacs ; and when 

 ripe, by the lateral pressure of the 

 paraphyses, or the internal pressure 

 of the spores, or from both, the ascus 

 ruptures at the apex, and the spores, 

 are liberated The spores (Gr. spora^ 



a seed). Fig. 46, is the reproductive 

 germ. It is formed in the ascus from 

 a protoplasmic-lichenine matter. 

 When mature, it consists of a cell 

 having an inner and outer wall, ter- 

 med respectively, the endosporium and 

 episporium. It is frequently divided 

 by septa into two or more cells. The 

 spores are generally eight in number, 

 in each ascus ; but some of the larger 

 spored forms, as Fertusaria, produce 

 in the spore-sac four, two, and some- 

 times only one spore, while on the 

 other hand, in minute spored species, 

 they are innumerable. The form and 

 color of the spores are very much 

 disversified. They range from glo- 

 bose to fusiform and acicular. That 

 is, from round to spindle and needle- 

 shape. Their color is from a pale 

 greenish or yellowish tinge, to a dark 

 olive or deep brown. 



Composed of these several parts, 

 the apothecium constitutes the female 

 organ of the fructification, the spores 

 of which are fecundated by the mi- 

 nute bodies next to be described ; but 

 how, or in what way, this fecundation 

 is affected, has not yet been discove- 

 red. The fecundating bodies are 

 termed spermatia. They are very 

 minute rod-like, or oval organs, vary- 

 ing in length and breadth ; and are 

 sometimes bent or curved ; they are 

 uncolored and transparent. These or- 

 gans are produced in small cavities, 

 sunk or immersed in the Lichen-thal- 

 lus ; and opening on its surface by a 

 small pore. These cavities or cysts 

 are called spermogones. (Fig. 47). 



Fig. 47. 



