664 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



showing annular or spiral thickenings or simple pores associated with 

 narrow wood fibers, the walls of the latter being rather thin, more or 

 less lignified and porous; fragments of epidermis of leaf with elliptical 

 stomata, 0.025 mm. in length, and usually with 3 or 4 neighboring 

 cells; pollen grains nearly spheroidal, 0.015 to 0.030 mm. in diam- 

 eter; seeds strongly reticulate, the seed-coat composed of yellowish- 

 brown, polygonal cells, having thick walls; fragments of branched 

 laticiferous ducts having a granular content. 



Constituents. An amorphous, acrid, emetic alkaloid lobeline, 

 which decomposes readily on heating, and is contained in greatest 

 amount in the seeds; a non-acrid but pungent volatile oil, lobelianin; 

 a colorless, tasteless, crystalline, neutral principle inflatin, which is 

 intimately associated with the alkaloid; and lobelic acid, which is 

 combined with the alkaloid lobeline. Lobelacrin is regarded as the 

 lobelate of lobeline. The seeds contain in addition a fixed oil, which 

 when pure is bland, non-acrid and somewhat resembles that of lin- 

 seed. The oil usually seen on the market is of a greenish color and 

 quite acrid and is said to contain all the active principles of the drug. 



Allied Plants. Red lobelia or Cardinal flower, Lobelia cardinalis, 

 and blue lobelia, L. syphilitica, as well as a large number of other 

 species of Lobelia, are used to some extent in medicine. Lobelia 

 nicotiansefolia of India and Delissea acuminata of the Hawaiian 

 Islands have properties similar to Lobelia inflata. 



Adulterants. The seeds of mullein (Verbascum Thapsus) are 

 commonly used as an adulterant of Lobelia seeds, but are distin- 

 guished from them by not being reticulate. 



COMPOSITE, OR COMPOSITE FAMILY 



The largest family of phaenogamous plants, comprising probably 

 more than 10,000 plants, which are very widely distributed. They 

 are distinguished from all other plants in that the inflorescence is a 

 head or capitulum (Fig. 296), consisting of one or two kinds of 

 flowers, arranged on a common torus, and subtended by a number 

 of bracts, forming an involucre. The flowers are epigynous and the 

 fruit is an achene, usually surmounted by the persistent calyx, which 

 consists of hairs, bristles, teeth or scales, which are known collectively 

 as the pappus (Fig. 294). 



The individual flowers are called florets (Figs. 293 to 295), and 

 may be hermaphrodite or pistillate, monoecious, direcious, or neutral. 

 Depending upon the shape of the corolla, two kinds of flowers are 

 recognized, one in which the corolla forms a tube, which is 5-lobed 



