ANGIOSPERM^: 



379 



B 



the floral axis, and not from the carpel, and this is probably the 

 primitive condition among the Angiosperms. , 



These very simple flowers are commonly crowded into heads or 

 spikes, as in Sparganium, Typha, the Aracese, etc., and are either 

 destitute of any floral envelopes or these are inconspicuous scales. 



A somewhat higher type of flower is found in the Alismacese 

 (Sagittaria, Alisma, etc.). In these (Fig. 355) the flowers may be 

 either diclinous or hermaphrodite, but are furnished with showy 

 petals. The carpels, as well as the other floral leaves, are entirely 

 separate. These apocar- 

 pous Monocotyledons A N ^\^^* D 

 show marked resemblance 

 to some of the lower 

 families of Dicotyledons, 

 notably the Ranunculaceee 

 and Nymphseacese, which 

 may be related to them. 

 The latter family, indeed, 

 has recently been referred 

 to the Monocotyledons. 



The majority of the 

 Monocotyledons have the 

 parts of the flower defi- 

 nite in number, and the 

 flower is usually composed 

 of whorls of three leaves 

 (Fig. 350). The carpels 

 are united into a com- 

 pound pistil, the ovary 

 being divided into three 



chambers, or having a FiG.35l. ErythroniumAmericanum. A, flower 



and leaves. B, bulb (X J). C, pistil (X 1). 

 D, plan of the flower. 



single cavity, with three 

 placentae bearing the 

 ovules upon its wall (Figs. 350, 351). In the simpler types (e.g. 

 Lilium, Trillium, Calochortus, etc.) the perianth is composed of two 

 whorls of entirely free leaves, the outer ones somewhat smaller and 

 sometimes green, two sets of three stamens, and three coherent 

 carpels. When all the parts of the flower are free and inserted 

 below the carpels the flower is " Hypogynous." 



In the Amaryllis family (Fig. 368), to which belong the Narcissus, 

 Crinum, etc., the same arrangement of parts is found, but the peri- 

 anth leaves are coherent, and form a tubular perianth, whose base 

 is coherent with the ovary, which thus lies apparently below the 

 outer parts of the flower. Flowers with an "infejior" ovary are 

 called "Epigynous." 



