546 



BOTANY 



of ovary variable. Limited to tropical and sub-tropical parts of America. The 

 leaves are in rosettes and are typically xerophytic ; in the forms which grow in 

 the soil they are spiny. Ananassa saliva is cultivated and has spread in the 

 wild state in the tropics ; its inflorescence forms the Pineapple. 



Order 6. Seitamineae 



Tropical plants, sometimes of large size, in a few cases arborescent. 

 Flowers dorsiventral or asymmetrical. Perianth differentiated into 

 calyx and corolla. Androecium greatly reduced ; some of the 

 stamens represented by staminodes, and resembling the segments 



of the corolla. Ovary in- 

 ferior, trilocular. Seeds 

 with perisperm. 



Family 1. Musaceae. The 

 Banana (Musa) is one of the 

 most important plants of all 

 tropical countries. The appar- 

 ent, erect stem is formed of the 

 closely overlapping, sheathing 

 bases of the large leaves. In- 

 florescence, terminal. Fruit, a 

 berry. M. textilis yields Manilla 

 Hemp. 

 Fio. 547. Floral diagram of Zingiberaceae (after EICHLER). 



b, Bract ; v, bracteole ; k, calyx ; pi ., segments of corolla; _, .. 



ssti,sst.>, staminodes of the outer whorl of the androecium; .family 2. Zingiber- 



* the suppressed stamen of this whorl ; ft, the singlr aC6ae. Flowers in spikes, 



fertile stamen; I, petaloid staminodes of the inner w hi ch : ,. .- , p 

 whorl of the androecium forming what is known as the 



labeiium. semble capitula. Flower 



dorsiventral. Calyx incon- 

 spicuous, tubular. Corolla with three lobes. Outer whorl of the 

 androecium is wanting or represented by two lateral staminodes 

 (Fig. 547, sst v sst z ). Only the posterior stamen of the inner whorl 

 (st) is fertile; the two others are joined to form the brightly 

 coloured, petaloid labeiium (/). The style lies in the tubular groove 

 between the two thecae of the stamen. Fruit a capsule. Most plants 

 of the family belong to tropical Asia. 



Zingiber officincde, the Ginger, is an ancient cultivated plant of Southern Asia, 

 now cultivated throughout the tropics (Fig. 548). The flattened branched 

 rhizome is in contact with the soil by its narrow side. Leaves, two-ranked ; 

 main shoot continued by the growth of axillary buds of the lower surface. The 

 leafy shoots, in spite of their length, are composed of the sheaths of the large, 

 simple, entire leaves, the axis remaining extremely short. Bracts large and, 

 especially at their margins, brightly coloured. Flowers, bright yellow, with a 

 conspicuous, violet and spotted labeiium. Elettaria Cardamomum and Curcuma 



