ITS KINDS. 



295 





compound ovary, and even when invested with an adnate 

 tube. Of the latter is the fruit of Composite. (Fig. 630 

 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, 



calyx- 

 -635.) 



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 lid, 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 firmly 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 liazel, 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. Of Sneezeweed 

 (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. 637. Utricle of an 

 Amaranth, by transverse dehiscence becoming a pyxis. 



