634 



MANUAL OF POISONOUS PLANTS 



Dr. White, in his Dermatitis Venenata as saying: "Mentzelia has grown in our 

 garden, and has always been amazingly irritating to us all. Some species are 

 even said to have stinging hairs." The writer has had considerable experience in 

 collecting these species in the West, and he has learned from experience that 

 the barbed hairs are quite irritating. Dr. Halsted states that M. oligosperma 

 has the same properties. This plant is frequently cultivated. 



OPUNTIALES. 



Fleshy plants, usually spiny with jointed stems; leaves small; flowers mostly- 

 solitary, regular ; calyx tube adnate to the ovary with a many lobed limb ; sta- 

 mens numerous, inserted -on the throat of the calyx; filaments filiform; ovary 

 1-celled; ovules numerous; fruit a berry. Contains the important family Cac- 

 taceae. 



Fig. 357. Showy Mentzelia (Ment- 

 selia ornata). The hispid hairs of 

 this plant produce mechanical injur- 

 ies. (Charlotte M. King.) 



CACTACEAE. Cactus Family. 



Fleshy plants, leafless or with small leaves; stems flattened, columnar or 

 globular, generally abundantly spiny; flowers solitary, sessile, perfect; calyx 

 tube adnate to the ovary, limb many lobed; petals numerous, imbricated in 

 several rows, mostly distinct; ovary 1-celled; ovules numerous, anatropous, borne 

 on several parietal placentae; fruit a 1-celled berry or a dry fruit; endosperm 

 wanting or copious. 



