Observations on the Germination of Ferns. 337 



as I can ascertain, a single cellule, the inert body which was con- 

 tained in the sporule called into life. The sporule is therefore com- 

 posed of two parts, namely, the external integument and the inter- 

 nal cellule. The latter swelling beyond the capacity of the former 

 bursts it open, and is then elongated a little beyond the ruptured 

 edges of the integument. From the anterior apex of this primordial 

 cellule, another is emitted generally of a spheroidal form, and about 

 the same time an exceedingly minute pellucid fibril is emitted from 

 its posterior end. 



The first indication of the formation of a new cellule is the emis- 

 sion of a small ovate body from the anterior end of the previously 

 formed one : at first it is almost colourless, and appears like a mere 

 exudation of sap ; as it advances, its almost liquid surface is gradu- 

 ally changed into a greenish pellicle, and the cellule then swells in- 

 to a spheroidal form ; but this form is very soon altered, when in its 

 turn it has protruded a new cellule. This last, originating on the 

 convex apex of the preceding, (from which it appears to draw the li- 

 quid necessary to its own formation) is during its enlargement gra- 

 dually drawn closer and closer to the other, the convex end of which 

 finally becomes concave as the two surfaces approximate and form 

 the partition between one cellule and another. 



The manner in which the cellules increase varies in different spe- 

 cies. In some a single cellule is emitted from the primordial one, 

 and from the end of that another, and so on to the amount of four 

 or five before any lateral increase takes place. They then begin to 

 increase rapidly to the right and left, ultimately forming two round- 

 ish lobes, with a deep intermediate sinus. As the cellules are ad- 

 ded, delicate fibrils issue here and there from their lower surfaces, 

 at or near their union with one another, taking a downward direc- 

 tion, and finally insinuating themselves into the pores of the soil. 

 The lobes continue to increase externally until they have attained 

 a certain size, when all external increase ceases ; the primary frond* 

 is then composed of a single lamina of cellules, which diminish in 

 size from the centre to the circumference, and in appearance very 

 much resembles the thallus or lobed frond of some Hepaticae. 



But this is only one of the forms which the primary frond as- 

 sumes. Some increase more rapidly at first, and soon acquire a cir- 

 cular or reniform shape, increasing by the addition of cellules at the 

 circumference ; others divide into a number of lobes, standing nearly 

 upright; while some produce one lobe after another, the lobes being re- 



* This term is used because I can rind no one given by botanists applicable 

 to this state in ferns. 



