re BOTANICAL GAZETTE [JANUARY 
contaihs paired nuclei, which by fusion form a single nucleus in the mature basid- 
ium; the basidiospores are of course uninucleate, as is the mycelium that arises 
directly from them. Somewhere in the history of the mycelium the single nuclei 
must become paired. This will correspond exactly to the period of the aecidium 
in the life history of a rust, and must represent the time when an ancestral gamet- 
ophyte developed sexual organs, now suppressed, and passed over to a sporo- 
phyte generation. The paired nuclei probably arise, as in the rust, by the union 
of neighboring cells in the mycelium, a process of apogamy, at the period when 
the sexuality is due. 
It is important to note that the simpler types of life histories in the Uredinales 
where an aecidium is omitted must be regarded as derived from the ew and opsis 
forms by the entire suppression of cells which represent female sexual organs, 
and such life histories are in essential agreement with those of the ae 
which stand at the extreme in the process of reduction —B. M. Davi 
Jutes LAuRENT’S has given a detailed account of his experiments on the car- 
bon nutrition of green plants. While the old humus theory was long ago aban- 
doned, largely by reason of the work of Lresic, the tendency in recent years has 
been to hold to the utilization of organic foods to some extent, at least, by normal 
autotrophic plants. Boum, E. Laurent, and Acton have conducted rather 
conclusive experiments along this line, and a moderate amount of heterotrophic 
nutrition on the part of autotrophic plants is accepted by PFEFFER and Jost. 
The most conclusive experiments upon which this view may be based are those 
here considered, whose publication in full has been long awaited, since a 
preliminary notice was published in the Comptes Rendus for 1898. The chief 
reason for reposing confidence in Laurent’s work is because he has worked 
with aseptic media, according to the most approved modern technique. Experi- 
ments with maize roots in contact with glucose solutions, in addition to DETMER’S 
solution, resulted in an increase of dry weight in the dark, whereas control cul- 
tures in DeTMER’s solution only failed to show such increase in weight. Maz&é 
has secured a like result with the vetch. Cultures in an atmosphere deprived 
of CO,, but exposed to light showed an increase of weight due to an intake o 
glucose by the roots. Various plant species, previously deprived of starch, whose 
roots were placed in 1 to 5 per cent. glucose solutions, the plants being placed under 
a bell-jar, over a potash solution and exposed to sunlight, showed the formation 
of papas from glucose that had been taken in by the roots. Similar results were 
tained in darkness, perhaps because less gl absorbed. Autophytes 
are found to differ from ‘eaptaphytes not only quantitatively, as appears from the 
above, but also more fundamentally. Careful experimentation failed to disclose 
any power on the part of the roots of green plants to digest starch, a power pos- 
sessed by holosaprophytes. A chapter is devoted to the consideration of the 
; io i eta mies J.: Recherches sur la nutrition carbonée des plantes vertes & l’aide 
188-203; 231-242 1904. 
de matitres organiques. Rev. Gén. Bot. 16:14-48; 66-80; 96-128; 155-1665 2 
nC eee 
