Chapter XIII — 223 — Utricularia, Biovularia 



in no relation to the leaves except that they are usually nearer the 

 nodes than to the middle of the internode, and either in front or 

 behind them. They do not arise in a leaf axil. These, first seen 

 by BucHENAU and thought by him to be roots, are the "tendrils" of 

 Prlngsheim and "air shoots" of Goebel (23 — i). Gluck ques- 

 tions their usefulness as air shoots. They are long and very slender 

 with two lateral rows of "mussel-shaped" leaves with stomata, and 

 are circinate forwards. They are absent from many species, including 

 all of the U. exoleta type. They have the abihty to transform them- 

 selves by apical growth into ordinary shoots (Goebel, Glxjck). 

 (2) Lateral branches (st2) arise near the upper edge of the oblique 

 leaf insertion, but not in the leaf axil. They are of occasional oc- 

 currence only {21 — 8, st2). (3) The inflorescence (sc) arises in as- 

 sociation with a third stolon branch (sta) in the axil of sta, the latter 

 being the larger at first, the scape arising from its base. As Goebel 

 observed in U. flexuosa, "Never does one find the inflorescence iso- 

 lated, but always combined with a leafy branch springing from its 

 base." The question which of the two is primary cannot at the mo- 

 ment be settled. (4) In some leaf axils ("older ones," Pringsheim) 

 buds may arise, which do not center on the middle of the leaf axil. 

 Here again are two, one arising from the base of the other, and they 

 are a leafy shoot and a scape (the smaller) just as when an st2 branch 

 is present, but now in a leaf axil, not in the branch axil {21 — 9). 

 Pringsheim calls them dwarf or aborted shoots. (5) In the axil of 

 most leaves there is a cluster of about 4 traps arising at the middle 

 point. Goebel interpreted Pringsheim's observation and drawing to 

 mean that this group of traps arises from a short branch, while 

 Pringsheim thought that the branch arises from a trap stalk. Goebel 

 is probably correct {21 — 10). 



U. stellaris, U. inflata and the Hke appear to conform to the above 

 description. In U. oligosperma and U. mixta somewhat more special 

 conditions prevail. Instead of one branch of st2 rank, there are two, 

 coordinate in development, one opposite the single leaf (undivided at 

 the base) and one below the axil. The lower of these {U. oligosperma) 

 bears leaves with very many traps, the upper is almost devoid of 

 traps. Above the axil of the upper branch arise the twin branches, 

 one a leafy branch, the other a scape, conjoined at the base {21 — 

 11). Thus in maturity there is a cluster of stolons radiating from 

 the base of an inflorescence, the forward and backward extensions 

 of the chief stolon, and three leafy branches. In both species the 

 air shoots are prominent and have laterally placed at their bases 

 clusters of traps which have been referred to already as dwarf leaves. 

 They occur also at the leaf bases, either axillary or at one side. There 

 is evidence that these are dwarf shoots (Goebel) bearing traps with 

 broadened stalks, not trap stalks bearing shoots, as Pringsheim 

 thought. 



V . minor {21 — 16, 17) was studied by Irmisch and by Buchenau. 

 It is a smaller and more slender plant, the leaves, in lateral rows, be- 

 ing placed aslant, facing upward, the upper edge being therefore farther 

 from the apex than the lower. The branching is essentially as in 

 U. vulgaris, with the difference that the chief branch (st2) arises at 



