40 Floristik, Geographie, Systematik etc. 



shaped organ. While the primary root dies off at an early stage, 

 the secondary grows out as a very strong root with many kiteral 

 ramifications. Polyembryony was noticed in several instances, but 

 the cotyledons were suppressed entirely. The internal structure 

 shows some points of interest. In the primary root, for instance, no 

 increase in thickness takes place; the cortex contains an oilj^ sub- 

 stance in the cells, while no secretory ducts were observed; the 

 Center of the stele is occupied by a broad pith. The secondarj^ roots 

 show a similar structure, but the leptome contains here wide resini- 

 ferous ducts, each surrounded by a sheath of small, narrow cells. 

 Increase in thickness takes place at an early stage by the develop- 

 ment of cambial' strata inside the leptome and outside the hadrome. 

 The leaf-structure is bifacial in regard to the distribution of stomata 

 on the dorsal face, and the palisade-tissue. The pneumatic tissue is 

 traversed by numerous resiniferous ducts. The midrib consists of 

 two mestome-bundles, a ventral and a dorsal, imperfectly separated 

 from each other by layers of stereome. Of these the dorsal mestome- 

 strand has the leptome situated underneath the hadrome, while in 

 the ventral the leptome occupies the opposite position, thus the two 

 groups of hadrome are actually located in the center of the midrib. 

 In the lateral veins of first order the leptome frequently occurs as 

 separate groups on the sides of the hadrome, rendering the structure 

 hadrocentric; the lateral veins of second order show, on the other 

 hand, a typical collateral structure. Resiniferous ducts were observed 

 in the leptome of all the veins. A collenchymatic tissue of quite 

 considerable size accompanies the mediane and the thicker, lateral 

 veins. The petiole is short and very thick, hemicylindric in outline 

 with two narrow wings. A palisade-tissue Covers both faces, inside 

 of which is a large mass of thickwalled parenchyma with Chlorophyll, 

 and traversed by several wide resiniferous ducts. There is a stele 

 in the center; it is broad and arch-shaped with the ends turned 

 inward. The stele represents several collateral bundles with ducts 

 in the leptome. 



The young internodes of the aerial shoot have a very thickwalled 

 epidermis and a compact cortex. No endodermis is differentiated 

 and the stereome occurs only as small isolated groups outside the 

 leptome of the collateral mestome-strands. The thin walled pith was 

 observed to contain resinous matters in the cells, but ducts were 

 only noticed in the leptome. 



The large tuberous hypocotyl is astelic, and the cortex passes 

 insensibly over into the central pith. The fibrovascular System does 

 not represent a central stele, but two oval bands of mestome-bundles, 

 some of which were regularly collateral, while others approximately 

 hadrocentric. Theo. Holm. 



Ley, A., Hieracium notes. (Journal of Botany. Vol. XLV. N^. 531. 

 p. 108—112. March 29, 1907.) 



The author describes a number of new forms of the genus 

 Hieracium, as well as a few Scandinavian forms recently detected 

 in England. The new forms are as follows: ^. brittanniatm F. J. Hanb. 

 var. nov. ovale; H. ciliatum Almq. var. nov. venosum\ H. serratifrons 

 Almq. var. nov. Cinderella. F. E. Fritsch. 



