Chapter XIII — 225 — Utricularia, Biovularia 



out shoots of two kinds, one chiefly trap-bearing; or (2) on 

 the surface of the wet substrate, sending out branches which pene- 

 trate the substrate, bearing traps and reduced leaves. These emerge 

 eventually. To the former belong such species as U. ochroleuca, U. 

 Bremii (Europe) and U. minor (in both hemispheres). To the latter 

 belongs U. intermedia (20 — 4; 21 — 13, 14). According to Glijck 

 they exhibit a good deal of polymorphism in response to environmental 

 differences. So far as they have been investigated the method of branch- 

 ing shows no peculiarities. For full accounts the reader may be referred 

 to Glijck's book. 



Here may be mentioned the peculiar U. clandestina Nutt. (23 — i). 

 This is a lax floater of the general appearance of an undernourished 

 condition of U. vulgaris. It is provided with special branches with 

 reduced foliage and traps, these occurring sparingly if at all on the 

 leaves of the main stolons. The scape of the inflorescence arises in 

 connection with a branch (the latter in or near the axil of a leaf) 

 and, in addition to the normal inflorescence bearing normal flowers, 

 bears at its base usually two flowers in the axils of scales. The ped- 

 icels of these flowers nod downwardly and produce seed abundantly 

 by close pollination (presumably). Sometimes these cleistogamous 

 flowers (which never emerge from the water) are produced without an 

 accompanying scape bearing proper flowers. The presence of scale 

 leaves allows no doubt that the spur on which they are borne rep- 

 resents an undeveloped inflorescence. Its position with relation to 

 a leaf and branch are the same as above described for a normal in- 

 florescence. 



In this species also air shoots are to be found, usually emerging 

 from the upper surface of the chief axis rather near to an inflores- 

 cence. They are absent from others of this group above cited. 



A few forms are, with the exception of their inflorescences of course, 

 not only completely submersed, but their chief stolons are buried in 

 in the substrate of sand or mud, and their leafy branches or merely 

 their leaves emerge into the supernatant water. Among these may be 

 counted U. resupinata (N. America), U. biloha (Australia) and U. 

 paradoxa (in Ms.) (Angola). 



U. resupinata {23 — 8, 9). — ^ The body of the plant consists of 

 horizontal stolons bearing terete, tapering leaves on the upper surface, 

 with branch stolons emerging laterally, a pair at each node. This 

 is a wide departure from what we have seen above, and foreshadowing 

 what we shall see in the terrestrial forms. The leaves are circinate 

 backwards, that is, away from the apex of the bearing stolon, as 

 first observed by Goebel in U. orbiculata. The inflorescence arises 

 as a bud in the forward leaf axil, flanked usually by stolon buds. 

 From the base of the scape a number of rhizoids spring out and 

 penetrate the substrate. The method of branching is the same in 

 U. hiloha and U. paradoxa {21 — 22), the differences being in their 

 leaves. In the latter they are much as in U. vulgaris but emerge 

 from the substrate and appear as little trees in the water. The 

 traps are borne chiefly on the stolons. In U. hiloha the leaves are 

 articulated, segment with segment {21 — 21). Sometimes a seg- 

 ment becomes a stolon, iUustrating the indeterminate morphological 



