34 MISSOURI BOTANICAL GARDEN. 
to avoid such use of words ending in -otdes, renamed it 
Oxydectes* in 1735, though in 1737 he changed it to Cro- 
ton.t It remained practically intact till the second quarter 
of the present century. The first monograph was by Gei- 
seler { in 1807, who enumerated about one hundred and 
twenty species. Afterwards, the genus received considerable 
attention in a scattered way, many sections being segre- 
gated and new genera split off from it, chiefly by Klotzsch, 
though most of his genera were subsequently reunited under 
Croton. Baillon presented the result of his studies of the 
Euphorbiaceae in the Parisian herbaria in 1858 in an elabo- 
rate work. He divided the forms covered by this paper, 
into nineteen sections, besides recognizing five genera now 
included under Croton. The last and most comprehensive: 
work was by Jean Mueller von Argau,§ and his arrange- 
ment is the one generally accepted at the present time and 
has been the basis of my own study.|| Of the ten sub- 
genera recognized by Mueller, seven are represented in our 
territory, three of which are aberrant groups peculiar to 
this region. 
Croton, like other Euphorbiaceous genera, has few spe- 
cies that admit of a rigid definition of characters. In a 
restricted locality few variations will be noticed. Espe- 
cially is this true of C. Texensis (Klotzsch) Muell. Arg., 
and yet the extreme western, the extreme northern and 
extreme southern forms are in habit characters noticeably 
different. All Crotons are more or less pubescent, either 
scaly or stellate, and the particular form of these trichomes 
is often peculiar to a species or higher group. And indeed, 
* Linnaeus, Syst. Nat. 1735. 
+ Linnaeus, Gen. Plant. 288. 1737; Crit. Bot. 37, 1737. 
t Geiseler, Crot. Monog. 1807. 
§ Muell. von Arg., in DC. Prod. 15%: 512 to 700, 1866; and in Martius, 
Flor. Bras. 11? 3 82 to 274. F. 1873. 
|| See Bentham, in Benth. and Hook. Gen. Plant. $3293 to 296. 1880; 
also Journ. Linn. Soc. Bot. 173223. 1878. Pax, in Engl. and Prantl, 
Pflanzenfamilien 3°: 37 to 40. Ap. 1890. 
