ANGIOSPERMiE 



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 Monocotyledons"). — A, female inflorescence of the Indian 

 turnip (Arissema), 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 ; fl, 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 Naias, 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-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 floiver 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) , I. 



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 



