256 



THE AMERICAN NATURALIST 



[Vol. XL 



these views, and it was only when Schacht himself discovered in 

 Gladiolus segeium ( o8a) a case in which the embryo undoubtedly 

 originated in a cell which was in the embryo-sac previous to the 

 advent of the pollen tube, that the controversy practically came to 

 an end in favor of the views of Hofmeister and von IVIohl. 



Schacht ('60) reported variations in the structure of the pollen 

 grains of several gymnosperms. On page 143 of the article desig- 

 nated he says that the pollen of Cupressus sempervirens has a 

 slightly elongated roundish form, which has divided into two un- 

 equal cells when the anther opens. Thuja orientalis shows the 

 same relation, only here oftener than in Cupressus (italics are mine) 

 further division takes place in the larger cell. Two of these extra 

 divisions are shown in his Figures 22 and 23, Plate 17. The text 

 cited above implies that similar divisions are formed in Cupressus, 

 but none are figured. Schacht also found variations in the num- 

 ber of cells in pollen grains of Larix europcea, shown in his Figures 

 4 and 5. Since Schacht did not understand that one or more of 

 the cells first cut off in these pollen grains may disintegrate, it is 

 possible that his observations do not really mean a variation in 

 the total number of cells formed in Larix, but his figures seem to 

 the writer to indicate that he actually observed such a variation 

 in Lari.r ciiropd'a. He also states ('60, p. 144) that Abies pectinata 

 (Taniici. Pin a r„l;/aris (Fichte) [Picea excelsa L.], and Pinus 

 si/hrstris I KietVi ) are like Larix in the interior of the pollen grain, 

 only in the first two there are almost always three cells, and in the 

 latter sometimes only two. No figures are given for these, but it 

 seems probable that Schacht really observed variations in the 

 number of cells in the pollen of the species named. Schacht was 

 probably the first to figure the sperm cells ('58a) though he did not 

 understand their function. 



Hofmeister ('62, p. 406) described the structure in the pollen 

 of Juiu'perus, Taxus, and Thuja differently from what it is now 

 inidcrstood to 1k\ hut the apparent variation is probably due to a 



i„ 1S7J, ,v|„„„',i . v.,i'',ti„„ in ll„. nM,Ml,i'^V'ltf!"In,'i in tl,e 

 poll,-,, ..r rov,/,,:,„,,;Y"".'/./':'"'^Mi.|.^ II,- f.,„,„l ,hat ,.„.- 



