536 Floristik, Geographie, S) r stematik etc. 



Holm, T., Nvssa sylvatica Mursh. (American Midland Naturalist. 

 I. p. 1—12. fig. 1—15. Dec. 1909.) 



At present Nyssa is confined to North America, where three 

 species are distinguished, and to southern Asia, where a Single 

 species is distributed from the eastern Himalayas to the island 

 of Java. The germination and anatomy of Nyssa sylvatica is descri- 

 bed and figured. The seedling has a long primary root with several 

 ramifications, an erect hypocotyl, and two green cotyledons, oblong, 

 and approximately five-nerved. During the first season the foliage 

 of the primary shoot differs in a marked degree from that of the 

 mature tree, since several of the leaves are frequently obovate with 

 the margins dentate, thus resembling the typical leaves of Nyssa 

 aquatica. This leaf-form with dentate margins is, furthermore, com- 

 mon on young shrubs, but ceases when it becomes a tree. 



The primary root of the seedling shows a very simple structure, 

 there being no exodermis, and the cortex being homogeneous thin- 

 walled with no sterei'ds; when the increase in thickness takes place, 

 the cortex collapses, and a pericambial cork and secondary cortex 

 become developed, interspersed with sclereids, and containing starch 

 and aggregated crystals of calcium Oxalate. 



In the hypocotyl a thinwalled endodermis was observed, and a 

 few strata of stereome, pericyclic, may be found near the apex 

 but only outside primary leptome-strands; the increase in thickness 

 is effected by the development of an interfascicular cambium. A some 

 what modified structure occurs in the first internode of the seedling 

 where hypodermal collenchyma was noticed, but no endodermis 

 and where the pericycle appears as an interrupted sheath of typical 

 stereome. In the branches of the tree a cork of numerous, thickwal 

 led strata Covers the cortex, which is now collenchymatic throughout 

 and rieh in Chlorophyll. The pericycle consists here of both stere'ids 

 and sclereids in a closed sheath. Scalariform vessels oeeur in the 

 secondary hadrome beside porous tracheids with bordered pits, and 

 much thickwalled libriform. The pith is heterogeneous, starch-bearing 

 and active in the periphery, but empty in the centre. 



It is interesting to see the difference in structure that exists, 

 if we compare the foliage of the seedling (incl. the cotyledons) with 

 that of the mature tree. In the former the midrib contains only a 

 Single mestome-strand, and the petiole has the mestome-strands 

 arranged in a plane. In the leaf of the mature tree the midrib con- 

 tains two separate mestome-strands which turn their leptome towards 

 the outer face of the blade, thus the hadrome appears in the centre; 

 furthermore in the petiole of the mature leaf the six mestome-bundles 

 form a stele. Otherwise the leaf (of the tree) is bifacial, hairy with 

 small glandulär, and very long pointed hairs. The chlorenchyma 

 contains numerous idioblasts, which are very thickwalled, porous 

 and representing the so-called sclereids. Theo Holm. 



Jones, M. E., Contributions to western Botany. n°. 13. 

 (Salt Lake City, Utah: The author. Jan. 20, 1910.) 



An oetavo pamphlet of 87 pages, oecupied with „New species 

 and notes"; „Mr. Rose and the Umbelliferae"; „Western American 

 birches, by B. T. Butler"; „Nyctaginaceae, by Standle}'"; „Forest 

 trees of the United States, by N. L. Britton"; „Gray's Manual, 

 seventh edition"; „Mr. Heller and nomsnclature"; „Flora of 



