ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 323 



formation, where the first divisions in the initial layer are pcricliual in 

 spite of the considerable radial pressure which is exercised in the 

 phellogen cells as a result of increase in thickness in the interior of the 

 stem. The same applies to the periclinal divisions in the cambium of 

 the higher plants. Another instance of the influence of heredity is found 

 in the medullary rays iu the wood of Salix and JEsculus, which generally 

 remain only a single layer in width in spite of the numerous anticlinal 

 divisions occurring in the cambium cells as a result of radial pressure. 



Suckers of the Green Rhinanthaceae.* — A. Sperlich has studied 

 the development, structure, and cell-contents of the haustoria in Melam- 

 pyrum, Alectoroloplius, Pedicularis, Tozzia, and other genera of this 

 semi-dependent group of Scrophularinese. He finds that Melampyrum 

 pratense, silvaticum, and nemorosum live not only saprophytically but also 

 parasitically, the two methods being combined in the nourishment of the 

 same individual. The haustoria attach themselves to living as well as to 

 dead nutritive objects, and differ in this respect from M. arvense and the 

 other Rhinanthaceaa. The hyaline tissue which forms the central mass 

 of the sucker originates through growth in the pericambium and endo- 

 dermis on the side towards the nutritive object ; it is limited, except at 

 the place where the haustorial process will be formed, by a row of cells, 

 the membrane of which gives, to a large extent, the reaction of an endo- 

 dermal membrane. Tracheides are not formed in all the suckers ; their 

 appearances seem governed by exigencies of conduction. The suckers of 

 Melampyrum produce, when attached to suitable objects, a wedge-like 

 process, the terminal-cells of which elongate often in a hyphal manner 

 and penetrate fungus-like the nutritive object. 



Proteid crystalloids were found in the nuclei of the cortical paren- 

 chyma and hyaline tissue in Melampyrum. The resemblance previously 

 pointed out by Koch of certain structures found in the cell-plasm of the 

 hyaline tissue, to the bacteroids of Leguminous tubercles, was confirmed 

 by the similar behaviour to a series of reagents in both cases. The 

 hyaline tissue is rich in proteid ; starch is also common, and in young 

 stages amylodextrin. The presence of glycogen (or a nearly allied body), 

 rhinanthin, phosphoric acid, and nitrates was also demonstrated. Similar 

 contents were found in the other genera investigated. 



The author concludes that this tissue of hyaline cells is a centre for 

 the anabolic processes involved in the supply of material for the growth 

 of the plant. After ripening of the fruit this function ceases, and it 

 serves henceforth as a place for deposition of reserve-materials. 



Assimilation of Carbon by a Green Alga.f — P. G. Charpentier Is 



cultivated Cystococcus humicola in a nutrient solution containing sul- 

 phate of magnesium, bi-potassic phosphate, nitrates of potassium and 

 calcium, with traces of ferrous sulphate, and 10 grin, glucose to 1000 

 grm. water. The plant grew well, quite independently of the car- 

 bonic acid of the air, at the expense of the sugar contained in the 

 solution. Like other lower Algae it retained its green colour, due to> 

 chlorophyll, in darkness, but light was proved to be very beneficial to 

 the plant ; a culture made in the light yielding 330 mgrm., while one 



* Beiheft. Bot. Oentralbl., xi. (1902) pp. 437-S5 (1 pi.). 

 t Compt. Rend., exxxiv. (1902) pp. 671-3. 



