It looks like it might be a type of vine or trailing plant.
Lemon tree leaves has these harden dots ontop of the leaves
13 (32) Mossel Bay Post Office Tree - Historic tree believed to have been the tree in which an old shoe was placed for exchange of messages by Portuguese seafarers in the 16th century - Dias Museum 1 Market Street Mossel Bay Western Cape S 34º 10.819’ E 22º 08.486’ Height: 8.5m Stem size: 2.3m circ; 2.66m (multi-stemmed ) Crown size: 32.1m & 33.7m