MICROTHAMNION 191 
I. MICROTHAMNION KUETZINGIANUM Nageli; Kütz. Spec. Alg. 
352. 1849; Tab. Phyc. 3: f/. r. 1853. DeToni, Syll. Ale 1: 
256. 1889. Kirchn. Mik. Pflanz. M. r. f. ro. 189r. De 
Wild. Flor. Ale Belg. 38. کر‎ 73. 1896. (?) Schmidle, 
Hedwigia, 38: 169. Pl. 7. f. 13-15. 1899. Chodat, Beitr. 
Krypt. Flor. Schweiz. 1°: 288. f. 202, 203. 1902. (?) 
Scarcely Wolle, F. W. Ale M. 105. f. 1-4. 1887. 
Mature plants 60-200 ۸ tall, very densely and irregularly 
ramifications ; branchlets one- to several-celled, divergent, some- 
times curved, not narrowed at the ends ; cells cylindrical or some- 
times subclavate, 3-4 # in diameter, 2-4 (rarely 5-8) times as 
ong; chromatophore bright green, covering nearly all the outer 
cell-wall (ai 26, f. T; pl. 27, f. 2-4). 
Exsic.: Phyc. Bat. Am. 568. Greenhouse, Cambridge, 
Mass, 1899. (F. S. Collins). 
Plants solitary or more often forming a thin bushy coating on 
small dead stems, etc. In watering troughs, in rivulets, and on 
dripping rocks. 
CONNECTICUT : Watertown, May, (561B). 
New York: Morningside Park, March to June (322, 352, 
424, 532). 
Chodat’s description of the chromatophore as covering only two 
thirds of the circumference of the cell wall, as well as the open char- 
acter of the branching in his figures do not agree with what is here 
(and by Schmidle also) considered the typical form of this species. 
N 
. MICROTHAMNION STRICTISSIMUM Rabenh. Alg. Sachs. $29. 
1859; Krypt. Flor. Sachs. 1: 236 (fig.), 266. 18635; Flor. 
Eur. Alg. 3: 375. 1868. Schmidle, Hedwigia, 38: 169. ۰ 
7. f. 4, 5. 1899 | 
Microthamnion Kuetzingianum strictissimum Hansg. Prod. Alg. 
Bohm. 1: 91, 1886. DeToni, Syll. Ale 1: 258. 1889. Cho- 
dat, Beitr. Krypt. Flor. Schweiz, 1?: 288. 1902. 
Mature plants 300-600 £ tall, erect, branches generally alter- . 
nate, the main trunks distinguishable even to the summit ; branch- 
lets erect or ascending, obtuse and not narrowed at the apex ; cells 
cylindrical, 2.5—4 م‎ in diameter, 3-12 or even 15-20 times as long ; 
chromatophore thin, pale green, not always encircling the cell 
( سے‎ 
pl. 26, f. 2 
