GROUP V. ANGIOSPERM.E. 



443 



The portion of the floral axis below the flower (i.e. the peduncle 

 or the pedicel) commonly bears one or more bracteoles or prophylla . 

 In most Monocotyledons there is a single posterior prophyllum, 

 whilst in most Dicotyledons there are two lateral prophylla. 



In some cases several bracteoles are arranged in a whorl, forming 

 an epicalyx, either close beneath the flower (as in Malva, Anemone 

 Hcpatica, Dipsacus, or at some distance below it (other species 

 of Anemone). In some plants (Nyctaginaceae) the epicalyx may 

 become an involucre enclosing several flowers ; this is due to the 

 fact that flowers are developed in the axils of some of the bracte- 

 oles of the terminal flower. Though they are generally green, the 

 bracteoles are sometimes brightly coloured, as in some Amarantacese 

 and Nyctaginacese ; or scaly, 

 as the lodicules of Grasses. 



The Flower (p. 55) is a shoot 

 of limited growth, with un- 

 developed or but slightly de- 

 veloped internodes, bearing, as 

 a rule, both perianth-leaves 

 and sporophylls on the some- 

 what shortened and expanded 

 terminal portion of the axis 

 which is the receptacle or 

 torus. 



The perianth -leaves are 

 generally differentiated into 

 two series : an outer, of usually 

 rather small green leaves, the 

 sepals, constituting the calyx : 

 an inner, of usually conspicuous 

 brightly coloured leaves, the 

 petals, constituting the corolla. 



The flower is usually mono- 

 clinpus (hermaphrodite) ; but is 

 not infrequently unisexual, when it is diclinous, or even dioecious. 

 The sporangia, with but few exceptions, are borne upon sporo- 

 phylls (see p. 56) : the microsporophylls (stamens) constitute 

 the andrcecium, the macrosporophylls the yyna:ceum, of the 

 flower. 



It occasionally happens, that one or more of the internodes 

 within the flower may be developed to some extent : for instance, 



PIG. 260. Diagram of an angiospermous 

 flower: Ke calyx; K corolla ; / filament of 

 stamen; a anther with two pollen-sacs in each 

 half which are opened, showing the pollen- 

 grains (p). On the stigma (n) are pollen- 

 grains (p) which have germinated; the 

 pollen-tube (p) penetrates the style (g) as 

 far as the cavity of the ovary (F), reaching 

 the ovule (S) ; t the integument of the ovule ; 

 em the embryo-sac ; E the oosphere. 



