of Fructification in Peyssonnelia Squamaria. 157 



apparently dichotomous, but in reality simple, with long endo- 

 chromes, performing probably the office of paraphyses ; the others 

 of the same length, but far larger ; and it is remarkable that it is 

 the endochromes of these which become spores absolutely in the 

 same way as in a great number of conceptacula of Floridece, as 

 for instance in Nothogenia variolosa^ Melanthalia Jaubertiana, 

 Plocaria confervoides, Sphcerococcus coi'onopifolius, Delesseria hy- 

 poglosson, &c. (see the analyses given by myself and Kiitzing). 

 Thus we find rows of two, four, six or even eight spores, accord- 

 ing to the degree of evolution at which the nemathecia have ar- 

 rived. It appears that their development proceeds from the 

 upper part of the thread, taking a downward course, because 

 those which are nearest the upper surface of the nemathecia are 

 the largest and most spherical, the lower ones being still elon- 

 gated and clavseform, and much more slender. This however 

 may depend on the form of the nemathecia whose convexity 

 allows a greater extension than the base. The number of the 

 spore-producing threads is large enough to make one imagine 

 that the nemathecia are entirely composed of them, but in com- 

 pressing them under Shiek^s compressorium, threads are distinctly 

 observed remaining still in the form of paraphyses. When the 

 row consists of four spores only, it might be taken for a linear 

 tetraspore. Nevertheless there is even then this difference, that 

 in this case the extreme spores are neither similar nor equal to 

 one another. The upper one is yg^jths of a millimetre in length, 

 and rather more than y§^ths in breadth, rounded above and 

 truncate below ; the second and third are truncate at either end. 

 The form of the lower was described before ; its length is y^^ths 

 of a millimetre, and its greatest thickness yg^ths. Observe, I am 

 describing here only a single series of spores, for they are very 

 variable according to the number of the spores of which they con- 

 sist. I should add, that when they are once free they are soon 

 clothed with a distinct perisporium and acquire larger dimensions. 

 Hence I have measured some, which, together with their peri- 

 spore, had a diameter of ^^^th of a millimetre. 



On the whole then, this form of fructification appears to me to 

 correspond with that which one meets with in the conceptacula 

 of Sph(2rococcoide(B and Delesserice. It differs simply in the ab- 

 sence of a conceptaculum properly so called, which is here re- 

 placed by filaments radiating from the surface which give rise to 

 the nemathecia. 



Nemathecia then may inclose three forms of fructification : 

 I. masses of spores inclosed in a pericarp [Favellidia, J. Ag.) as 

 in Polyides, and perhaps in Rhizophyllis (see Fl. Alg. 1. 16. fig. c 

 and c?) ; 2. tetraspores which may, as we see in the genus Fauchea 

 (I. c, 1. 16. fig. 1 A), and in Peyssonnelia, grow between the radia- 



