PASSION FLOWER 451 



Powder. Yellowish-green; non-glandular hairs numerous, from 

 0.500 to 0.800 mm. in length and from 0.020 to 0.030 mm. in width, 

 having at the base small lumina and often being curved, so that the 

 major portion of the hair lies somewhat parallel to the surface of the 

 stem or leaf; fragments of the epidermis from the stems composed of 

 somewhat rectangular cells attaining a length of 0.070 mm. and a 

 few broadly elliptical stomata, about 0.030 mm. in length; sub- 

 epidermal cells from the stems resembling those of the epidermis in 

 shape but with lignified walls; tracheae, spiral attaining a width about 

 0.020 mm., and having bordered pores; tracheids from stems and 

 strongly lignified thick-walled selerenchyma, few; lignified pith 

 parenchyma with large simple pores; numerous fragments consisting 

 of the epidermal cells and mesophyll of the leaf, the former with 

 somewhat wavy vertical walls and associated with stomata attaining 

 a length of 0.024 mm., the cells usually containing green plastids; 

 numerous crystals of calcium oxalate mostly in rosette aggregates 

 from 0.015 to 0.030 mm. in diameter, occasionally in prisms; few 

 simple starch grains from the stem about 0.005 mm. in diameter. 

 (Newcomb.) 



Constituents. Volatile oil from 0.2 to 0.9 per cent; a non- 

 glucosidal bitter principle, 7 per cent; a hard brown resin, 6.39 per 

 cent; a mixture of a soft resin and chlorophyll, 8 per cent; tannic 

 acid, 3.4 per cent; starch, 6 per cent; extractive, 10 per cent; a 

 gummy substance, 13.5' per cent; and protein substances, nearly 

 15 per cent. Ash not more than 10 per cent. 



PASSIFLORACEJE, OR PASSION-FLOWER FAMILY 



The plants are mostly herbaceous or woody vines, and repre- 

 sented by about 325 species. They are most abundant in South 

 America, a few of the species of Passiflora, however, being quite 

 common in the southern United States. Nearly all of the plants 

 have elongated tannin sacs and intercellular secretory canals, with 

 a brownish content. The pericycle consists either of isolated groups 

 of bast fibers or a composite and continuous ring of selerenchyma. 

 The tracheae usually are marked by simple pores, except in the primary 

 wood, when they possess scalariform thickenings. The wood fibers 

 have both simple and bordered pores. Calcium oxalate is secreted 

 in the form of solitary crystals or rosette aggregates. Non-glan- 

 dular hairs are either unicellular or uniseriate, the former usually 

 having a more or less hooked summit. Glandular hairs are usually 

 of a woolly or shaggy type. Large nectarial glands are common to 



