I am studying the R package Monocle:

There is function for analyzing Branches in Single-Cell Trajectories. I am confused that how to identify these trajeatories.

For example Analyzing Branches in Single-Cell Trajectories http://cole-trapnell-lab.github.io/monocle-release/docs/#analyzing-branches-in-single-cell-trajectories

and Pseudotime stretcheded

http://Analyzing%20Branches%20in%20Single-Cell%20Trajectories

I am confused about trajectories in these two pictures.

I am appreciate that you help me figure out.