Feynman diagram for gluon exchange, time up, gluon horizontal.

[Spinnor]

Consider the Feynman diagram below from,

http://hyperphysics.phy-astr.gsu.edu/hbase/particles/expar.html

where I assume time runs upwards and the gluon in the graphic runs horizontal and is labled as a green_antiblue gluon. If the gluon runs horizontal can one still label a gluon as being green_antiblue? Only if the gluon is not horizontal can we specifically label it? Hope my question is not too confusing.

Thanks for any help!

 

[mfb]

You could label it blue anti-green as well, the "direction" of color flow can (and has to) be seen from the quarks if the diagram is drawn like this.