532 BOTANY OF CROP PLANTS 



Fruit. — The umbelliferous /rwi/ (Fig. 218) is very charac- 

 teristic. It is termed a schizocarp, i.e., a dry fruit of two 

 carpels, these separating at maturity along the midline or 

 commissure into two one-seeded halves — the mericarps. 

 Each individual carpel or mericarp is indehiscent. The two 

 mericarps remain attached for a while after splitting by a 

 forked stalk, the carpophore (Fig. 218, E). At the summit of 

 the fruit is a swollen nectary, the siylopodium, giving rise 

 to two short, persistent, usually outwardly curved styles. 

 Each mericarp bears, on the outside, five longitudinal mem- 

 branous or corky ribs, the primary ribs. These are modifi- 

 cations of the pericarp; each encloses vascular bundles. In 

 some cases, there is one secondary rib in each of the four 

 furrows or grooves between the primary ones, thus making in 

 many instances nine ribs (five primary, four secondary) to 

 each half of the mature fruit. Within the grooves, as is 

 best seen by a cross-section of a mericarp (Fig. 218, F), are oil 

 tubes (vittae), running lengthwise of the fruit. These tubes 

 contain secretions of balsams, resins, and volatile oils, which 

 impart to the fruit its characteristic odor and taste. The 

 fruit may be bristly (as in carrot) or smooth (as in parsnip, 

 and many others). The bristles may cover the fruit (as in 

 Sanicula), or be confined to the ribs (as in carrot). Oil 

 tubes are sometimes obsolete or obscure (as in Conium, 

 Hydrocotyle, Washingtonia). If distinct, they are solitary 

 (as in parsnip) or several (as in Angelica, Cymopterus). 

 There are usually two or more oil tubes on the commissural 

 side, that is, on the side that is contiguous with the adjoining 

 mericarp. 



The fruit is either flattened laterally (at right angles to the 

 commissure), or flattened dor sally (parallel to the commis- 

 sure), or in some instances not flattened at all (terete or 

 nearly so). The one seed in each carpel completely fills the 



