OF THE STAMENS, ETC. 99 
normal circumstances, the petals become fused together 
by their edges along their whole extent, at the base 
only, at the apex only, as in the Vine, or at the base 
and apex, leaving the central portions detached. In- 
dications of the junction of the petals may generally 
be traced by the arrangement of the veins, or by the 
notches or lobes left by imperfect union. In Crocuses 
I have frequently met with cohesion of the segments 
of the perianth, by means of their surfaces, but the 
union was confined to the centre of the segment, 
leaving the rest of the surfaces free. 
Cohesion of the stamens— Under natural circumstances, 
cohesion of the stamens is said to take place either by 
the union of their filaments, so as to form one, two, 
or more parcels (Monadelphia, Diadelphia, Poly- 
adelphia) ; at other times, by the cohesion of the 
anthers (Syngenesia), in which latter case the union is 
generally very shght. It must be remembered, how- 
ever, that the so-called cohesion of the filaments is in 
many cases due rather to the formation of compound 
stamens, 7. ¢. to the formation from one original staminal 
tubercle of numerous secondary ones, so that the 
process is rather one of over development than of 
fusion or of disjunction. ‘These conditions may be met 
with as accidental occurrences in plants or in flowers, 
not usually showing this arrangement. Thus, for 
instance, Professor Andersson, of Stockholm, describes 
a monstrosity of Salix calyculata, m which the stamens 
were so united together as to form a tube open at the 
top like a follicle." This is an exaggerated degree of 
that fusion which exists normally in Salia monandra, 
in Cucurbits and other plants. 
Cohesion of the pistils is also of very frequent oc- 
currence in plants, under ordinary circumstances, but 
is less commonly met with than might have been ex- 
pected as a teratological phenomenon. 
1 * Journal of the Linn. Soc. Bot.,’ vol. iv, p. 55. 
