494 PART III. THE CLASSinCATION OF PLANTS. 



so-called spathe which invests the flower of these plants. On the 

 other hand, some Dicotyledons have a single prophyllum which is, 

 however, always lateral : this is frequently the result of the sup- 

 pression of the second prophyllura, but there are cases (Banuncuhis 

 aquatilis, auricomus, Lirigua) in which this is apparently the normal 

 condition. 



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

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

 Hepatica, Dipsacus, Clasia, Camellia), or at some distance below it 

 (other species of Anemone). In some Nyctaginaceoe 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 Amarantaceae 

 and Nyctaginaceae ; or scaly, as the lodicules of Grrasses, 



The Flower (p. 76) consists of an axis bearing, as a rule, both 

 perianth-leaves and sporophylls on the somewhat shortened and ex- 

 panded 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, consti- 

 tuting the calyx : an inner, of usually conspicuous brightly coloured 

 leaves, the petals, constituting the corolla. 



The flower is usually ambisporangiate (hermaphrodite, mono- 

 clinous), but is not infrequently monosporangiate (unisexual, 

 diclinous, or even dioecious). The sporangia, with but few excep- 

 tions, are borne upon sporophylls (see p. 78) : the microsporophylls 

 (stamens) constitute the androecium, the macrosporophylls the 

 gynoeceum, of the flower. 



The growth of the floral axis terminates with the development 

 of the floral leaves at its apex, excepting in abnormal cases ; and 

 buds are not developed, except in monstrosities, in the axils of 

 these leaves. The characteristic feature of that portion of the 

 floral axis which actually bears the flower is that the internodes 

 between successive floral leaves or w^horls of leaves, are not as a 

 rule developed, so that all the floral leaves are closely packed and 

 are nearly at the same level, the perianth- leaves being external 

 and the sporophylls internal. It occasionally happens, however, 

 that one or more of the internodes within the flower may be deve- 

 loped to some extent : for instance, the internode (termed antlio- 

 phore) between the calyx and the corolla, as in Lychnis and some 

 other Caryophyllaceoe ; that (termed gonophore) between the corolla 



