Leavitt: observations on callymenia phyij-ophora. 295 



Chlorochytrium tnclusum. — A section cut in fresh material 

 August 12, 1902, showed a mature vegetative stage of this 

 parasite, Plate XLV., fig. 5. It corresponded very closely to 

 the parasite on Constantinca rosa marina found and described 

 by Mr. E. M. Freeman. Dimensions : 150 mic. x 75 mic. 



It was oval in form and was inclosed in a thick cell wall 

 which protruded beyond the epidermis of the host. The parasite 

 lay mainly in the epidermis scarcely extending into the cortex 

 of the host. Several distinct pyrenoids could be distinguished 

 in the bright green chlorophyll. 



Endophyte, genus unknown. — This parasite was to be found in 

 the great majority of the sections cut in the laminae. It occurs 

 but rarely on stipe or holdfast. It is usually distinctly vase 

 shaped with the interior of the vase toward the interior of the 

 lamina. It often lies entirely in the subepidermis and never 

 extends beyond the surface of the host. The larger ones extend 

 down into the outer cortex. Each is enclosed in a thick wall. 

 The contents are homogenous, granular and vary from an almost 

 colorless to a yellow green in color. Often what appears to be 

 a large oil drop lies in the base of the vase. The parasite con- 

 sists often of two and sometimes of three or four cells (Plate 

 XLV., fig. 6), one large cell in the base of the vase and one or 

 two in the narrow neck. The larger plants are often one celled, 

 Plate XLV., fig. 7, and the small ones are sometimes two. 



Dimensions: length 35 mic. to 140 mic. width 25 to 45 mic. 

 Plate XVL., fig. 8, shows diagramatically the relative positions 

 of the cystocarp and the two parasites Callithamnion and . 



Explanation of Plates. 



Plate XLIV. figures Callemenia fhyllofhora f. orbicularis as to 

 general habit and structure. Plate XLV. figures various parasites 

 upon the plant. 



Plate XLIV. 



1. A young plant about half natural size. 



2. Older plant with secondary lamina? rising from margin and 

 surface, about one half natural size. 



3. Mature plant consisting of series of four lamina?, about one 

 half natural size'. 



4. Joint holdfast of young and mature frond attached to clam shell, 

 about natural size. 



5. Side view holdfast, natural size. 



6. Sucker-like under surface of holdfast, natural size. 



