So what is this structure on topped stem?

[Dewey Matter]

Just doing some LST and photos, noticed this...what is it?

 

[Padawan1972]

Just doing some LST and photos, noticed this...what is it?

View attachment 1002439 View attachment 1002440

calyx normal to see those at each branch site

 

[Dewey Matter]

Thank you, just looked weird seeing only the one.