164 Physiologie. — Palaeontologie. 



* 



nebst Notiz über die Zweikernigkeit ihres Karpogons. 

 (Ber. Deutsch. Bot. Ges. XXXV. p. 212-224. 1917.) 



Das Material stammte von Rovigno am Adriatischen Meere. 

 Diese Floridee gehört zur Gruppe der Nemalieae der Helminthocla- 

 diaceen] sie ist monözisch und haplobiont, d. h. Tetradensporen- 

 bildung fehlt. Am Ende des Fadens bilden sich plasmareiche 

 Monosporen, neben ihnen wird oft ein Haar ausgebildet. Es hatte 

 den Anschein, als ob manchmal 2 Sporangien nacheinander gebil- 

 det wurden, doch ist das nicht sicher. Die Monosporen ähneln den 

 Karposporen : sie besitzen auch amöboide Bewegung. Bei der Kei- 

 mung wird ein kriechender Faden gebildet; die Spore selbst bleibt 

 leer und ungeteilt und geht nicht in das Gewebe über. 



Das Karpogon ist zum mindesten während einer kurzen Ent- 

 wicklungphase 2kernig, in Gegensatz zu den bisher an dieser 

 Floridee gemachten Beobachtungen; doch konnte das Eintreten 

 des zweiten Kernes in die Trichogyne nicht nachgewiesen werden. 



Rippel (Breslau). 



Davis, C. A., On the fossil Algae of the petroleu m-yiel- 

 ding shales of the Green River formation of Colorado 

 and Utah. (Proceed. Nat. Ac. Sc. II. p. 114—119. 1916.) 



In the region extending from northwestern Colorado west 

 into Utah and north into Wyoming, there are great areas of, 

 generally, carbonaceous shales, which, in places, exceed 3000 feet 

 in thickness. They yield petroleum when subjected to destructive 

 distillation in closed retorts. Some beds are so highly carbonaceous 

 that they closely resemble compact lignite in appearance and burn 

 readily when heated. They belong to the Green River Formation of 

 Eocene time. 



Samples from near De Beque, Colorado, and, later, from 

 other localities, were submitted to the writer for microscopic exa- 

 mination. The rock is composed of organic residues and it was 

 found possible to soften the material without any visible change in 

 its original form or structure. After it was imbedded in paraffin, 

 sections could be made from it with razor or microtome. 



The ground mass of the sections was found to be ofthenature 

 of a somewhat granulär, organic jelly, closely resembling in optical 

 properties, some of the structureless, colloidal or sapropelic peats, 

 solidified and compacted into a dense, tough, impermeable magma. 



The ground mass, magma, or body of the shales, seems to 

 have been original!}^ vegetable matter. Imbedded in this magma 

 are innumerable plant cells. structures, and entire plants, which 

 are perfectly preserved. Many of these fossils are spores, fungi or 

 structures belonging to the higher plants but a large percentage 

 of them are clearly Algae of low tj^^pes. Three distinct types of 

 Algae have been discovered by the work so far done. 1) A very 

 considerable number of cellular, filamentous and gelatinous forms 

 which are clearly to be placed with the Blue-Green Algae. A mi- 

 nute, characteristic blue green Alga has been found that can almost 

 certainly be referred to the living genus Spinilina. 2) Somewhat 

 less common forms can be referred with more or less certainty to 

 the Green Algae. One resembles a species of Pediastrum in all 

 essentials. A type has been noted with Spiral chloroplasts, like 

 Spirogyra. 3) Unclassified Algae. These appear to be Algae but, as 

 yet, canhot be classified among known living Algae. Among these 



