488 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
the preceding and succeeding spring wood. The libriform fibres of the 
spring wood showed, in some case>, five times greater thickness than 
those of the autumn wood ; even the vessels of the spring wood had 
thicker walls than those of the autumn wood. This was* * * § especially the 
case in Salix fragilis and cinerea and Pterocarya fraxinifolia. 
“ Sanio’s Bands” in the Coniferae.* — By this term ( Sanioische 
BalTceii) Herr C. Muller proposes to designate the beams or thickenings 
commonly found in the xylem-elements, chiefly in the tracheids of 
Coniferse. In the twenty-eight species examined, he found no ex- 
ception to their occurrence, but they are most frequent in Araucaria 
brasiliana and Salisburia adiantifolia. They occur in all the axial 
organs, in the stem, root, and branches, in both the older and younger 
parts, and not only in the xylem, but also in the phloem and cambium ; 
they are most abundant in the tracheids and in the sieve-tubes. They 
extend radially through the elements in which they occur, either singly, 
or more often in a large number of successive elements in the same 
radial row. Wherever a series of bands occurs in the xylem, a corre- 
sponding series is to be found in the phloem. They are probably 
formed by an infolding of the radial walls of the cambium cells. They 
exhibit the same microchemical reactions as the walls themselves ; in 
the xylem they are also lignified. Their physiological significance is 
at present uncertain. 
Suberin and Bark-cells.f — M. Gibson has found, in the cork of 
Quercus suber , besides Kiigler’s phellonic acid, two other acids, which 
he calls suberinic acid and phlo'ionic acid. The mode of separation of 
the three acids is described in detail. For phellonic acid Gibson gives 
the formula C 22 H 43 03 ; it is insoluble in water, soluble in alcohol, ether, 
and boiling chloroform. Suberinic acid has the composition C 17 H 30 O 3 ; 
it is insoluble in water, readily soluble in alcohol, ether and chloroform, 
insoluble in petroleum-ether. Phloionic acid, C 11 H 21 0 4 , is insoluble in 
cold, slightly soluble in hot water, soluble in alcohol, very slightly 
soluble in ether and chloroform. 
The author finds the so-called suberin-lamella of cork membranes 
to contain either no cellulose, or only a very small quantity. He believes 
it to consist of a mixture of compound ethers or products of the con- 
densation or polymerization of the various acids. 
Reactions of Lignin.J — According to Herr T. Seliwanow, the 
characteristic reactions of lignin are due to the lignified membrane 
itself, and not to the vanillin. In lime-wood the presence of vanillin is 
very doubtful. Pine-wood he regards, from its chemical reactions, as 
a compound of cellulose and a gum having the nature of an ether. 
Hypertrophy of Lenticeh.§ — M. H. Devaux states that the tuber of 
the potato normally possesses numerous lenticels; these lenticels are 
open and admit of free access of air to the internal tissues. If, however, 
* Ber. Deutsch. Bot. Gesell., viii. (1891) pp. 17-46 (1 pi.). 
t La Cellule, vi. (1890) pp. 63-14. See Bot. Centralbl., xlv. (1SS1) p. 111. 
X Arb. S. Petersburg. Natur.-Ver. (Bot.), xx. (1889) (Russian). See Bot. 
Centralbl., xlv. (1891) p. 279. 
§ Bull. Soc. Bot. France, xxxviii. (1891) pp. 48-50. 
