ANGIOSPERM^E 



185 



complicated, is found in a number of aquatic forms 

 allied to Naias, and also occurs in some of the terrestrial 

 types among the aroids. In the latter (Fig. 45, A-C), 

 while the individual flowers are often of the simplest 



FIG. 45 (Lower MonocotyledonsV 'A, female inflorescence of the Indian 

 turnip tArisaema), the enveloping bract cut away at the base to show 

 the inconspicuous flowers, fl ; B, a single flower cut longitudinally to 

 show the ovules, o : st, the papillate stigma ; C, a group of male flowers, 

 each consisting of four stamens ; D, two plants of duckweed (Lemna), 

 a minute floating aroid ; tf, the inflorescence consisting of two male and 

 one female flower ; E, the female flower cut longitudinally; F,the male 

 flower, consisting of a single stamen ; G, longitudinal section of the em- 

 bryo of Xaias, showing the characters of the typical monocotyledonous 

 embryo; the cotyledon is terminal, and the stem-apex, st, of lateral 

 origin ; r, the root ; sus, suspensor ; H, male flower of arrow r -head 

 (Sagittaria), consisting of a group of stamens surrounded by three 

 white petals, p, and three sepals, s ; I, section through the head of 

 separate carpels, car, from the female flower ; J, inflorescence (spike- 

 let) of a grass (Dactylis) ; the lowest flower has the three stamens, and 

 the two feathery stigmas protruding ; K, a separate flower of Dactylis, 

 consisting of a single carpel and three stamens in the axil of the bract, 

 p; at the base of the carpel are the two small bracts (lodicules), /. 



description, they are usually aggregated to form a com- 

 pact, elongated inflorescence, the spadix, which may 

 reach a large size and be very conspicuous, especially 

 when, as often happens, it is surrounded by a showy 

 bract, as in the common "calla lily" or some species of 



