192 THE FLOWER. 



Clematis and Anemone, Fig. 364) , and the corolla is sometimes 

 greenish or leaf-like, the only real difference between the two is 

 that the calyx represents the outer 

 and the corolla the inner series. 

 Even this distinction becomes arbi- 

 trary when the perianth consists of 

 three or four circles, or of a less 

 definite number of spirally arranged 

 members. 



349. Yet the only perianth obvi- 

 ously present may be corolla, as when 

 the calyx has its tube wholly adnate 

 to the ovary and its border or lobes obsolete or wanting. 1 Aralia 

 nudicaulis (Fig. 341) is an instance, likewise many Umbelliferse, 

 some species of Fedia or Valerianella, the fertile flowers of Nyssa, 

 and those Compositae which have no pappus. For PAPPUS, 

 the name originally given to thistle-down and the like, answers 

 to the border or lobes of a calyx attenuated and depauperated 

 down to mere fibres, bristles, or hairs. The name is ex- 

 tended to other and less obliterated forms. (644, Fig. 631-633.) 

 When the obliteration is complete, as in Mayweed (Fig. 630) , 

 in some species of Coreopsis, &c., the corolla seems to be simply 

 continuous with the apex of the ovary. A comparison with 

 related forms reveals the real state of things. 2 



350. So also in Hippuris, in which (along 

 with extreme numerical reduction of the other 

 floral circles) the calyx as well as corolla seems 

 to be wanting ; but the insertion of the stamen 

 on the ovary (epigynous) suggests an adnate 

 calyx, and near inspection detects its border. 



351. Both calyx and corolla are really want- 

 ing in the otherwise complete and perfect (symmetrical and 



1 In the flowers of the two common species of Prickly Ash (Zanthoxy- 

 lum) of the Atlantic United States, one has a double, the other a single 

 perianth (as shown in Gray, Gen. Illustr. ii. 148, t. 156) : the position of the 

 stamens gives a presumption that the missing circle of the latter is the calyx ; 

 yet it may be otherwise explained. In Santalaceae there are some grounds 

 for suspecting that the simple perianth, although opposite the stamens, is 

 corolla ; and the foliaceous sepal-lobes of the female flowers of Buckleya 

 would confirm this, if these are true sepals rather than adnate bracts. 



2 In the pappus of Compositae, every gradation is seen between undoubted 

 calyx, recognizable as such by structure as well as position, and diaphanous 

 scales, bristles, and mere hairs, wholly " trichomes " as to structure, although 

 in the place of " phyllomes " and representing them. 



PIG. 364. Flower of Anemone Pennsylvania ; apetalous, the calyx petaloH. 

 FIG. 365. Aclilamydeous flower of Lizard'8-tail (Saururus cernuus), magniied. 



