This crossword No. 9160 clues and answers were published on Fri 10 Sep 1999 and the puzzle can be visited by following The Guardian Quick Crossword No. 9160 link.
All Across Clues and Answers:
5-across – London club for the learned : ATHENAEUM
8-across – Hurt : PAIN
9-across – Exchequer – store for valuables : TREASURY
10-across – Salad plant : ENDIVE
11-across – Aquatic sport : ROWING
13-across – Mark of disgrace : STIGMA
15-across – Wild plant – horse : SORREL
16-across – Wild plant like snapdragon : TOADFLAX
18-across – Welcoming – getting close! : WARM
19-across – Wild plant with clock : DANDELION
All Down Clues and Answers:
1-down – Wild plant best not touched : STINGING
2-down – : NETTLE
3-down – Progress of working life : CAREER
4-down – Unnecessary agitation : FUSS
6-down – Flower like pink : CARNATION
7-down – Wild plant for sauce : CRANBERRY
12-down – Herb used in absinthe : WORMWOOD
14-down – Refer : ALLUDE
15-down – Score in tennis when tie-break is called : SIXALL
17-down – Wild plant, also called archangel : DEAD
This crossword has in total 20 where 10 are across and 10 are down.