Extracellular signal peptide that regulates cell fate. Represses tracheary element differentiation but promotes the formation of procambial cells. Expressed at low levels in seedlings, roots and inflorescence. The O-glycosylation (arabinosylation) of the hydroxyproline Pro-82 enhances binding affinity of the CLE42p peptide for its receptor. Belongs to the CLV3/ESR signal peptide family.