| 1. Nutlet marginal prickles in 2 or 3 rows, bases not or slightly widened, not in contact, not fused; uncommon alien |
| L. squarrosa |
| 1' Nutlet marginal prickles in 1 row, bases slightly or very widened, generally in contact, generally fused; common native |
| L. redowskii |
| 2. Nutlet marginal prickles much wider at base, fused to form a crown |
| var. cupulata |
| 2' Nutlet marginal prickles slightly wider at base, slightly fused, not forming a crown |
| var. redowskii
|