PLATE V. 



Fig. 

 1. — Section of a spermogone of A. oxysporus. 



a. Cortical tissue of deformed portion of thallus of P. saxatilis on 



which the plant is parasitic. 



b. Gonidic tissue of same. 



c. Medullary tissue of same. 



fd. Envelope of spermogone formed of a brownish cellular tissue. 

 . Sterigmata forming the inner walls of the spermogone, and gene- 

 rating the spermatia from their apices. 

 /. Free spermatia escaping by spermogonal ostiole. 

 2. — Sterigmata and spermatia more highly magnified. 



a. Sterigmata. 



b. Spermatia. 



3. — Section of a spermogone of P. saxatilis. Its structure is similar to 

 that of A. oxysporus ; but the sterigmata are seen to be articulated, 

 the spermatia to be generated from both sides and apices, and the 

 interior of the spermogone to be occupied by a loose network of 

 very delicate, ramose filaments, which spring, along with the sterig- 

 mata, from the inner walls of the spermogone. 



4. — Portion of the tissues forming the spermogonal walls, more highly 

 magnified. 



a. Component cells of the brown envelope. 



b. Articulated sterigmata. 



c. Spermatia, which arise generally at an angle from the apices of the 



constituent joints or articulations of the sterigmata. 



d. The ramose delicate filaments, whose anastomoses and intertwinings 



constitute the network of the spermogonal cavity. Some of them 

 appear septate or articulated at the apex, where also they are 

 generally granular and dark. 

 5. — Section of one of the pycnides of A. Smithii. 



a. Cortical layer of matrix (deformed thallus of P. saxatilis). 



b. Gonidic layer of the same. 



e. Medullary tissue of the same. 



d. Brownish cellular envelope. 



e. Sterigmata close-set, short, delicate, forming the inner wall of the 



pycnidis, each bearing at its apex a stylospore. 



f. Free stylospores escaping by the ostiole. 



6. — Stylospores in different states and stages of development. Many of 

 them are seen to contain large or small oil globules, or to be filled 

 with an oily protoplasm. 



a. Mature stylospores. The colourless transparent specimens are full 

 of a homogeneous, oily, liquid protoplasm. 



b. The same, from some Highland localities. The oil globules have 



here a yellowish tinge. 



c. Shows the effects of pressure or reagents in rendering more evident 



the oily nature of the protoplasm. The oil globules are seen 

 escaping from the ruptui'ed stylospores, and many of them are 

 floating free. 



d. Stylospores of large size and irregular form from various Highland 



