MUNOCUTYLEDUNS xVND Dlr( ITYLEDONS 



249 



cies of Iri.s (flags) (Fig. 2;!:.'), Cnwiis, Gladiulti.^ (Figs. 233, 

 2M), etc., the flowers are not only eiDigynous, but some of 

 them are zygomorphic. 

 AVhen a plant has 

 reached both epigyny 

 and zygomorphy in its 

 flowers, it may be re- 

 garded as of high rank. 



130. Orchids.— In 

 number of species this 

 {0 rcli idd (■ e w) is the 

 greatest family among 

 the Monocotyledons, 

 the species being vari- 

 ously estimated from 

 six thousand to ten 

 thousand, representing 

 between one third and 

 one half of all known 

 Monocotyledons. In display of individuals, however, the 

 orchids are not to be compared with the grasses, or even 

 with lilies, for the various species are what are called "rare 

 plants" — that is, not extensively distributed, and often 

 very much restricted. Although there are some beautiful 

 orchids in temperate regions, as species of Huhenaria (rein- 

 orchis) (Fig. 33.5). T'tiijiinid, ('ahi-jKKjinu C'ldjipso, Cypripe- 

 dium (lady-slipper, or moccasin flower) (Fig. 236), etc., 

 by far the greatest display and diversity iire in the tropics, 

 where many of them are brilliantlj- flowered epiphytes 

 (Fig. 237). 



Orchids are the most highly specialized of Monocoty- 

 ledons, and their brilliant coloration and bizarre forms are 

 associated with maryelous adaptation for insect visitation 

 (see Plant Ticlatiou.'^, pp. 134. 135). The flowers are epigy- 

 nons and strongly zygomorphic. One of the petals is re- 

 markably modified^ forming a conspicuous lip which is 



Fiu. 'i?,(). Diagrammatic cross-section of ovary 

 of LUiii/n PliUaddjihicum, showing the three 

 loculi, in each of which are two ovules (mega- 

 sporangia); -I, ovule; B, integuments; (\ nu- 

 celhis ; D, embryo-sac (megaspore).— Cald- 

 well. 



