test
node1
BFO:0000004
independent
continuant
node1->node1
node2
BFO:0000040
material entity
node1->node2
node4
PO:0025131
plant anatomical
entity
node2->node4
node3
BFO:0000002
continuant
node3->node1
node3->node3
node5
PO:0009011
plant structure
node4->node5
node7
PO:0009002
plant cell
node5->node7
node6
BFO:0000001
entity
node6->node3