Anatomie. 339 



two methods it has been possible to prove that plenty of lime 

 precipitating acids (as malate, succinate, or Oxalate of lime (mag- 

 nesiaj? and alkali salts to a lesser extent as free acids) and sugar 

 is found in the hypodermas. Of special interest is the examination 

 of Peperomia magnoliifolia, whose thick hypoderma was separated 

 from the green tissue and thus gave very good evidence for the 

 presence of the said matters in the hypoderma itself. 



The plants examined were: Rosmarinus officinalis, Begonia, 

 Ficus elastica, F. pandurata, Peperomia incana, P. magnoliifolia, 

 Nerium Oleander, Cactus (stems), Smilax officinalis (roots). The sugar 

 found was partly cane-sugar partly glycose. Yet in Nerium (and 

 Smilax?) starch was found in the hypoderma as well as in the epi- 

 dermis, even when the pallisades were starch-free. 



Thus it is proved that hypodermas may contain products of 

 the chlorosynthesis-sugar or starch — or of the oxydation-organic 

 acids — , and from this it is concluded that hypodermas cannot be 

 regarded exclusively as organs for water-storage, as they have 

 generally been. Ove Paulsen. 



Groom, P., The Evolution of the Annual Ring and Me- 

 dullary Rays of Quercus. (Ann. Bot. XXV. p. 983 — 1003. 3 pl. 1911.) 

 The annual rings in Quercus may be recognised by the presence 

 of one or more of the following characters: 



1. Minimum calibre of the vessels in the outer zone and maxi- 

 mum of those in the inner. 



2. One or more layers of flattened fibro-tracheids with abundant 

 tangential bordered pits, forming the outer boundary of the ring. 



3. The cells of the medullary rays at the outer boundary of 

 the ring are shorter in length, have the terminal walls thickened 

 and have richly coloured contents. 



4. The ring usually dips inwards as it is continued across the 

 broad medullary ray. 



5. The tangential bands of parenchyma thin out and become 

 more densely coloured towards the outer part of the ring. 



The annual rings are most distinctly marked in the deciduous 

 species; the sub-evergreen forms shew a regulär and distinct pore- 

 zone but the difference in size of the vessels of the inner and outer 

 regions of the zone is much less than in the deciduous oaks, the 

 truly evergreen trees have no pore-zone. No species are destitute 

 of annual rings though in some evergreen oaks the boundaries of 

 the rings are difficult to follow. All species of Quercus have unise- 

 riate shallow medullary rays, but some have high multiseriate ones 

 as well. In some species these are transitional stages between mul- 

 tiseriate and uniseriate rays which may represent either integration 

 of numbers of narrow rays to build up a broad one, or disintegra- 

 tion of the broad ray into a number of narrow ones. The present 

 evidence is insufficient to decide which process is going on. Bailey 

 and Eames consider the narrow-rayed type is primitive, their view 

 is based on geological, ontogenetic and pathological evidence. Jost's 

 work on Fagus points in the opposite direction and considers the 

 broad ray as primitive. Jabor's observations on seedlings of Fagus 

 indicate that possible integration of narrow rays and disintegration 

 of broad rays may go on simultaneously in the rays of the same 

 annual ring. 



It is possible that these processes are not determined by phy- 

 logenetic characters but by physiological needs. E. de Fraine. 



