FLOEAL ENVELOPES — CALYX. 



197 



the leaves of the calyx stalked. They are usually sessile leaves, in 

 which the laminar portion is only slightly developed, and frequently 

 the vaginal part is alone present. Sepals are generally of a more or 

 less oval, elliptical, or oblong form, with the extremity either blunt or 

 acute. In their direction they are erect or reflexed (with their apices 

 downwards), spreading outwards (divergent or 'patulous), or arched in- 

 wards (connivent). They are usually of a greenish colour, and are 

 called foliaceous or herbaceous ; but sometimes they are coloured, . as 

 in the Fuchsia, Tropseolum, Globe-flower, and Pomegranate, and are 

 then called petaloid. Whatever be its colour, the external envelope of 

 the flower must be considered as the calyx. 



The nature of the hairs on the calyx gives rise to terms similar 

 to those already mentioned as applied to the surfaces of other parts 

 of plants (p. 33). The vascular 

 bundles sometimes have a promi- 

 nent rib (figs. 296, 297), which 

 indicates the middle of the sepal, 

 at other times they have several 

 ribs (fig. 298). Thevenation is use- 

 ful as pointing out the number of 

 leaves which form a gamosepalous 

 calyx. At the part where two 

 sepals unite, there is occasionally 

 a prominent line, formed by the 

 union of the vessels of each (fig. 

 into two branches, each following the course of their respective sepals. 



In a polysepalous calyx, the number of the parts is marked by 

 Greek numerals prefixed. Thus, a trisepalous calyx has three sepals, 

 pentasepalous or pentaphylloiis, five, as in Stellaria Holostea (fig. 293), 

 and so on. The sepals occasionally are of different forms and sizes. 

 In Aconite, one of them is shaped like a helmet, and has been called 

 galeate {galea, a helmet). In Oalcophyllum one of the sepals en- 

 larges after the corolla falls, and assumes a pink colour. In Clero- 

 dendron Thomsonae the white calyx becomes pinkish after the scarlet 

 corolla withers. 



In a gamosepalous calyx the sepals adhere in various ways, some- 

 times very slightly, as in (Enothera ; and their number is marked by 

 the divisions at the apex. These divisions are either simple projections 

 in the form of acute or obtuse teeth (fig. 297) ; or they extend down 

 the calyx as fissures about half-way, the calyx being trifid (three-cleft), 

 quinquefid (five-cleft), as in Primula elatior (fig. 296), according to 

 their number ; or they reach to near the base in the form of partitions, 



Fig. 296. Quinquefid or flve-olett calyx of Primula elatior, the oxlip. Pig. 297. Mve- 

 toothed inflated calyx of Silene inflata. Fig. 298. Calyx, c, of Hitiscns, with its 

 calioulus or epicalyx, 6. 



Fig. 296. Fig. 297. 



Fig. 298. 



298), which divides near the apex 



