LENTIBULARIACEAE 



Utricularia (Bladderwort) 



Perennial aquatic herbs; plants consisting of stem systems, roots 

 absent; lateral leaf-like branches green, usually bearing bladder-like 

 carnivorous traps, bladders sometimes borne oh separate, non- 

 photosynthetic branches; flowers borne on scapes elevated above 

 water surface, solitary or in racemes; fruit a 2-valved capsule; peren- 

 nating by winter buds (turions). 



Key to Species 



1. Plants floating in the water or creeping over surface of substrate 

 (sometimes appearing anchored). 



2. Plants with two distinct types of branches, green leaf-like 

 branches lacking bladders, and bladder-bearing branches lack- 

 ing chlorophyll, sometimes appearing anchored in substrate 

 (figs. 1A,2A). 



3. Segments of leaf-like branches fine, becoming narrower with 



each dichotomy, ultimate segments thread-like, not toothed 



(fig. IB); corolla pale-yellow to greenish-yellow, lower and 



upper lips nearly equal (fig. lA). 



I. U. fibrosa 



3. Segments of leaf-like branches distinctly flat, segments 

 remaining approximately the same width, divisions minutely 

 toothed (fig. 2B); corolla bright yellow, lower lip nearly twice 

 as long as upper lip (fig. 2A). 



2. U. intermedia 



2. Plants with branches all alike, leaf-like, bearing bladders. 



4. Flowering scapes subtended by a whorl of inflated branches, 

 floats holding the flowers above the water surface (fig. 3A). 



3. U. radiata 



4. Flowering scapes not subtended by inflated branches (floats). 

 5. Leaf-like branches all whorled (fig. 4F); bladders borne at 

 tips of branches (fig. 4F); flowers purple (rarely albino). 



A. U. purpurea 



5. Leaf-like branches chiefly alternate; bladders borne scat- 

 tered on branches; flowers yellow. 



6. Leaf-like segmens flat; spur of corolla very short, sac- 

 cate, almost absent. 



^. U. minor 



6. Leaf-like segments terete; spur of corolla.3 mm or more 

 long. 



7. Leaf-like branches divided 6 or more times; free- 

 floating; plants large, stout, 30-100 cm long. 



