56 PALEOBOTANY [Box. Absts., Vol. IX, 



a single large cup, as in Peziza. It is among the lichen-forming Ascomycetes that the most 

 prominent suggestion of vestigial sexual organs occurs. Though curiously parallel, the 

 Florideae and the lichens have no direct connection. The higher algae present a firm cortical 

 layer resistant to intrusion and therefore the gonidia of lichens did not intrude during life 

 in the open sea but probably in pools. It may be suggested that fungal hyphae represent 

 the internal heterotropic portion of a seaweed with the cortical photosynthetic layers lost 

 because of lack of oxygen. The complex soma of higher fungi simply represents the "skinned" 

 soma of a complex alga, hence the striking similarities in reproduction. The algae of the 

 lichen gonidia have penetrated later into the denuded algal soma; in this connection the 

 attachment of unicellular algae to denuded seaweeds in pools is noted. The lack of sufficient 

 oxygen for respiration at night in pools probably led to the death of the cortical layer, and 

 probably to migration to subaerial ("splash") habitats. The first stage of migration to the 

 land is shown by seaweeds living above the surface, but within the region of "splash." Lack 

 of nitrogen and water keep the lichen thallus small after emergence. Resistance to drought 

 is not characteristic of lichens, occurring also in some algae and fungi. Lichens are probably 

 the oldest surviving race of land plants. It remains to show the course of evolution in the 

 reproductive processes. The lichens and fungi are evidently polyphyletic. — K. M. Wiegand. 



PALEOBOTANY AND EVOLUTIONARY HISTORY 



E. W. Beery, Editor 

 (See also in this issue Entries 332, 339, 373, 512) 



•> 



374. Arber, Agnes. Water plants: a study of aquatic angiosperms. xvi + 436 p 

 171 fig. Cambridge Univ. Press. 31s. 6d. 1920. — The book contains mucli of intert&t from the 

 standpoint of phylogeny and evolution. [See also Bot. Absts. 9, Entry 380.] — E. W. Berry. 



375. Berry, Edward W. A Potamogeton from the Upper Cretaceous. Amer. Jour. 

 Sci. 1: 420^423, Fig. 1-8. 1921. — A very characteristic Potamogeton, P. perryi, is described 

 from the Ripley formation, late Upper Cretaceous, of western Tennessee. — E. W. Berry. 



376. Carpentier, Alfred. Decouverte du genre Plinthiotheca Zeiller dans le West- 

 phalien du nord de la France. [Discovery of the genus Plinthiotheca Zeiller in the Westphalian 

 of northern France.] Compt. Rend. Acad. Sci. Paris 172: 814-815. 1921. — This form, described 

 originally from Heraclee, Asia Minor, is recorded from Pas-de-Calais. It is interpreted as 

 a microsporophyll, elliptical in form and about 11 X 21 mm, in size, with one surface covered 

 with microsporangia. It is considered to represent the microsporophyll of either Ldnop- 

 teris obliqua or N europteris gigantea. — E. W. Berry. 



377. Chudeau, R., etP. H. Fritel. Quelques bois silicifies du Sahara. [Several silici- 

 fied woods from the Sahara.] Bull. Soc. Geol. France 20: 202-207. Fig. 1. 1920.— The general 

 occurrence and varied age of sandstones with silicified wood throughout northern Africa 

 are discussed. Three specimens of wood from the Sahara sandstone are described which are 

 referred to the recently proposed form genus Mesemhryoxylon Seward, and are considered as 

 probably of Cretaceous age. — E. W. Berry. 



378. Coleman, A. P. Paleobotany and the earth's early history. Amer. Jour. Sci. 1: 

 315-319. 1921, — A criticism, from the standpoint of physical geology, of Knowlton's thesis 

 of uniform geologic climates under the influence of terrestrial heat. — E. W . Berry. 



379. Depape, G. Sur la presence du Juglans cinerea L. fossilis Bronn dans la fiore plai- 

 sancienne de Saint-Marcel-d' Ardeche. [On the presence of Juglans cinerea L. in the Plio- 

 cene of Saint-Marcel-d' Ardeche.] Compt. Rend. Acad. Sci. Paris 171: 865-866. 1920. 



