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Show 396 UTRICULARIA NEGLECTA. CHAP. XVII. on Utrieularia vulgaris has appeared; * and it has been no small satisfaction to me to :find that my account agrees almost completely wit~ that of th~s ~istinguished observer. I will pubhsh my descnpt1on. as it stood before reading that by Prof. Cohn, add1ng occasionally some statements on his authority. Fro. 17. ( Utricula1·ia neglecta.) Branch with the divided leaves bearing bladders; about twice enlarged. Utrieularia negleeta.-The general appearance of a branch (about twice enlarged), with the pinnati:fid leaves bearing bladders, is represented in the above sketch (:fig. 17). The leaves continually bifurcate, so ~hat a full-grown one terminates in from twenty to thuty * 'Beitrage zur Biologie der Pflanzen,' drittes Heft, 1875. CHAP. XVII. STRUCTURE OF THE BLADDER. 397 po~nts. Each p~int is tipped by a short, straight bnstle ; and shght notches on the sides of the leaves bear similar bristles. On both surfaces there are many small papillre, crowned with two hemispherical cells in close contact. The plants float near the surface of the water, and are quite destitute of roots, even d tuing the earliest period of growth.* They com1nonly inhabit, as more than one observer has remarked to me, remarkably foul ditches. The bladders offer the chief point of interest. There are often two or three on the same divided leaf genei·ally near the base; though I have seen a single' one growing from the stem. They are supported on short foots talks. When fully grown, they are nearly +o- of an inch (2· 54 mm.) in length. They are translucent, of a green colour, and the walls are formed of two layers of cells. The exterior cells are polygonal and rather large; but at many of the points where the angles meet, there are smaller rounded cells. These latter support short conical projections, surmounted by two hemispherical cells in .such close apposition that they appear united; but they often separate a little when immersed in certain fluids. The papillce thus formed are exactly like those on the surfaces of the leaves. Those on the same bladder vary much in size ; and there are a few, especially on very young bladders, which have an elliptical instead of a circular outline. The two terminal cells are transparent, but must hold much matter in solution, judging from the quantity coagulated by prolonged in1mersion in alcohol or ether. * I infer that this is the case f~om a drawing of a seedling given by Dr. Warming in his paper, '' Bidrag til Kundskaben om Lentibulariacere," from the 'Videnskabelige Meddelelser,' Copenhagen, 1874, Nos. 3-7, pp. 33-58. |
