sect, ii PHANEROGAMIA 487 



of which the one corresponding to the labellum is developed as a small misshapen 

 hood. Many species are cultivated in conservatories, chiefly for the sake of their 

 bright-coloured foliage. 



Geographical Distkibution. — The Marantaceae grow principally in the 

 tropical regions of America. 



Officinal. — The rhizome of Maranta arundinacea ("West Indies) yields arrow- 

 root, Amylum Marantae. 



Order 7. Gynandrae 



Flowers EPIGYNOUS, hermaphrodite, ZYGOMORPHIC ; perigone 

 corollaceous ; andrcecium reduced to the three anterior 

 members, consisting usually of one fertile stamen and two staminodia, 



ADHERENT TO THE STYLE AND FORMING A COLUMN; ovary usually 



unilocular, with parietal placentation ; fruit, a capsule ; seeds ex- 

 ceedingly numerous AND small, without albumen ; embryo UN- 



SEGMENTED. 



Family Orehidaeeae. — Characteristics the same as for the order 

 (Figs. 431-436). 



The Orchids are all herbs ; they vary greatly in external appear- 

 ance and have racemose, usually spike-like inflorescences. The flowers 

 are almost always pollinated by insects, and to 

 this end have developed the most complicated 

 contrivances. The corollaceous perigone ex- 

 hibits endless variation. The posterior leaf 

 of the inner whorl is often especially charac- 

 terised by its size, form, and colour ; like 

 the similar but not homologous staminodial 

 organ of the Zingiberaceae, it is termed a 

 labellum ; it is frequently drawn out below 



. i -, ■, /TTi- jot Fig. 431.— Orefcidaoeae. Floral 



into a sac-shaped cavity or spur (Fig. 432, diagram (0 , rMs) 



a, / ). In its rudimentary condition the 



labellum is uppermost, but, as a rule, it acquires ultimately an 

 anterior position in consequence of the torsion of 180° suffered by 

 the inferior ovary, or as a result of the tilting over of the whole 

 flower. In the andrcecium only the anterior stamen of the outer 

 whorl and the two lateral members of the inner whorl are developed ;. 

 these two lateral members are usually transformed into sterile, lobed, 

 or tooth-like prominences (b, p), while the central stamen alone is fertile 

 and bears an anther (e.g. Orchis) ; less frequently, the central of the 

 three staminal members of the andrcecium is sterile, while the two 

 lateral are fertile (Oypripedium, Lady's Slipper). The gynostemium (b) 

 formed by the union of the stamens with the tips of the carpels is 

 sometimes developed as a column; sometimes, as in Orchis, it is short 

 and barely elevated above the receptacle. It bears at its apex the 

 stigma and the anther, or a pair of anthers as the case may be. The 

 pollen is rarely powdery, consisting of separate grains (e.g. Oypripedium). 



