TEE PLANT-BODY. 67 



(d) Study as examples of trichoma forms: 1, hairs of petunia or 

 verbena; 2, bristles of tickle-grass; 3, prickles of the hop; 4, scales 

 of the buffalo-berry, or elseagnus; 5, glands of the petunia or walnut; 

 6, root-hairs of seedling cabbages, radishes, etc. ; 7, sporangia of com- 

 mon polypody fern; 8, ovules of anemone, buttercup, columbine, 

 bouncing-bet, etc. 



(e) Study for root-forms: 1, roots of seedling cabbages, radishes, 

 etc. ; 2, aerial roots of greenhouse orchids ; 3, parasitic roots of 

 dodder or mistletoe. 



