There are 11 words that start with 'ligni'.
| lignin | lignify | 
| lignins | lignite | 
| lignites | lignitic | 
| lignified | lignifies | 
| lignifying | lignification | 
| lignifications | |
Note: These 11 words that start with 'ligni' are found from the USA & Canada version of the tournament Scrabble word list.