274 Morphologie, Teratologie, Befruchtung, Cytologie. 



Other cytological observations are discussed : a. o. the possibility 

 of development of embryoless fruit, when the embryosac sooner 

 or later completely degenerates. Thus Aucuba japonica would be 

 added to the list of plants, capable of forming parthenocarpic fruits. 

 The original opinion about the apogamy in Aucuba will have been 

 the result of the presence of male inflorescences upon female plants, 

 as is repeatedly found by the writers; the reversed case may also 

 happen sometimes, as Lombard-Dumas reports male individuals 

 now and then producing female flowers. 



M. J. Sirks (Wageningen). 



Schacke, M. A., A chromosome difference between the 

 sexes of Sphaerocarpus texanus. (Science. N. S. IL. p. 218 — 219. 

 Feb. 28, 1919.) 



The female gametophyte nucleus contains a larger, and the 

 male gametophyte nucleus a smaller chromosome than usual, as in 

 5. Donnellii. Trelease. 



Warming, E., Om Jordudlöbere. [Underground runners]. 

 (Mem. Acad. roy. sc. et lettres de Danemark. Sect. Sc. 8me serie. 

 II. N° 6. p. 295 — 378, with 43 text figs., and an english resume. 

 Köbenhavn 1918.) 



As stolons are named plagiotropic overground root-forming 

 shoots with elongated internodes and foliage-leaves. Distinct from 

 these should suboles be kept; they are pale and slender Under- 

 ground runners with elongated internodes and scale leaves. The 

 term rhizome should be restricted to denote Underground plagio- 

 tropic shoots with short internodes, rieh in nutritive matter and 

 therefore thick. The name rhizodes is suggested for such plagio- 

 tropic Underground shoots which have elongated internodes but are 

 like rhizomes therein that the lateral shoots arise from main buds 

 situate in the axil of a particular leaf which is often numerically 

 definable. (Ex.: Hippuris vulgaris, Heleocharis palustris). — Distinct 

 from the above types whose plagiotropic shoots are from orthotro- 

 pic aerial shoots, are those where the main stem bearing foliage 

 leaves is plagiotropic. The} T are either overground creepers or 

 Underground leaf bearing suboles or rhizomes (Ex. Pteridium aqui- 

 linum). — Erect short-stems lying in or near the soil-surface have 

 been named vertical rhizomes, pseudorhizomes, or radix multieeps; 

 they are surviving basal parts of erect aerial shoots. The author 

 terms them mesocormus. 



The paper contains morphological descriptions of a series of 

 soboliferous plants, mostly of northern origin. The general part 

 gives a comprehension of the bioJogical aspects and of the authors 

 views; some of the items are mentioned below. 



The length of the internodes is dependent on the resistance 

 and the moisture of the soil. The longest soboles being found in 

 sandy soil, moist forest mould, field and garden soil, and mud. — 

 The different waA's of piercing through the soil are discussed, and 

 the different shape of the curving section of the runners described. — 

 The author has brought together a quantity of observations concern- 

 ing the depth in which different species keep their runners. The 

 result is that it is extremely difficult to determine a normal soil 

 level for the species, many factors coming in and modifying the 

 result. Thus, a law of level for each species cannot be given yet. 



