Spores of Riccia Glauca

1906 Botanical Gazette  
phase a number of chromatic bodies (presumably derivatives of the chromosomes) are distributed on the lining fibers, and subsequently aggregate to form the lobular nucleolus of the resting nucleus. The first spore wall is cuticularized from a very early period, and within it, at the equatorial rim, a plug of mucilage is deposited. The second spore wall is formed within the first wall, and is also cuticularized; at first it appears homogeneous, but subseqently is composed of three regions. The
more » ... hree regions. The endospore (pectose and cellulose) is formed late, and is often separated from the second wall by a thin band of dark material.-J. M. C. Postelsia. I5---Four years ago the first volume under this title appeared,i6 containing seven papers by members of the Minnesota Seaside Station on the coast of Vancouver. The present volume is printed in the same handsome style, and also contains seven papers as follows: Observations on plant distribution in Renfrew district of Vancouver Island (pp. I-132. PIS. i-II), by C. 0. ROSENDAHL; The Conifers of Vancouver Island (pp. I33-2I2. pIS. I2-T5), by F. K. BUTTERS; Hepaticae of Vancouver Island (pp. 213-235), by ALEXANDER W. EVANS; Some western Helvellineae (p)p. 236-244), by D. S. HONE; Renfrewia parvkla, a new kelp from Vancouver Island (pp. 245-274. PIS. I6-I9), by ROBERT F. GRIGGS; A study of the tide-pools on the west coast of Vancouver Island (pp. 275-304, pIs. 20-25), by ISNBEL HENKEL; Some geological features of the Minnesota Seaside Station (\pp 305-347. pIs. 26-33), by C. WV. HALL. The paper on plant distribution reaches the conclusion that the pteridophytes are poor in species for so moist a region, that the gymnosperms constitute the great mass of the vegetation, and that the monocotyledons are more important than the dicotyledons. The paper on conifers contains very interesting observations, treats Picea, Tsuga, and Pseudotsuga as sections under Abies, and organizes a key to the northwestern genera on the basis of foliage. Ren-Jrewia is a new genus of kelps nearest to Laminaria and Cymathere.-J. M. C. Synapsis and reduction.-From a study of the pollen mother cells of Acer platanoides, Salomonia biflora, Ginkgo biloba, and Botrychium obliquUm CAR-DIFF draws the following conclusions.I7 Synapsis is a constant morphological character of the mother cell, and the unilateral position of the synaptic knot is probably due to. gravity. Previous to synapsis the chromatin is in two or more threads which arrange themselves in pairs, longitudinally, and finally fuse during synapsis, but there is not a complete mingling of chromatin substance in the chromatic thread. The thread splits longitudina11V in the first mitosis, probably along the line of previous fusion. The chromosomes are of different sizes and do not behave alike at the first mitosis. I5 The year book of the Minnesota Seaside Station. i906. PP. 364. pIs. 33. Obtained from Josephine E. Tilden, Univ. Minn., Minneapolis. $2.25. '6 BOT. GAZETTE 34:468. 1902. '7 CARDIFF, L D., A study of reduction and synapsis. Bull. Torr. Bot. Club 33:27i-306. pIs. 12-15-i906.
doi:10.1086/328974 fatcat:y6pm2dn6trgc7kztozwamro6cu