MENTZELIA FAMILY 209 



(2) Spines 1-8, not greatly unlike in length 



(a) Spines twisted, 3-5 O. tortispina 



(b) Spines not twisted, 1-8 



x. Spines 1-3, brownish; joints round to 



obovate O. camdnchica 



y. Spines 5-7; joints oblong '. schwerinidna 



b. Fruit dry, usually spiny ; flowers yellow or red 



(1) Flowers yellow, spines 8-15 O. polyacdntha 



(2) Flowers red; spines 2-4 O.rhoddntha 



2. Joints of the stem flattish to somewhat terete, 



separating easily 



a. Flowers yellowish; joints 1-2 in. long; spines 



usually 4 O. frdgilis 



b. Flowers pink or reddish; joints 2-4 in. long; 



spines 3-5 O. rutila 



3. Joints long, cylindric or angled; stems 2-15 ft. 



high 



a. Plants spreading, about 2 ft. high; edges of 



stem not comb-like O. Ddvisii 



b. Plants erect, 4-15 ft. high; edges of the stem 



comb-like O. arbor esc ens 



LOASALES MENTZELIA ORDER 

 LOASACEAE MENTZELIA FAMILY 



Sepals 4-5, united into a long tube, grown to the ovary, petals 4-10 

 on the throat of the calyx, stamens many, inserted with the petals, ovary 

 1 -celled, style entire or 2-3-lobed; flowers solitary or in racemes or cymes, 

 regular, perfect ; herbs with opposite or alternate leaves, usually armed with 

 hooked hairs. 



MENTZELIA Linne 1753 MENTZELIA 



(Named for Mentzel, a German botanist) 



(Touterea E. & W. ; Acrolasia Rydberg) 



PL 31, fig. 14; pi. 32, fig. 5. 



Sepals 5, united into a cylindric or club-shaped calyx, grown to the 

 ovary, petals 5-10, cream-colored to yellow, stamens 20-many, ovary 1- 

 celled, styles 3, somewhat united, capsule opening at the top, seeds often 

 winged; flowers terminal, solitary or in cymes; leaves alternate, entire to 

 pinnatifid; annual or perennial. 



