476 The Botanical Gazette. | November, 
vertically downwards, the rest of the root may occupy the horizontal 
or any other position, without the geotropic reaction following. By 
in an uninjured root only the root tip is geotropically sensitive. 
“A THEORY of the strobilus in oe ape is the title of a 
. Bower be of 
most suggestive paper rea y fore section D 
the B. A. A. S., and published in “the dene oF Botany 8: 343° -365. 
S 1894. It ought to be read in full by every botanist who 1s inter- 
ested in the questions of vegetable phylogeny. The main points a the 
theory are briefly stated by the author in these words: 
1. Spore production was the first office of the spor op and the 
spore phase has constantly recurred throughout the descent of the 
Archegoniatz; the spore bearing tissues are to be regarded a primary, 
a vegetative tissues as secondary, in point of evolutionary history. 
Other things being equal, increase in number of carpospores is an 
iinisie: a Fea of numerical spore production was attained in the 
vascular cryptogam d 
3. Sterilization of potential sporogenous tissue has been a wide- 
kara a ae ti appearing as a natural consequence of increased 
spore produc 
mee aan, ve ies or pci of cells (tapetum), served in many 
cases the direct function of nourishin ay the developing spores, being 
themselves aained during she’ proc 
5. By formation of a central mass se-alaaiedla, etc.) the spore pro- 
co pica was, in more complex forms, relegated to a more superficial 
6. ros vascular plants, parts of the sterile tissue formed septa, parte 
=F 
P 
; , 8 ey septation, may have taken place repeatedly in the same line 
o 
Q- The trobilus as a wholeis the correlative of a body of the nature 
of a sporogonial head, and the apex of the one corresponds to the 
Baia 
. Progression from the wong os more complex type de- 
SeNied upon (@) septation, and (4) e n to form superficial ap- 
pendicular organs see rangi Poke. “iporephalie’ upon which the 
soar ty bad a 
By continued pica} gr doin of the stobilus the number of sporo- 
phytis may ae indefinitely increased. nd 
i ane ger Pata as are kipceptible of great pedis in size aD 
iaeniplexity > Hed tan t of paca eels Lh agi small and sim- 
rilization of 
I 
sporophyl 
ene ner rere” 
tAnnals of Botany, 8: 317. S. 1894. 
