38 



SCIENCE 



[N. S. Vol. XXXIX. No. 992 



gave wholly negative results, not a single seed 

 developing. This race of gigas came from an 

 independent source, having originated, appa- 

 rently by a mutation, in the Palermo Botanical 

 Garden.^ Theoretically, it might have been 

 anticipated that the eggs of these plants, hav- 

 ing already the diploid number of chromosomes 

 (14) v^ould be most likely to shovr a tendency 

 to apogamy, but so far as the evidence goes 

 this does not appear to be the case. The un- 

 balanced chromosome number (15) in lata 

 might on the other hand perhaps be expected 

 to predispose megaspores or egg cells of lata 

 having this number of chromosomes (assuming 

 that such occur) instead of the reduced num- 

 ber, to degeneration. 



Nevertheless, from the observation by Geerts 

 of a megaspore mother cell of LamarcTciana 

 containing 28 chromosomes, and from the dis- 

 covery, by Miss Lutz^ and Stomps,* of tri- 

 ploid mutants containing 21 chromosomes, it 

 seems quite certain that eggs containing 14 

 chromosomes must occasionally be formed in 

 Lamarchiana. Why such cells might not 

 develop embryos occasionally, even if unfer- 

 tilized, is not clear, and perhaps an extensive 

 series of experiments v/iih Lamarchiana and 

 some of its 14-chromosome derivatives may 

 yet show that this type of apogamy sometimes 

 occurs. 



In the light of these facts it appears desir- 

 able that the experiments of Mrs. Rose Haig- 

 Thomas^ on apogamy in 0. hiennis be repeated 

 before the results are accepted as facts. 



1 may add that I have very recently ob- 

 served a case of parthenocarpy in a race of 0. 

 muricata L. from eastern Canada grown in 

 my cultures this season. This culture con- 

 tained only four plants, all alike. Earlier in 



2 Gates, R. E., ' ' Tetraploid Mutants and Chrom 

 osome Mechanisms," Biol. Centlbl., 33: 92-99 

 113-150, Figs. 7, 1913. 



3 Lutz, Anne M., ' ' Triploid Mutants in CEno^ 

 thera," Biol. Centlbl., 32: 385-435, Figs. 7, 1912, 



■1 Stomps, Theo. J., ' ' Mutation bei CEnothera 

 biennis L.," Biol. Centlbl., 32: 521-535, PI. 1 

 Fig. 1, 1912. 



5 Haig-Thomas, Mrs. Rose, ' ' Note sur la parthfi' 

 nogenSse chez les plantes, " Comptes Sendus, TV' 

 Conf. Intern, de Genetique, Paris, 1913, p. 209. 



the season normal capsules were produced 

 filled with seeds, but the later capsules (ob- 

 served November 19) though full size and with 

 normally developed walls, were hollow, con- 

 taining undeveloped ovules instead of seeds. 

 It seems possible that the drop in temperature 

 at the end of the season may have been suffi- 

 cient to kill the young embryos shortly after 

 the eggs were fertilized, while the capsule 

 walls, already stimulated by the process of 

 fertilization, continued their development. 

 However, nothing of the kind was observed in 

 any other race. 



E. E. Gates 

 Universitt of London 



SOCIETIES AND ACADEMIES 



THE AMERICAN PHILOSOPHICAL SOCIETY 



On November 7, before the American Philo- 

 sophical Society, a paper was read by Professor 

 J. M. Macfarlane on "The Phylogeny of Plants 

 in Relation to their Environment. ' ' Recalling the 

 conclusions already published in the centennial 

 volume of the Academy of Natural Sciences, the 

 speaker showed that, of the simplest non-nucleate 

 plants the great majority seem to have had a 

 thermal-water or fresh-water origin. Of the 

 simpler nucleate plants, such as the Desmids, the 

 Protococcoid, Pleurococcoid, Cheetophoroid, Clado- 

 phoroid and related groups, all or the prepond- 

 ating number were fresh-water. Even the simplest 

 brown algffi like Lithoderma, Pleurocladia and 

 Heribaudiella were now in part or wholly fresh- 

 water, as were the simplest groups of the red alg£e. 

 An estimation of the genera and species of algae 

 and fungi now living revealed that 3,008 genera 

 and about 28,660 species were fresh-water or land 

 forms, 658 genera and 5,930 species were marine. 

 Interesting data were advanced as to transition or 

 brackish species. The phylogenetic origin of 

 bryophytic, pteridophytic and higher classes from 

 certain fresh-water algse was advocated, while the 

 extreme rarity of any genus of these classes in ma- 

 rine surroundings was emphasized. The speaker, 

 therefore, concluded that marine life was probably 

 derived from a thermal-water and later from a 

 fresh-water source. Though contrary to the whole 

 trend of zoological consideration, he indicated that 

 in an abstract already published he had advocated 

 a like origin in fresh water for animal as for plant 

 life, and a derived distribution of many groups of 

 animals into the sea. 



