1908] CURRENT LITERATURE 317 
effect the production of sexual organs were haemoglobin and leucin, as found 
also by Kiegs. The effect of nutrition upon the differentiation of reproductive 
- and vegetative processes was amply confirmed; but not all species produce 
sexual organs under the same conditions, showing a physiological as well as a 
morphological distinction. S. hypogyna, in which true antheridia do not develop, 
was made to develop antheridia under proper nutrient conditions. The varia- 
tions induced were so extensive as to include all the characters used for diagnostic 
purposes, and the author makes the suggestion that a species can be defined in 
terms of its behavior in an established standard culture. The conclusion is 
reached that there are a great many entirely distinct forms, physiologically so 
at least, which may be regarded as elementary species in the sense of DEVRIES. 
The whole tendency of the investigation is to confirm the doctrine that sex in 
plants is determined by external conditions.—J. M. C. 
: The Sporangiophore.—Miss BENSON?? has emphasized the morphological 
mportance of the sporangiophore, and has extended its application. Originally 
applied in Sphenophyllales, Equisetales, and Psilotales, she would extend its 
application to all pteridophytes. Objection is made to BoweERr’s application of 
the term in Ophioglossales to the ‘‘fertile spike.” In the Filicales the sorus (or 
Synangium) is the sporangiophore; while in Lycopodiales it appears in a 
teduced” formas the subarchesporial pad. Primarily it is a unit structure that 
appears on the axis, but may be “taken up on to” the leaf, as in all known ferns 
and many Lycopsida. The definition suggested is that “‘a sporangiophore is a 
Structure characteristic of the sporophyte of Pteridophyta, and consists of a 
central, generally pedicellate mass of sterile tissue, with sporogenous regions 
: Pying one or more sporangia, which may be terminal, lateral, or basal.” 
It is further suggested that even Cordaitales and Taxineae may be forms whose 
Sporangiophores have never been “taken up” on leaves. All this means 4 
monophyletic origin for pteridophytes, with the sporangiophore (as now defined) 
as a fundamental and unifying structure of the sporophyte. Such a hypothesis 
fees .s about, and it has enough facts to support it to make it seduc- 
aes Cc 
seta Nymphaeaceae, Cabombaceae, and Ranunculaceae. Recently VAN 
So ‘eM’? has discovered this singular structure in Sorghum halepense Pers. 
far only the monostelic structure has been observed in the aerial and sub- 
a — be f the numerous Gramineae examined. While the aerial send 
oe a is monostelic, the rhizome possesses a large number of meristeles 
oe BENson, M., The sporangiophore—a unit of structure in the Pteridophyta. 
Phytol. 7:143-149. 1908. 
“ag Ttecnem, Pu., Une graminée & tige shizostélique. Ann. Sci. Nat. Bot. 
IX, 52371. 1907. 
