80 MINNESOTA BOTANICAL STUDIES. 



the plant had been overlooked as its dirty brown or gray color 

 and its low prostrate habit gave it the appearance of debris. 

 Very few plants were found. 



Description of plant. — Nitella batrachosperma is of a dirty 

 brownish-green color, very small, from 1.8 cm. to 3 cm. high. 

 Most of the plants examined were 2 cm. high. There are from 

 two to four main branches springing from the first node. The 

 branches measure .5 mm. in diameter and from 4-7 mm. to the 

 first whorl of leaves. This whorl of leaves consists of six to 

 eight sterile leaves, having two divisions. The first division or 

 main ray is from 55 to 67.5 mic. wide and 685.5 to 75° m ' c - 

 long. The leaflets are about the same length and are two- 

 celled, the basal cell being very long, the end cell short and 

 sharp-pointed. The lower sterile leaves are loose and spread- 

 ing and stand at nearly right angles to the main branch. At 

 the tip of the branch the leaves are thick and compressed, giving 

 a bushy-like appearance to the plant. At the apex both sterile 

 and fertile leaves have from two to three divisions. In a fertile 

 leaf, having three leaflets divided and three undivided, the main 

 ray is 50 mic. broad and 312 mic. long. In a sterile leaf 

 with three leaflets divided and three undivided the diameter 

 of the main ray is 62.5 mic/>and the length 312.5 mic. In a 

 sterile leaf having three divisions throughout, the diameter is 80 

 mic. and the length 250 mic, showing little difference in size 

 of fertile and sterile leaves. The fertile leaves are all borne at 

 the tip of the branch and but lew leaves at the tip are sterile. 



Rhizoids. — Rhizoids arise from the first and second nodes of 

 the plant. The rhizoids from the first node are much larger 

 than those from the second, being 125 mic. in diameter, while 

 those from the upper are about 62 mic. wide. The rhizoids 

 have long cells and abut upon one another in the characteristic 

 " stocking-foot" manner of the Characeae. 



Reproduction. — Nitella batrachosperma is monoecious. The 

 antheridia and oogonia are usually borne on the same leaf, 

 though not always. Many of the leaves bear only antheridia, 

 few bear only oogonia. The organs can be distinguished only 

 by careful examination as they are minute and the color, a 

 yellowish-brown, differs but little from the color of the plant. 



Anther idium. — The antheridia are borne terminally upon the 

 first segment of the leaf. The second and third divisions do 

 not bear antheridia or oogonia. The development of the an- 



