New or otherwise interesting Fresh-water Algae from North America
✍ Scribed by G. W. Prescott; Herman Silva; W. E. Wade
- Publisher
- Springer
- Year
- 1949
- Tongue
- English
- Weight
- 527 KB
- Volume
- 2
- Category
- Article
- ISSN
- 1573-5141
No coin nor oath required. For personal study only.
✦ Synopsis
While examining algal collections from various parts of eastern and southeastern United States and Canada the authors found a number of plants which are judged to be worthy of description as new species . Also included here are some emended descriptions, together with notes on new records for North America .
The authors wish to acknowledge with their thanks the help of Dr. E . N. TRANSEAU in the preparation of species descriptions, and the assistance of Dr. HANNAH CROASDALE in writing the Latin diagnoses. Acknowledgements are also due the Muellhaupt Fellowship and the research fund of the American Association for the Advancement of Science .
Chlorophyta
Volvocaceae
Gonium Mueller, 1773 (Char. emend.) PRESCOTT ( 1 ) The discovery of Gonium discoideum PRESCOTT (1942, p . 116) in Louisiana requires a revision of the genus diagnosis, especially in respect to cell shape and numbers of individuals within a colony . Pl. 2, Figs. 1,2 .
A free-swimming, plate-like semi-quadrangular colony of 4-32 ovate, ovoid, pyriform or bilobed cells, so arranged within a gelatinous envelope that a rectangle of 4-8 central cells is inclosed by a peripheral series of 12-24 individuals (in colonies of 16 cells or more) ; long axis of the central cells at right angles to the plane of the colony, but axis of peripheral cells radial to the center of the colony ; cells interconnected by fine protoplasmic processes ; individual envelopes adjoined by stout processes with those of neighboring cells so that oval or quadrangular interstices are formed in the colonial mucilage ; flagella 2, attached in the narrow anterior end just above 2 contractile vacuoles ; chloroplast a parietal cup with 1 or 2 pyrenoids ; pigment-spot usually large and conspicuous, lying laterally in the anterior end ; sexual reproduction by the division of the vegetative cells into 4-16-32 isogametes which fuse in pairs, the quadriflagellate zygote becoming a thick-walled resting spore .