536 Pontederacew—Pontederia. 
1. P. cordéta (fig. 259). Pickercl-weed.—A common North 
American plant, 1 to 2 feet high, desiable for the hardy 
4 aquarium. P. angustifolia is a variety 
with narrow lanceolate leaves cordate 
at the base, and also smaller bright 
blue flowers. 
These plants should be placed in 2 or 3 
feet of water, or they will not bear our 
winters. 
Oxper XV.-COMMELYNACEZ. 
Herbs with linear or lanceolate flat 
usually sheathing leaves and_ solitary 
spicate or umbellate flowers. Perianth- 
segments 6, the outer 3 herbaceous, inner 
petaloid. Stamens 6 or fewer. Fruit a 
2- or 3-celled few-seeded dehiscent cap- 
sule. There are about 20 genera and 
250 species, with the exception of those 
enumerated below, nearly all tropical. 
1, TRADESCANTIA. 
Herbaceous tufted or creeping plants. 
a Stem branched, fleshy, 1 to 2 feet high. 
Fig. 259. Pontederia cordata, : : 
(F nat. size.) Leaves entire, linear-lanceolate,sheathiny, 
glabrous. Flowers in terminal sessile or 
stalked umbels. Perianth 6-parted, the 3 exterior sepaloid, 
and the 3 interior petaloid. Filaments bearded. An Ame- 
rican genus, named in remembrance of Tradescant, gardener to 
Charles I. 
1. T. Virginica. Spiderwort.—A very pretty and interesting 
plant growing about a foot and a half high, with linear-lan- 
ceolate acuminate glabrous ciliate sheathing leaves and sessile 
bracteate umbels. Outer perianth-segments green, inner rosy- 
purple. Filaments densely bearded with long spreading jointed 
purple hairs. There are several varieties, including one with 
white petals and purple filaments, another with beautiful rose- 
coloured petals, and also a double-flowered varicty. 
2. 7. rdsea.—A similar though smaller and less hardy plant, 
