THE MYXOPHYCEiE OF LAHORE. 9 



SYSTEMATIC* Of the two orders of the Myxophycea, namely 

 the Coccogoneaz and the Hormogonece, the latter has been much more 

 studied by the writer. Amongst the former, Chroococcus turgidus 

 Kuetz, (Cooke, 7. c. p. 204, pi. 83, fig. 2) is very commonly found for 

 the most part of the year, generally sticking to the submerged walls 

 or the floating masses of decaying vegetable matter in stagnant ponds 

 or ditches. It is about 20/* thickness, and is often seen to be 

 dividing into two, or rarely into four. 



Gloeocapsa polydermatica Kuetz., is very common amongst the 

 grass on lawns after a little rain or watering. It forms a thick, 

 green layer when moist. Individual cells have a hyaline lamellose 

 membrane, and are about 5/u. thick. When dry, the stratum becomes 

 greenish- brown, the membrane of the individual cells also taking on 

 that colour. 



Clathrocystis aeruginosa Henf. (De Toni, I.e. p. 94: Cooke, I.e. p. 212 

 pi. 86, fig. 7) forms a bright green scum on stagnant water, generally 

 where the water is full of waste organic matter such as the Duck 

 Pond in the Zoo. Fronds of various sizes and of various shapes are 

 commonly met with at the same time. Young fronds seem to be solid, 

 but as they grow old they become hollow, and finally clathrate. 



Two or three species of Merismopedia are fairly common, with 

 their families freely floating in stagnant water, or sometimes sticking 

 to floating masses of decaying vegetable matter. 



Of the second orders Hormogoneai, the Cohort Psilonematea 

 is very well represented in Lahore, while the Cohort Trichophorea 

 is as yet found to be represented only by Eivularia bullata Berk. 

 Of the former, the three families, Oscillator iacece, Nostocacece and 

 ScytonemacecB have been found to be fairly well represented, while 

 no plant of the Stigonemacece has as yet been discovered. 



Oscillatoria princeps Vauch. (De Toni, /. c. p. 150) is the thickest 

 species of the genus yet found. It generally occurs in dirty drains, 

 carrying off water from road-side water-pipes. Stratum dark green, 

 first attached to the mud and then floating. Trichomes straight, 

 rigid, yellowish-green, about 36/* thick. See Fig. 1. 



Oscillatoria tenuis Ag. (De Toni, I. c. p. 166 ; Cooke, /. c. p. 249; 

 pi. 96, fig. 8) is the commonest Oscillatoria of Lahore, found general- 

 ly in dirty draius and in places constantly wetted, such as in mud 



* The classification of the Myxophycese followed in this paper is taken 

 from J. B. De Toni's ' Sylloge Algarum ', Vol. V., (1907). The species have 

 been identified from descriptions in that book or from descriptions and 

 figures given in M. C. Cooke's British Fresh-water Algae (1882— 1884). 

 Exact references are given after each species. 



461—2 



