other times, by the cohesion of the anthers
(Syngenesia), in which latter case the union is generally very slight.
It must be remembered, however, that the so-called cohesion of the
filaments is in many cases due rather to the formation of compound
stamens, _i.e._ 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_, in which the
stamens were so united together as to form a tube open at the top like a
follicle.[28] This is an exaggerated degree of that fusion which exists
normally in _Salix monandra_, in Cucurbits and other plants.

=Cohesion of the pistils= is also of very frequent occurrence in plants,
under ordinary circumstances, but is less commonly met with than might
have been expected as a teratological phenomenon.

Further details relating to cohesion of the various parts of
the flower are cited in Moquin-Tandon, 'El. Ter. Veg.,' p. 248;
'Weber. Verhandl. Nat. Hist. Vereins f. d. Preuss. Rheinl. und
Westphal.,' 1860, p. 332, tabs. 6 et 7.

=Formation of ascidia or pitchers.=--In the preceding paragraphs, the
formation of tubular or horn-like structures, from the union of the
margins of one organ, or from the coalescence, or it may be from the
want of separation of various organs, has been alluded to, so that it
seems only necessary now, by way of summary, to mention the
classification of ascidia proposed by Professor Charles Morren[29], who
divides the structures in question into two heads, according as they are
formed from one or more leaves. The following list is arranged according
to the views of the Belgian savant, and comprises a few additional
illustrations. Those to which the ! is affixed have been seen by the
writer himself; the * indicates the more frequent occurrence of the
phenomenon in some than in other plants. Those plants, such as
_Nepenthes_, &c., which occur normally and constantly, are not here
included. Possibly some of the cases would be more properly classed
under dilatation or excavation.

ASCIDIA.

A. _Monophyllous_.

1. Sarracenia-like pitchers, formed by a single leaf, the edges
of which are united for the g