10 THE JOURNAL OF INDIAN BOTANY. 



round water-pipes or wells. Stratum thin, bright green. Trichomes 

 radiating and actively oscillating, 4-8/* thick, generally a little 

 constricted at the joints. Two varieties occur in Lahore, one with 

 straight broad apex, and the other with curved and *a little attenu- 

 ated apex. 



Osciliatoria terebriformis Gom. (De Toni, I. c. p. 189) is general- 

 ly found forming a green scum on stagnant ponds, associated with 

 Clathrocystis csruginosa and Arthrospira Tenneri Kuetz. Trichomes 

 free swimming, flexible, screw-shaped or in lax spiral, with uncon- 

 stricted and indistinct joints, 4-6/x thick ; apex generally drawn out. 



The Sub-family Spirulinecs is represented by Arthrospira Jenneri 

 Kuetz. (De Toni, I. c. p. 206; Cooke, p. 245, pi. 96, fig. l) 

 which, as mentioned above, is generally found associated with Clath- 

 rocystis csruginosa and Osciliatoria terebriformis. Trichomes bright 

 green, elongated, 4-6/* thick. Spirals 10-16/* in diameter, and 

 about 8/* distant. Joints distinctly constricted ; cells globose. 



Of the Sub-family Lyngbyecs, Phormidium is more frequent than 

 Lyngbya. Phormidium ladinianum Gom. (De Toni, l.c. p. 218) has been 

 found on tree trunks, especially on that of Acacia modesta, associated 

 with Phormidium Hansgirgi Schm. and Tolypothrix byssoidea Kirchn i 

 Stratum dark green, thin, fibrous. Trichomes straight, flexible, 

 constricted at the joints, 4-6/* thick. Sheath thin, hyaline. Con- 

 tents granulose, sometimes hyaline in the centre. See Fig. 3. 



Phormidium tenue Gom. (De Toni, I. c. p. 227) generally sticks to 

 the submerged walls of artificial tanks, forming a membranous, expand- 

 ed, dirty green stratum on the mud. Trichomes long, a little curved 

 and densely intricate, slightly constricted at the joints, 1-2/* thick. 



Phormidium Hansgirgi Schm. (De Toni, I. c. p. 235) is found on 

 tree trunks, associated with Tolypothrix byssoidea and Phormi- 

 dium ladinianum, forming a dark bluish-green stratum. Trichomes 

 parallel, 10-12/* thick, with broad convex apex. Sheath hyaline 

 when moist, and dirty brown and fragile when dry. See Fig. 4. 



Phormidium .Moerlianum Grun. (De Toni, I. c. p. 236) is found in 

 stagnant water, where decaying vegetable matter is present. It is 

 generally associated with a species of Oedogonium. Trichomes long, 

 a little curved, brownish, 9-12/* thick ; joints very short. Sheath 

 thin, colourless. Dissepiments granulated. See Fig. 5. 



Lyngbya aestuarii Lieb. (De Toni, I. c. p. 262 ; Cooke, I. c. p. 258 

 pi. 101 fig. l) is commonly met with, associated with a species of 

 Oedogonium, and forming freely floating greenish masses. Trichomes 

 long, flexuous, blue-green, granular, about 40/* thick; joints very 

 short. Sheath hyaline, clearly lamellose and brownish when old. 



