Anatomie. 423 



silique des Cruciferes, M. Gerber invoque les resultats de ses 

 observations sur la structure de l'ovaire du Zilla inacroptera. Dans 

 cette Crucifere, les faisceaux inverses n'ont aucun rapport avec 

 les faisceaux placentaires; ils proviennent de ramifications des 

 faisceaux valvaires, lesquelles se deplacent et tournent de 180° 

 sur leur axe pour se ranger et se fusionner en face des faisceaux 

 placentaires. En outre le faisceau inverse ainsi forme n'alimente 

 pas l'ovule qui refoit son faisceau du faisceau placentaire normal. 



C. Queva (Dyon.) 



Holm, Theo, Bartonia Muehl. An anatomical study. (Ann. ot 

 Botany XX. p. 441—448. Plates 23-24. Octbr. 1906.) 



The small genus Bartonia {Gentianeae) is in regard to the floral 

 structure very distinct from Obolaria by lacking nectaries. Both 

 genera, however, are hemisaprophytic; the roots are mycorhizae, but 

 Chlorophyll is present in the stems and leaves. The leaves in Bar- 

 tonia are very small, and scale-like; they are isolateral, since stomata 

 occur on both faces, and since the chlorenchyma represents a 

 homogeneous tissue of roundish cells. There is only one vein, the 

 mediane, and this contains a Single mestome-strand destitute of 

 parenchyma-sheath and stereomatic support. Glandulär hairs of the 

 same structure as those observed in Obolaria occur at the base of 

 the leaves. The stem of Bavtuiiia venia has no mechanical tissues, 

 and a thinwalled endodermis surrounds a stele of several very 

 irregulär mestome-bundles, some being bicollateral, while others are 

 reduced to a few vessels, bordering directly on endodermis. In B. 

 lanceolata the stem shows a firmer structure, there being a conti- 

 nuous ring of thickwalled cells between the leptome and hadrome, 

 thus forming a protective sheath around the hadrome-cylinder. 

 Morphologically the cells of this sheath may be defined as|„mestome- 

 parenchyma." Theo Holm. 



Holm, Theo, RiielUa and Dianthera. An anatomical study. 

 (Bot. Gazette. XLIII. p. 308—329. Plates XI-XII. May 1907.) 



In Ruellia ciliosa Pursh the stem shows the ordinary monostelic 

 structure, while in Dianthera Americana L. we meet with a pol3^stelic 

 axis. Otherwise these plants were found to possess the principal 

 characteristics of the Acauthaceae viz. the cystoliths, the raphidines, 

 the various crystals of calcium Oxalate, the type of stomata, the 

 glandulär and simple hairs, etc. The external structure of the rhizome 

 is described; the presence of additional rootshoots in Ruellia; finally 

 the internal structure of the vegetative organs. In Dianthera the 

 polystely is very plainly observable in the rhizome with the stolons 

 and in the ascending aerial shoots, but not in the long, naked 

 internode which bears the flowers; in this internode the structure 

 is simply monostelic. The number of steles is generally seven, six 

 peripheral and one central; each stele consists of several collateral 

 mestome-strands, arranged in an arch toward the periphery of the 

 stem, while the inner face of the stele is occupied by a pith and a 

 few seattered Strands of pure leptome. All the steles are orbicular 

 in transverse sections and each stele has a thinwalled, completely 

 closed endodermis. Poh'stel}' among the Dicotyledones is, as we 

 remember, only known from Auricula, Giinnera, Nymphaea and 

 Pinguiaila. This structure was, moreover, observed in Dianthera 



