COCCOGONALES 



13 



Chamaesiphonaceae : Chamaesiphon (chamae, on the earth; 

 siphon, a small tube). Fig. 5. 



The cells are epiphytic, solitary, or arranged in dense clusters; 

 they stand erect, are more or less rigid, vary much in shape and are 

 attached at the base. The sheath is thin, hyaline and ultimately 

 opens at the apex. Reproduction is by means of gonidia which are 

 abstricted successively by transverse division from the apex, and as 

 these gonidia have been regarded as one-celled hormogones the genus 

 thus forms a link between the Coccogonales and Hormogonales. 





1.^^ 



^ 





m 



Fig. 5- 





m 



f»T 



Fig. 5. 

 Fig. 6. 

 Fig. 7- 



A B 



Fig. 6 A B 



Fig. 7. 

 Chamaesiphon cylindricus with gonidia ( x 1200). (After Geitler.) 

 Spirulina. A, S. major ( x 1070). B, S. subsalsa ( x 1070). (After Carter.) 

 Oscillatoria. A, O. formosa (X613). B, O. corallinae (X613). (After 

 Carter.) 



HORMOGONALES (REPRODUCTION BY HORMOGONES) 



OscjLLATORiACEAE : SphuUna {spirula, a small coil). Fig. 6. 



The trichomes have no proper sheath and are septate, although 

 the septa are frequently very obscure. The trichomes are simple, 

 free and coiled into a more or less characteristic spiral. 



*OsciLLATORiACEAE : OscUlatoria (oscillare, to swing). Figs, i, 7. 



The trichomes are free, smooth or constricted, straight or arcuate 

 and often form tangled masses, the sheaths being delicate or more 



