372 
Tricotylous Races. 
perennial plants, the transition from one mode of ar- 
rangement to the other has been frequently observed 
on the same axis, as DELFINO has shown, I need not 
enter further into it now. Sometimes it happens also 
that the main stem of a tricotylous plant bears its leaves 
in quaternary whorls (Scabiosa atropurpurca). 
Fasciations are a frequent consequence of tricotyly, 
though they sometimes do not 
appear until late in the life 
of the plant. Mercurialis an- 
nua and Amarantus speeiosus 
furnished a series of instances 
nearly every year during sev- 
eral years of culture. In the 
former species they usually 
appear low on the stem; in 
the latter not below the in- 
florescence (See Fig. 83, p. 
399). My tricotylous race of 
Mercurialis anmia furnished 
almost all forms of fasciation. 
Fig. 77 represents a tricotylous 
plant whose stem was split 
from the first node after the 
cotyledons, and was therefore 
only fasciated in the epicotyl- 
ous internode. Between this condition and a flat stem 
one centimeter broad, and much contorted, all inter- 
mediate stages are presented by this species. In the 
spring of 1887 I collected a large group of hemi-tricotyl- 
ous, tricotylous and tetracotylous seedlings (See Fig. 
70) of Acer Pseudo-Platanus not far from Hilversum 
and grew them for several years. Most of them I threw 
Fig. 77. Mercurialis annua. 
A, tricotylous seedling with 
split stem ; B, a seedling the 
first whorl of leaves of 
which was ternary ; C, hemi- 
tricotylous plant (1900). 
