oe AMERICAN FERN JOURNAL 
fern book ever issued. With its 744 pages, including 
_ 23,499 specific names, it bears about the same relation to 
fern study that a dictionary bears to the study of a foreign 
age. Since this much needed task was com- 
. pleted, Mr. Christensen has published a number of im- 
_ portant monographic papers dealing especially with the 
_ genus Dryopteris. Three of his shorter papers have 
_ appeared in the American Fern JourNat, and it is with 
__ aview of making readers of the Journat better acquainted 
_ with Mr. Christensen that the present article is written. 
_ Carl Frederik Albert Christensen was born in a village 
No on the island of Lolland in South Denmark on the 16th 
— of January 1872. His early education was obtained in- 
the elementary and higher schools of the island of Falster. 
_ In 1888 he went to a secondary school in Copenhagen to — 
prepare for the entrance “examen” of the University of | 
sie 86 & profemion, but after this he decided Oi 
ee natural science, particularly botany, which = 
eo had hee Hes: a favorite. pursuit of his. His teacher in 
ae ‘this subject was Prof. Eu genius Warming. Beside 
botany, oe he studied also physics, chemistry, zoology, 
ae mays and geology — In 1900 he received the degree 
of] Master of Science from the university. Since then he 
- : - worked j in the library and museum of the university, eS 
- - has taught i in the secondary schools. The botanical — 
i library there is ‘particularly: Tich in old literature, which : 
| Sotiegtomes | oe setae ag en of the 
___ 1m October 1900 he was married to Miss Aff Derschen. 
‘Since then three — have been born. = 
