PYRETHRI FLORES. INSECT FLOWERS. 



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two- or three-celled pedicle. The glands are elliptical, 

 about six-celled, three rows of two cells each superim- 

 posed. This portion of the flower is rich in vascular 

 elements, spiral annular ducts being numerous. The 

 disk is composed of polygonal, thick- walled, much pitted 



Fig. 57. — Pyrethri Flores. 

 Insect powder: sc. Stone cells; ep, epidermis; h, hairs; ept, epi- 

 dermis with papillae; St, St\ tissue of flowers; ^, vessel; pa, paren- 

 chyma; po, pollen grains; P, cells of pappus; D, glands; 5, portion 

 of flower; ep', epidermis of flower; iep, cells of interior of flower and 

 stems; Fr, stone cells of fruit; rh, rhomboid crystals (Hanausck). 



sclerenchyma. Bracts bearing thick- walled epidermis 

 over keel, thinner toward margins and on inner surface, 

 stomata numerous. Within through a loose parenchyma 

 runs a single fibro-vascular bundle with a dense layer of 

 bast fibers, extending into the margins. The ligulae of 



