No. 1, August, 1920] MORPHOLOGY AND TAXONOMY, ALGAE 81 



60S. Meister, Kit. Zur Pflanzengeographie der schweizeriscben Bacillariaceen. [On the 

 plant geography of the Swiss Bacillariaceae.) Bot. Jahrb. 55 (Beiheft): 125 L59. 8 fig. L919. 

 — Brun in 1880 described 32 genera and 182 species from Switzerland; Meister in 1912 listed 

 45 genera and 376 species, or including varieties 621 forms. The greater proporl ion of I be Swiss 

 diatoms occurred also in the Tertiary. About one-half of the Tertiary diatomaceous flora 

 has persisted down to the present: thus when compared with the Phanerogams the conserva- 

 tive nature of the diatoms is apparent. The number that have appeared since Tertiary times 

 is less than those that have perished so that the diatoms seem to be a waning group. Tertiary 

 species common to central France and Hungary must have arisen in pretertiary times, there- 

 fore in the Cretaceous or Jurassic. The oldest known genera of fresh water Bacillariaceae are 

 Epithemia, Rhopalodia, and Melosira. The Swiss diatom flora shows a much closer relation 

 to the west European than to the east European tertiary flora. Several old tertiary forms 

 are now found living only in Switzerland. The oldest forms from the Oligocene or those of 

 the Miocene of west or east Europe now inhabit the bottoms of the Swiss lakes. There are 

 many diatoms in the Alps and in the colder lakes of the lowlands that occur elsewhere only 

 in the far north or in central Asia. Meister believes that Diatoms have migrated from cen- 

 tral Asia to the Alps and the Arctic region rather than the reverse. Why are there so many 

 endemic species in Switzerland when diatoms are generally so ubiquitous? There is no good 

 explanation at present, but the author assumes as a working hypothesis that the relics have 

 descended from preglacial times and that conditions during or before the glacial period were 

 different from what is generally believed. Meister shows that many diatoms inhabit both 

 highland and lowland lakes and are therefore not sensitive to variations in warmth; more 

 than three-fourths were found to be indifferent. Extensive lists are given in various portions 

 of the paper. Navicula acuta n. sp. is described. — K. M. Wicgand. 



609. Pilger, R. Ueber Corallinaceae von Annobon. [On the Corallinaceae of Annobon.] 

 Bot. Jahrb. 55: 401-435. 55 fig. 1919. — This paper is the first report on the algae collected 

 in 1911 by Dr. J. Mildbraed on Annobon, the smallest of the Guinea Islands, where the black 

 calcareous rocks support a rich flora of marine algae. These lime-loving algae inhabit a zone 

 between low and high tides which is wider on the west coast where the waves are high, and 

 narrowest on the north where there is simply the swell of the ocean. The Corallinaceae are 

 often very delicately colored. The decalcified material was imbedded in paraffin, sectioned 

 and stained with Ruthenian red, Bismark brown, chlor-iodide of zinc, or haematoxylin. A 

 brief account of the genus Goniolithon Foslie is given together with Foslie's diagnosis of the 

 genus, and Harvey's description of G. mamillare (Harvey) Fosl., the only species found by 

 Mildbraed. This species ranges from Brazil and Terra del Fuego to Cape Verde and Algoa 

 Bay. Foslie suggests that G. mamillare may be a juvenile form of G. brassica-florida. Pilger 

 gives extended descriptions of his material under four headings: (1) female material, (2) 

 tetraspore material, (3) inner structure of the conceptacle projections and the branches, and 

 (4) structure of the cortex. The female material formed thin crusts on the rocks with a 

 smooth or uneven surface, the crusts sometimes being proliferous. The tetrasporic material 

 produced crusts on stones or mussels. The cell structure, cell division, plasma membrane, and 

 chromatophores are described, and illustrated. The reaction of the different cells to chlor- 

 iodide of zinc is discussed. Elongation of the cell-rows takes place always by the division 

 of the uppermost cell of the row, and the cells are connected in the direction of growth by pe- 

 culiar double-faced pits. Heterocysts are formed in Goniolithon in 2's or 3's on the surf t n e 

 of the "Vorsprung." The whole floor of the tetrasporic conceptacle is covered with 4-par i 1 

 tetrasporangia. The female conceptacles are in most cases empty or contain merely 

 remains of carpospores. The cortex is differentiated into a hypothallus and a perithallus. 

 The cells of the perithallus are rich in starch. Ldthophyllum africannm Foslie occurs on Anno- 

 bon. This species forms cornice-like projections from the rock 15 cm. or even 30 cm. broad. 

 The little fan-shaped ends of the inconspicuous branches are arranged story-like on the sur- 

 face of the mass. L. Kolschyanum linger is next described. This species is often attar 

 to the larger species, L. africanum. It has a thin crust with a different type of branching. 

 The crust does not show a real hypothallus with cells running at an angle to those of the peri- 



BOT\NICAL ABSTRACTS. VOI . V, NO. 1 



