452 BOTANICAL GAZETTE [JUNE 
Portraits of botanists —In 1903 WiTrRock published a set of photographs 
of botanists selected from the collection at the botanical garden at Stockholm. 
A second series has now been issued,'' containing full-page portraits of too bot- 
_ anists arranged chronologically from Aristotle to Goebel; and 51 additional 
plates, each containing 6 portraits. The biographic notes contain a large amount 
of information which must have been brought together with great labor.—J. M. C. 
British Desmidiaceae.—In 1904 the first volume of this work was issued 
as a publication of the Ray Society. The second volume has now appeared,*? 
containing the genera Euastrum (46), Micrasterias (18), and Cosmarium (50). 
NOTES FOR STUDENTS. 
Regeneration.—The number of recent papers dealing with regeneration 
indicates a marked activity in this field of investigation. The work of [RMISCH 
and others has made us familiar with the fact that the hypocotyls of a number 
of plants can produce adventitious buds. “In some cases these occur normally, 
but in others only in the presence of more unusual conditions of growth. BURNS 
and HEDDEN"S have investigated these conditions, using seedlings of Linaria 
bipartita splendida, Antirrhinum majus, and Linum usitatissimum. They 
confirm KisTER’s results that when the cotyledon or the main vegetative tip 
is cut away the tendency toward the development of adventitious buds is greatly 
increased. On uninjured seedlings of Antirrhinum which do not stand erect 
but are horizontal, buds arise only on the upper side, and when these plants 
are fastened so that they must remain erect they produce no buds. The effect 
of a moist atmosphere is to increase the number of buds and the rapidity of 
their development. The same is true of higher temperature. The older parts 
of the hypocotyl have a much greater capacity to produce buds than the younger 
parts, and there is no tendency at all to bud production on the part of the hypo- 
cotyl still elongating. Gravity seems to have no influence. Light, on the other 
hand, is a necessary condition, for in one-sided illumination buds appear only 
on the illuminated side, on a klinostat in the light on all sides equally, and in 
the dark not at all. Experiments are mentioned which indicate that wounding 
is not a cause of the regeneration here. The explanation of the phenomena 
mentioned as given by the authors is that “‘when the cotyledons are removed 
11 WITTROCK, VEIT BRecHER, Catalogus illustratus iconothecae botanicae horti 
Bergiani ee ee notulis biographicis adjectis. Acta Hort. Berg. 3: No.3. 
p. xcili+245. pls. 151. 
* 
2 West, W., and 2 ee A monograph of the British Desmidiaceae. Vol. I. 
pp. X+206. pls. 32. London: Ray Society. 1 
‘3 BurNS, GEORGE P., and HEDDE Pia ., Conditions influencing regenera- 
tion of the hypocotyl. Beih. Bot. Coed 19: Suse 1906 
