Before posting his final winning answer, gernot had posted a number of answers, each of which represented a single graphical component of the final picture. Once posting his final answer, he deleted the component answers.
For this answer, I lifted those pieces-parts from gernot's [since deleted] components and the OP's question, to demonstrate that, once you have all the components, one can use \stackinset to overlay them on the base graph, perhaps.
His components included the tikz parts identified in the following MWE as \spiralA, \spiralB, \degensink, \degensource,
\nondegensink, and \nondegensource,
\documentclass[10pt]{article}
\usepackage{pgf,tikz}
\usetikzlibrary{arrows}
\usepackage{mathrsfs}
\usepackage{amssymb,fancyhdr,txfonts,pxfonts}
\pagestyle{empty}
\usetikzlibrary{decorations.markings}
\usepackage{stackengine}
\renewcommand\stacktype{L}
\setstackgap{L}{8pt}
\begin{document}
\savestack\mygraph{%
\begin{tikzpicture}[%
line cap=round,
line join=round,
>=triangle 45,
x=1.0cm,
y=1.0cm%
]
%
\clip(-5.8,-3.58) rectangle (5.56,5.64);
\draw [line width=1.2pt] (0.,4.68)-- (0.,-0.74);
\draw [line width=1.2pt] (-4.,0.)-- (4.3,0.);
\draw [thick, domain=-2:2] plot (\x, {\x*\x});
\draw (3.62,-0.12) node[anchor=north west] {$\mathrm{Tr}\,A$};
\draw (-.4,5.1) node[anchor=north west] {$\scriptstyle\det A$};
\draw (-2.35,4.7) node[anchor=north west] {%
\stackunder{$\scriptstyle\Delta=0$}{$\downarrow$}};
\draw (1.08,5.1) node[anchor=north west] {\ensurestackMath{\stackunder[11pt]{%
\Longstack[l]{\scriptstyle\Delta=0: \scriptstyle\det A=\frac{1}{4}(%
\mathrm{Tr}A)^2}}{\downarrow}}};
\draw (1.,-1.)-- (-1.,-3.);
\draw (-1.,-1.)-- (1.,-3.);
\draw [dash pattern=on 2pt off 2pt] (-1.,-2.)-- (1.,-2.);
\draw [dash pattern=on 2pt off 2pt] (0.,-1.)-- (0.,-3.);
\end{tikzpicture}%
}
\savestack\spiralA{%
\begin{tikzpicture}
[decoration=
{markings,
mark=at position 0.1 with {\arrow{stealth}}
}
,scale=0.5
]
\draw (-4,0) -- (4,0);
\draw (0,-4) -- (0,4);
\draw[postaction={decorate},domain=27:7,variable=\t,smooth,samples=100]
plot ({\t r}: {0.005*\t*\t});
\end{tikzpicture}%
}
\savestack\spiralB{%
\begin{tikzpicture}
[decoration=
{markings,
mark=at position 0.99 with {\arrow{stealth}}
}
,scale=0.5
]
\draw (-4,0) -- (4,0);
\draw (0,-4) -- (0,4);
\draw[postaction={decorate},domain=10:28.5,variable=\t,smooth,samples=100]
plot ({-\t r}: {0.005*\t*\t});
\end{tikzpicture}
}
\savestack\degensink{%
\begin{tikzpicture}
[decoration=
{markings,
mark=at position 0.5 with {\arrow{stealth}}
}
,scale=0.5
]
\draw (0,-4) -- (0,4);
\draw[postaction={decorate}] (-4,0) -- (0,0);
\draw[postaction={decorate}] (4,0) -- (0,0);
\draw[postaction={decorate}] (-3.5,3.5) .. controls (4,1.5) and (4,1).. (0,0);
\draw[postaction={decorate}] (3.5,-3.5) .. controls (-4,-1.5) and (-4,-1) .. (0,0);
\draw[postaction={decorate}] (-3.5,2.5) .. controls (2,1) and (2,0.8).. (0,0);
\draw[postaction={decorate}] (3.5,-2.5) .. controls (-2,-1) and (-2,-0.8) .. (0,0);
\end{tikzpicture}%
}
\savestack\degensource{%
\begin{tikzpicture}
[decoration=
{markings,
mark=at position 0.5 with {\arrow{stealth}}
}
,scale=0.5
]
\draw (0,-4) -- (0,4);
\draw[postaction={decorate}] (0,0) -- (-4,0);
\draw[postaction={decorate}] (0,0) -- (4,0);
\draw[postaction={decorate}] (0,0) .. controls (4,1.5) and (4,1).. (-3.5,3.5);
\draw[postaction={decorate}] (0,0) .. controls (-4,-1.5) and (-4,-1) .. (3.5,-3.5);
\draw[postaction={decorate}] (0,0) .. controls (2,1) and (2,0.8).. (-3.5,2.5);
\draw[postaction={decorate}] (0,0) .. controls (-2,-1) and (-2,-0.8) .. (3.5,-2.5);
\end{tikzpicture}%
}
\savestack\nondegensink{%
\begin{tikzpicture}
[decoration=
{markings,
mark=at position 0.5 with {\arrow{stealth}}
}
,scale=0.5
,plotsettings/.style={postaction={decorate}}
]
\draw[postaction={decorate}] (0,-4) -- (0,0);
\draw[postaction={decorate}] (0,4) -- (0,0);
\draw[postaction={decorate}] (-4,0) -- (0,0);
\draw[postaction={decorate}] (4,0) -- (0,0);
\draw [plotsettings,domain=-2:0] plot (\x, {\x*\x});
\draw [plotsettings,domain= 0:2] plot (\x, {\x*\x});
\draw [plotsettings,domain=-2:0] plot (\x, {-\x*\x});
\draw [plotsettings,domain= 0:2] plot (\x, {-\x*\x});
\draw [plotsettings,domain=-3:0] plot (\x, {0.44*\x*\x});
\draw [plotsettings,domain= 0:3] plot (\x, {0.44*\x*\x});
\draw [plotsettings,domain=-3:0] plot (\x, {-0.44*\x*\x});
\draw [plotsettings,domain= 0:3] plot (\x, {-0.44*\x*\x});
\end{tikzpicture}%
}
\savestack\nondegensource{%
\begin{tikzpicture}
[decoration=
{markings,
mark=at position 0.5 with {\arrow{stealth}}
}
,scale=0.5
,plotsettings/.style={postaction={decorate}}
]
\draw[postaction={decorate}] (0,0) -- (-4,0);
\draw[postaction={decorate}] (0,0) -- (4,0);
\draw[postaction={decorate}] (0,0) -- (0,-4);
\draw[postaction={decorate}] (0,0) -- (0,4);
\draw [plotsettings,domain=0:-2] plot (\x, {\x*\x});
\draw [plotsettings,domain=2: 0] plot (\x, {\x*\x});
\draw [plotsettings,domain=0:-2] plot (\x, {-\x*\x});
\draw [plotsettings,domain=2: 0] plot (\x, {-\x*\x});
\draw [plotsettings,domain=0:-3] plot (\x, {0.44*\x*\x});
\draw [plotsettings,domain=3: 0] plot (\x, {0.44*\x*\x});
\draw [plotsettings,domain=0:-3] plot (\x, {-0.44*\x*\x});
\draw [plotsettings,domain=3: 0] plot (\x, {-0.44*\x*\x});
\end{tikzpicture}%
}
\stackinset{c}{-55pt}{c}{2pt}{\stackunder[24pt]{$\vcenter{\hbox{\scalebox{.3}{%
\nondegensink}}}$}{\scriptsize\Longunderstack[l]{sink}}%
}{%
\stackinset{c}{60pt}{c}{2pt}{\stackunder[24pt]{$\vcenter{\hbox{\scalebox{.3}{%
\nondegensource}}}$}{\scriptsize\Longunderstack[l]{source}}%
}{%
\stackinset{c}{-71pt}{c}{56pt}{\stackunder[24pt]{$\vcenter{\hbox{\scalebox{.3}{%
\fbox{\degensink}}}}$}{\scriptsize\Longunderstack[l]{degenerate sink}}%
$\!\rightarrow$}{%
\stackinset{c}{78pt}{c}{56pt}{$\leftarrow\!$%
\stackunder[24pt]{$\vcenter{\hbox{\scalebox{.3}{%
\fbox{\degensink}}}}$}{\scriptsize\Longunderstack[r]{degenerate source}}%
}{%
\stackinset{c}{-20pt}{c}{62pt}{\stackunder{\scalebox{.35}{\spiralA}}{%
\scriptsize spiral sink}}{%
\stackinset{c}{27pt}{c}{62pt}{\stackunder{\scalebox{.35}{\spiralB}}{%
\scriptsize spiral source}}{%
\mygraph%
}}}}}}
\end{document}
