PERIANTH, OR FLOWER-LEAVES. 243 



SECTION V. THE PERIANTH,* OR CALYX AND COROLLA IN 



PARTICULAR. 



439. The distribution of the floral leaves around the axis, 

 which belongs to phyllotaxy, and their particular disposition in 

 the bud (aestivation), have already been considered in Chap. IV. 

 Sect. I., II. And most of the morpholog}' of cabyx and corolla 

 has been outlined in the preceding sections of the present chap- 

 ter. What remains chiefly relates to particulars of form and 

 to terminology. 



440. Duration. The differences in this respect give rise to a 

 few terms, such as the following. Calyx or corolla may be 



Persistent, not cast off after anthesis, but remaining unwithered 

 until the fruit is formed or matured ; as the calyx in Labiatse, in 

 Physalis, and most Roses. 



Marcescent, withering or drying without falling away ; as the 

 corolla of Heaths, Drosera, &c. 



Deciduous, falling after anthesis and before fructification ; as 

 the petals of Roses, the calyx and corolla of Columbine. 



Ephemeral or Fugacious, lasting for only a day ; as the petals 

 of Poppy, Helianthernum, Purslane, and Spiderwort. In the 

 two former, they are cast or early deciduous, the anthesis lasting 

 but a day : in the two latter, the anthesis is equalby or more 

 brief, but the petals deliquesce or decay at once without falling, 

 as does the whole flower of Cereus grandiflorus and other night- 

 blooming Cactaceas. 



Caducous, falling when the blossom opens ; as the calyx of 

 Poppy and Baneberry. 



441. Numerical Terms, succinctly denoting the number of 

 leaves, either of the perianth as a whole, or of any one of its 

 circles, are common in descriptive botany. The most general 

 are those which simply specify the number of component leaves, 

 by prefixing Greek numerals to the Greek name of leaves, ex- 

 pressing them in Latin form, or transferring them to the Eng- 

 lish. Thus 



Diphyllous, of two leaves (sepals or petals) ; Triphyllous, of 

 three ; Tetrfip/>yllous,offour ; Pentaphylloits. of five ; Hcxaphyllous, 

 of six, and so on. A tulip and a Tradescantia flower have a 

 hexaplryllous perianth, but composed of two circles, answering 

 to calyx and corolla ; each TriphyUous. z When the character 



1 Perianthium, alias Per/i/one or Perigonium. (296.) 



2 As elsewhere explained, when numerical composition is indicated without 

 reference to nature of parts, the terms dimerous, trirncrous, tetramerous, penta- 

 merous, &c., may be used. (322.) 



