COURSE OF THE BUNDLES IN THE STEM. 377 



concerns us here was briefly stated in 1874': it is the discovery of a new form of 

 bundle system in the /oh'age- or flowering-stems of Lilium, Tulipa, Fritillaria, Cepha- 

 lanthera, Epipactis, and Hedychium. The course of the bundles is such that the 

 bundles of the leaf-trace penetrate downwards, and for different distances inwards to- 

 wards the middle of the stem, and then affix themselves on corresponding bundles 

 of lower leaves, without having previously curved outwards. For the rest we may here 

 refer to Falkenberg's comprehensive work, and print off the above paragraphs with- 

 out alteration as they were written down about four years ago, since they coincide in 

 the main with his work. 



VI. Phanerogams with an Axile Bundle. 



Sect. 72. A number of plants with reduced foliage and roots living in water or 

 marshes, and some in damp humus, belonging partly to the Monocotyledons, partly 

 to the Dicotyledons, show the bundle-system of the stem united into one bundle, 

 which is surrounded by a thick cortex, and traverses the middle of the stem longi- 

 tudinally : from it bundles pass at the nodes into the leaves. With this simplicity of 

 course there . is usually connected a considerable simplification in the structure of 

 the bundles, which always shows peculiarities : we shall return to them in Sects. 105 

 and no. 



As regards the coarser structure, and especially the relations to the bundles 

 of the leaf-trace, which it may be said require more exact study in many cases, 

 there may he distinguished two chief forms. Firstly, axile bundles, formed or 

 developed sympodially from weak bundles of the trace, which approach closely to 

 one another, and coalesce longitudinally : thus they do not differ in their first origin 

 from the typical bundle-systems of the Phanerogams : secondly, such as are cauline, 

 and grow acropetally with the end of the stem ; the bundles which run to the leaves 

 are given off from the former at the nodes, or apply themselves to them as branches : 

 thirdly, those cases in which the axile bundle is built up of longitudinally coalescent 

 bundles of the leaf-trace together with cauline bundles are connected with the two 

 former cases as intermediate forms. 



To the first category belong the following Dicotyledons : BuUiarda aquatica ac- 

 cording to Caspary's account^, Hottonia, Elatine Hydropiper, hexandra, also E. 

 Alsinastrum ', and probably Trapa natans : of Monocotyledons, Potamogeton pectina- 

 tus and pusillus, to which may be added Zanichellia' and Althenia' j also Ruppia" and 

 its allies. To the second category the following Dicotyledons belong : Aldrovandia '', 



* Botan. Zeitg. 1874, p. 732. 



'' Schriften d. Physical, oconom. Gesell. zu Konigsberg, Bd. I. i860. 



' [Comp. Friedrich Miiller, Struktur einiger Arten von Elatine, Flora, 1877, p. 481.] 



* Schleiden, Beitr. p. 215. — Caspary, Pringsheim's Jahrb. pp. 383, 440. 

 ^ PrlUieux, Ann. Sci. Nat. 5 s^r. torn. II. 



" Compare Irmisch, Ueber einige Arten d. Familie d. Potameen (Abhandl. d. Naturwiss. Vereins 

 f. Sachsen und Thiiringen, 1858), p. 44. 



' Caspary, Botan. Zeitg. 1859, p. 126, Taf. V. Ibid. 1862, p. 193. 



