T. Holm — Anemonella thalictroides. 247 



an exodermis with very distinct foldings on the radial cell- 

 walls; in other words, the primary root is contractile and at the 

 same time able to store nutritive matters. It is diarch and con- 

 tains a broad central pith. 



In Ficaria ranuncnloides the roots are, also, tuberous, but 

 lack the long, filiform apex observable in Anemonella. More- 

 over, the swelling of the root in Ficaria depends merely upon 

 the presence of a broad primary cortex, while the stele shows 

 only a few secondary vessels at the very base of the root, in 

 the immediate vicinity of the overwintering bud. In Isojpy- 

 rum oiternatum the roots are very different, since they attain 

 a tuberous development in several places on the same root, and 

 very irregularly. 



The flowering stem. 



This represents a long internode terminated by the inflor- 

 escence, and bears only two, opposite involucral leaves. It is 

 cylindric, glabrous and perfectly smooth. The cuticle is thick, 

 and the outer cell-walls of epidermis are moderately thickened. 

 There is no collenchyma, and the cortex consists of three lay- 

 ers with distinct intercellular spaces surrounding a closed 

 sheath of thick-walled stereome of about three strata. The 

 stele contains nine collateral mestome-strands arranged in one 

 circular band, separated from the stereome by a few layers of 

 thin-walled parenchyma. The mestome-strands contain cam- 

 bium between the leptome and hadrome ; the vessels do not 

 show the arrangement in the letter Y as is otherwise quite fre- 

 quently to be observed in this family, A broad, thin-walled 

 pith occupies the central portion of the stele. 



The leaf. 



The long and very thin petiole is cylindric and smooth, and 

 in regard to the internal structure it agrees in most respects 

 with the stem. However, there are only four large and two 

 very small mestome-bundles, and the hadrome shows here the 

 position of the vessels in the shape of the letter Y. But other- 

 wise the structure is identical with that of the stem. The 

 petioles of the leaflets show the same structure, but contain 

 only three mestome-strands. 



The leaf-blade is dorsiventral ; the cuticle is smooth on both 

 faces, and the lateral cell-walls of epidermis are undulate, espe- 

 cially on the lower face. The lumen of epidermis is wider on 

 the dorsal than on the ventral face, and the outer walls are 

 moderately thickened ; the stomata, which are confined to the 

 dorsal face, are surrounded by mostly five, ordinary epidermis- 

 cells ; they are level with epidermis, and the air-chamber is 

 wide, but shallow. The chlorenchyma consists of two layers 



