138 BOTANICAL GAZETTE [aucust 
having two integuments, the outer being transformed in some cases into the 
so-called aril. This means that no sporophyll or carpel is present in tht 
group. 
This view of the seminiferous scale, which combines the old and separalt 
views that it is an axillary shoot, or a ligular or placental outgrowth, ot 
an outer integument, is certainly ingenious, but has the merit of explaining 
the well-known varying and transitional abnormalities, the reversed orients 
tion of the bundles, and the diverse structures of such forms as Abies 
Cupressus, Podocarpus, Taxus, etc.—J. M. C 
A WIDENING KNOWLEDGE of reproduction in the lower forms has shown 
that the line between sexual and asexual reproduction is not so sharp as ¥® 
formerly imagined and suggests that even in higher plants where parthen 
genesis does not normally occur it might possibly be induced by artificial 
means. The only clearly proven case of parthenogenesis in spermatophylé 
is furnished by Juel in his account of Antennaria alpina, Shaw's experimett 
led him to believe that in Marsilea Drummondit parthenogenesis may occu! 
under hormal conditions. : 
Shaw’s work has been confirmed by A. Nathanson,” who finds that 
M. Drummondii about go per cent. of the megaspores produce parthenog® 
netic embryos. J. vestita was then tried, but the isolated meé; 
under otherwise normal conditions produced no embryos. %¥ osefth 
attempts to induce parthenogenesis by using chemicals were unsie a 
but by raising the temperature parthenogenetic embryos were obtained. Bs 
a lot of 750 isolated megaspores at the temperature of the room ~~ 
embryo was found; but in a lot of 466 spores, at a temperature of 35 Ce 
parthenogenetic embryos developed. These embryos when placed hare 
soil continued to develop exactly like embryos resulting from ag a 
cells, “a | 
In M. macra 101 isolated megaspores at the temperature of ee. 
failed to produce a single embryo, but out of 67 megaspores, at a tem | 
ture of 35° C., eight developed parthenogenetic embryos. enti : 
The writer satisfied himself that the embryos were truly parthenog a 
and not merely adventitious.— CHARLES J. CHAMBERLAIN. 3 
hybridization, The work thus far undertaken has been mainly 0? 
grapes, pineapples, apples, pears, wheat, corn, and cotton. The 3 
one of progress rather than of practical improvement, and so te 
results are apt to be even more important than the horticultural results es 
; 1 Tempe 
Ueber Parthenogenesis bei Marsilea und ihre Abhangigkeit vo? der Fe a 
tur. Ber. d. deutsch. bot. Gesell. 18: 99-110. 1900. os 
