GEOUP IV. PHANEROGAMIA : ANGIOSPERM2B ; MONOCOTYLEDONES. 541 



diclinous, without a perianth : stamens usually connate : leaves generally 

 parallel-veined. Zantedetchia (Calla or Richardia) cetliiopica, with a white 

 spathe, is commonly cultivated under the name of the Trumpet Lily. 



Fam. 6. Colocasioidece : with a net- work of laticiferous vessels : flowers 

 diclinous, mostly without a perianth ; stamens connate : leaves with reticulate 

 venation. The genera Alocasia, Colocasia, and Caladium, are commonly culti- 

 vated as foliage-plants. 



Fam. 7. Aroidece : with straight rows of laticiferous cells : flowers diclinous: 

 usually without perianth. Arum maculatum, the Cuckoo-pint or Lords and 

 Ladies, is a British plant, common in wood and hedges ; the large green spathe 

 completely envelopes the spadix (Fig. 349). Dracunculus and Arisarum are 

 also European genera. 



Fam. 8. Pistioidea: no laticiferous tissue: flowers diclinous, without 

 perianth : microsporangiate flowers numerous and whorled, macrosporangiate 

 flower single, on the spadix. 



Pixtia Stratiotes, a tropical water-plant, is characterized by having the flowers 

 on the spadix reduced to two, one <J flower, and one 9 flower consisting of a 

 single carpel : the spadix and spathe are adherent. It appears highly pro- 

 bable that the Lemnaceae. mentioned below, are in 

 fact very simple forms of this family. 



Order 2. LEMNACB^E. Stem leafless. jl 

 Each inflorescence consists of two $ flowers 

 and one ? flower borne on a lateral branch 

 of the stem : the $ flowers consist of a 

 single stamen, and the $ flower of one 

 carpel. 



Lemna trisulca, L. (Spirodela) polyrldza, minor 

 and gibbet, are known as Duck- weed ; they are FIG. 350. Part of a plant 



common in tanks and ponds, floating on the water. of Lemnn Msulca ' seen from 

 m . , . , . . above : a the young lateral 



The stem, which is leafless, is almost flat, re- brancheg (nafc . size) . 



sembling a thallus: it bears two rows of branches 



(Fig. 350), as also roots on its under surface which are suspended in the water. 

 Boots are, however, absent in Wolffia arrliiza, which is also devoid of vascular 

 bundles ; its flower has no spathe, and it bears only one row of branches : it 

 is the smallest known flowering plant. 



Order 3. PANDANACEJS. Flowers dioecious, perianth : the ? 

 flower sometimes consists of a single carpel; or of several carpels 

 forming a multilocular (species of Pandanus) ovary, each loculus 

 containing a single ovule ; or of several carpels forming a uni- 

 locular (Freycinetia) ovary with numerous parietal ovules; they 

 are closely crowded on the spadix, which becomes a spurious fruit : 

 the ^ flower has numerous stamens: in the genus Freycinetia, 

 each flower usually has rudiments of the missing reproductive 

 organs. 



