KEY TO THE DIFFERENT TRICHOME TYPES ON LEAVES AND FLORAL BRACTS OF ACANTHOPSIS HARV.:

1a. Trichomes non-glandular ....................................................................................................................... 2

1b. Trichomes glandular .............................................................................................................................. 5

2a[1]. Trichomes relatively thin-walled with a broad lumen (> ⅓ of cell diameter); uni- or multicellular; surface ornamented ........................................................................................................................................... 3

2b. Trichomes thick-walled with a narrow lumen (<¼ of cell diameter); uni- or multicellular; surface smooth or with helical pattern ............................................................................................................................ 4

3a[2]. Trichomes unicellular ................................................................................................................... Type A

3b. Trichomes multi-cellular; nodes often slightly swollen .................................................................... Type B

4a[2]. Trichomes unicellular ..................................................................................................................... Type C

4b. Trichomes multi-cellular; nodes distinctly swollen .......................................................................... Type D

5a[1]. Trichomes sessile or subsessile to short (usually <200 µm long); stalk, if present, 1- or 2(3)-celled .......... 6

5b. Trichomes long (nearly always> 250 µm); stalk 3-celled................................................................. Type G

6a[5]. Trichomes sessile or subsessile; stalk, if present, 1-celled ................................................................. Type E

6b. Trichomes short; stalk 2 (or 3)-celled............................................................................................... Type F