OSCILLATOEIACEjE. 
109 
which the full grown frond assumes. The species are found either in the sea or in fresh 
or brackish water, and even on damp soil. A terrestrial species is common in Europe 
by the borders of clayey highways and paths, and may also be found in America. 
1. Microcoleus corymbosus , Harv.; fronds erect, rigid, tufted, multifid, the branches 
erect, level-topped, linear-clavate, closed at the extremity ; filaments densely packed, 
not oscillating. (Tab. XLYIII. B.) 
Hab. On mud-flats, near high-water mark, at Key West, mixed with Calothrix dura. 
W.H.H. (v. v.) 
Fronds half sunk in the mud, erect, tufted, from an eighth to a quarter of an inch in 
length, flexuous, tapering much to the base, gradually increasing in diameter upwards 
and dividing above into three or four or more erect branches, the lowest of which are 
longest, the upper gradually shorter, so that the apices of all are nearly on a level. 
These apices are obtuse, and closed. The investing sheath is tough and firmly mem- 
branous, and the enclosed filaments strongly cohere together, and are with difficulty 
separated. The colour of the sheath is ochraceous yellow, and of the endochrome dull green. 
The substance is very firm and rigid, and in drying the plant does not adhere to paper. 
Plate XLYIII. B. Fig. 1 . Tufts of Microcoleus corymbosus , the natural size. 
Fig. 2. Magnified view of two fronds. Fig. 3 . Portions of the enclosed filaments, more 
highly magnified. 
YII. EIYULAEIA, Both. 
Frond globose or lobed, fleshy, firm, composed of continuous radiating filaments, 
annulated within ; each springing from a spherical globule. (In the sea or in fresh 
water.) 
A fresh water species resembling the British B. pisum has been . sent to me by Mr- 
Eavenel from the Santee Canal, where it grows on submerged leaves and stems of plants. 
It is hemispherical, very convex, dark blackish-green and soft, and consists of densely 
set, spuriously branching, slender filaments. The specimens are not in a very perfect 
state, and I cannot say to which, if any, of the modern species they would belong. In 
old times they would pass for B. pisum , but it is nearly impossible at present to say 
exactly what that species is. 
