ITS KINDS. 



295 



compound ovary, and even when invested with an adnate calyx- 

 tube. Of the latter is the fruit of Compositae. (Fig. 630-635.) 

 Here the tube of the calyx is incorpo- 

 rated with the surface of the ovary ; 

 and its limb or border, obsolete in some 

 cases (Fig. 630), in others appears 

 as a crown or cup (Fig. 631), or set of 

 teeth or of scales (Fig. 632, 633), or as 

 a tuft of bristles or hairs (Fig. 634, 



635), &c., called the PAPPUS. In the Lettuce and Dandelion 

 (Fig. 635), the achenium is rostrate, or beaked, i. e. its summit 

 is extended into a slender beak. An akene with adnate ealyx 

 has been termed a CYPSELA. 



565. The Utricle is the same as the akene, only with a thin 

 and bladdery loose pericarp, like that of Goosefoot. 



(Fig. 636.) This thin coat sometimes bursts irregu- 

 larly, discharging the seed. In the true Amaranths, 

 the utricle opens by a circular line, and the upper 

 part falls as a rid, converting the fruit into a small 

 pyxis (560), a transition form. (Fig. 637.) 



566. A Caryopsis or Grain differs from the utricle 

 or akene in having the seed completely filling the 

 cell, and its thin coat firml}- consolidated throughout 

 with the very thin pericarp ; as in wheat, Indian 

 corn, and all other cereal grains. Of all fruits this 

 is the kind most likely to be mistaken for a seed. 



567. A Nut is a hard, one-celled and one-seeded, indehiscent 

 fruit, like an achenium, but larger, and usually produced from 

 an ovary of two or more cells with one or more ovules in each, 

 all but a single ovule and cell having disappeared during its 

 growth (536) ; as in the Hazel, Beech, Oak (Fig. 638), Chest- 



FIG. 630. Achenium of Mayweed (no pappus). 631. That of Cichory (its pappus a 

 shallow cup). 632. Of Sunflower (pappus of two deciduous scales'). 633. OfSneezeweed 

 (Helenium), with its pappus of five scales. 634. Of Sow-Thistle, with its pappus of 

 delicate downy hairs. 635. Of the Dandelion, tapering below the pappus into a 

 long beak. 



FIG. 636. Utricle of Chenopodium album , or common Goosefoot. ft!?. Utricle of an 

 Amaranth, by transverse dehiscence becoming a pyxis. 



