70 



THE AMERICAN MONTHLY 



[April, 



Family I. Palmellace^e Kirchner. 



Cells single, free or united by a gel- 

 atinous envelope, connecting stems, 

 etc., into large or small, mostly slimy 

 or gelatinous, families. 



Reproduction by vegetative cell- 

 division and formation of zoogonidia. 

 Copulation of zoogonidia has not been 

 observed in this family. 



a. Single cells, separate, or not 

 forming definite families. (Sepa- 

 rate. 



Synopsis of Genera. 



Cells single, spherical, floating ; en- 

 velope thick. JBremosphera^ i. 

 Cells separate in small, indefinite 

 families ; envelope thin. 



Pleurococcus.1 2. 

 Cells oblong ; floating, or attached by 

 hyaline pedicel. Dactylococcus^i 3. 

 Cells oblong, single or in rovv^s. 



Stichococcus^i 4. 

 Cells cylindric, straight or curved ; in 

 series end to end or bundles. 



Raphidium., 5. 



b. Cells united in families by the 

 envelope of the mother-cell enclosing 

 the daughter-cells. (Incluse;.) 



Synopsis of Genera. 



Cells distributed in large, gelatinous, 

 spherical families. Botrydina., 6. 



Cells oval ; in botryoidal, lobed fam- 

 ilies. Botryococcus.1 7. 



Cells enclosed in globose, lamellose 

 envelopes. Gloeocystis^ 8. 



Cells red, on thick gelatinous stalks 

 of concentric lamellose sti'ucture. 

 Urococcus., 9. 



Cells kidney-shape, lying separate in 

 ample, gelatinous envelope. 



Nephrocytium^ 10. 



Cells oblong, in common gelatinous 

 envelope. Oocystis., 11. 



Cells oval, "with large, colorless vac- 

 uole ; in common, gelatinous en- 

 velope. Glceococcus., 12. 



c. Cells united in families of char- 

 acteristic form by the formation of 

 slimy and confluent envelopes. (Gel- 



ATINOSE.) 



Synopsis of Genera. 



Cells oval, in tubular, branched, gela- 

 tinous thallus. Hydrurus. 13. 

 Thallus globose, eight-celled, float- 

 ing. Chroniophyton.1 14. 

 Cells in hyaline, cylindrical, single or 

 radiately arranged envelopes. 



Palmodactylon., 15. 

 Cells longitudinally arranged in tubu- 

 lar hyaline thallus. 



Hormospora^ 16. 

 Cells in hyaline envelopes, the latter 

 joined into a long thallus. 



Palmodictyon., 17. 

 Cells distributed in a hyaline thallus 

 attached by a pedicel-like base. 



Apiocystis, 18. 

 Cells in oval transparent envelopes in 

 a globose, hyaline thallus. 



Entophysalis., 19. 

 Cells distributed, often in twos and 

 fours, in a gelatinous layer. 



Tetraspora., 30. 

 Cells cubical, angular, in tubular fam- 

 ilies. Staurogenia^ 21. 

 Cells oval, in longitudinal series in 

 gelatinous thallus. Inodei'ma, 22. 

 Cells in gelatinous families, integu- 

 ments splitting in halves and quar- 

 ters remaining in the gelatin. 



Sckizochlamys ., 23. 



Cells green, red, or orange, thick 



Vi^alls ; indefinite gelatinous thallus. 



Palmella., 24. 



Cells spherical or angular, red or 



purple, in layer of gelatin. 



Porphrydium., 25. 



d. The single cells are united in 

 families by the formation of pedicels 

 or fine stems. (Stipitate.) 



Synopsis of Genera. 



Cells elliptic, on ends and at axes of 

 dichotomous, hyaline stems. 



Cosmocladititn. 26. 

 Cells terminal, on stems. 



Afisckococcus, 27. 

 Cells terminal, on very delicate stems, 

 in spherical hyaline thallus. 



Dictyosphcerium., 28. 

 Cells in fours, on very short branch- 

 ing stems. Dimorphococcus., 29. 

 Cells on radiating gelatinous stems 



