diff --git a/plant-ontology.obo b/plant-ontology.obo
index d6bc4ab..302e759 100644
--- a/plant-ontology.obo
+++ b/plant-ontology.obo
@@ -2357,7 +2357,7 @@ id: PO:0001180
 name: plant proembryo stage
 namespace: plant_structure_development_stage
 def: "A plant embryo development stage (PO:0007631) that occurs during the interval between the first cell division of a plant zygote (PO:0000423) and the onset of the plant globular embryo stage (PO:0001185)." [APweb:Glossary, POC:Laurel_Cooper, TAIR_curator:Katica_Ilic]
-comment: The plant proembryo stage occurs prior to the differentiation of the three main tissue systems (vascular system (PO:0000034) epidermis (PO:0005679); and the portion of ground tissue (PO:0025059)).
+comment: In the case of a nucellar (adventitious) plant embryo (PO:0004537), somatic plant embryo (PO:0025302), microspore-derived cultured plant embryo (PO:0025305), or other embryos that arise through apogamy, the plant proembryo stage (PO:0001180) begins after the division of a single cell that is not a zygote. The plant proembryo stage occurs prior to the differentiation of the three main tissue systems (vascular system (PO:0000034) epidermis (PO:0005679); and the portion of ground tissue (PO:0025059)).
 subset: Angiosperm
 subset: Arabidopsis
 subset: Maize