234 BOTANICAL GAZETTE [MARCH 
PARTHENOGENESIS in Taraxacum and Hieracium is being investigated by 
MvrBECK.?° Two species of Taraxacum were studied, T. vulgare (Lam.) Raunk., 
which produces abundant, but imperfect pollen, and 7. speciosum Raunk., which 
produces no pollen at all. e embryo-sacs present nothing unusual in their 
appearance. The egg cell increases in size, its nucleus divides, and the embryo 
is formed just as if normal fertilization had occurred. The polar nuclei fuse and 
then divide, giving rise to the endosperm. 
Three species of Hieracium were examined, H. grandidens Dahlst., H. ser- 
ratijrons Almqu., and H. colophyllum leiopogon Gren. In general, the embryo- 
sac resembles that of Taraxacum. The embryo is developed from the egg, and 
embryos are formed in eighty per cent. or ninety per cent. of the flowers, so that 
it is probable that these species are always parthenogenetic. A full account with 
illustrations is to follow.—C. J. CHAMBERLAIN. 
Miss Cootrys° has given an account of the ecology of the tamarack, which 
has been based upon a considerable amount of field study in various states. 
Attention is called to the unusally wide range of the tree, which occurs in five of 
MeERRIAM’s zones. The tree displays great vigor even at the extreme northern 
and southern limits. The range of topographic habitat is also wide; although 
commonly thought of as a swamp tree, it occurs in almost every habitat, even to 
the most xerophytic. Among the characteristics which may serve to give this 
tree its great success, Miss Cootey mentions the abundance of seeds, the fre- 
quency with which the tree produces seeds, the power of the seedlings to endure 
light, indifference to soil, and rapid growth. A great disadvantage is the inability 
of the tree to endure shade, or to compete with other forest trees. In a Maine 
area a tamarack swamp has succeeded a hardwood forest.—H. C. COWLES. 
Apocamy in Hieracium is described by OSTENFELD,3? who in 1903 in a paper 
written conjointly with RAUNKIAER reported that twenty-two species of the genus 
had been found to produce seeds even after pollination had been prevented. 
OsTENFELD now finds that many of the seeds thus produced germinate normally. 
In the botanical garden at Copenhagen two species of Hieracium were found 
which produce only female flowers, a careful examination showing not 4 single 
was not determined. Attempts to germinate the pollen of pollen-bearing a2 
failed. This would indicate that the great number of forms in the genus, US" : 
attributed to hybridization, are due rather to mutation. All attempts to er 
ybrids were unsuccessful—C. J. CHAMBERLAIN. 
29 MURBECK, Sv., Parthenogenese bei den Gattungen Taraxacum und Hieracium- 
Bot. Notiser 1904: 285-296. 
3° CooLEy, Grace E., Silvicultural features of Larix americana. F 
Quarterly 2: 148-160. 1904. 
3t OsTENFELD, C. H., Zur Kenntniss der Apogamie in der Gattung Hiera 
Ber. Deutsch. Bot. Gesells. 22: 376-381. 1904. 
orestry 
cium. 
