768 SUMMARY OF CURIiENT RESEARCHES RELATING TO 



was also obtained, beside Lypoxantbin and xantbin. That tbc substances 

 obtained result from tbc transformation of reserve products in tbc seeds, 

 is of course sbown by tbc fact tbat before germination there was no 

 asparagin nor any of tbe substances afterwards present. Tbc autbor 

 mcauwbilc abstains from general conclusions. 



(2) Nutrition and Growth (including Movements of Fluids). 



Assimilation and Expiration of Plants.* — Hcrr U. Kreuslcr de- 

 scribes exjierimeuts instituted to ascertain tbe influence of lower tem- 

 perature on tbe assimilation of jdants. 



Tbc plants observed were tbe bramble, bean, castor-oil, and cberry- 

 laurel ; tbe conditions of experiment and tbe metbods employed were tbe 

 same as on former occasions, but tbe temperatures were lower. At zero 

 tbe exbalation of carbonic anhydride was 17-20 per cent, of tbat wbich 

 occurs at 20° C. in tbe case of tlie cberry-laurel and castor-oil plant ; in 

 tbe case of the bramble, tbe exbalation was only one-balf of tbat at 10°. 

 Assimilation at zero is for tbe cberry-laurel only 8 per cent, of tbe 

 possible maximum. 



Production of Vegetative from Fertile Shoots of Opuntia.t — 

 Herr F, Hildebrand describes in detail experiments in causing fruits of 

 Opuntin to vegetate by detacbing tbcm and placing tbem in contact with 

 tbe soil. Tbe species experimented on were 0. Ficus-hulica, 0. Maffines- 

 quiana, and an unnamed cultivated species. In all cases tbe tendency 

 was for cultivation of tbis kind to produce vegetative ratber than fertile 

 sboots. In some cases fertile sboots were first produced, but tbe 

 tendency to tbe production of vegetative sboots gradually gained the 

 upjier band. The tendency to produce both fertile and vegetative sboots 

 can, however, be incited in almost any part of the plant by external 

 influences. 



Viviparous Plants and Apogamy.J — Herr E. H. Hunger describes 

 the appearance of viviparous buds in Poa bullosa and alpina, Poh/gonum 

 viviparum, Atherurus ternatus, Ficaria, and Fourcroya. In Poa bullosa 

 he thinks we have a true instance of apogamy combined with viviparous- 

 ness, and to a less extent in P. aljjinn, Polygonum viviparum, and 

 Fourcroya, but not in Atherurus ternatus or Ficaria ranunculoides. In 

 Poa lulbosa the bulbs are formed in the fructification, but not in con- 

 nection with the flowers, which are usually altogether wanting, or, if 

 present, unfruitful ; they consist of two or three leaves strongly 

 thickened at the base. Where seeds are produced, the resulting seed- 

 lings show no special hereditary tendency to tbe formation of bulbs. The 

 bulbs borne in tbe inflorescence also usually produced, on germination, 

 normal plants with no well-marked tendency in this direction ; while, on 

 the other hand, the terrestrial buds displayed the inherited tendency 

 very strongly. 



Conduction of Sap through the Secondary ■Wood.§— Herr A. Wieler 

 has investigated, in the case of a number of different dicotyledonous trees, 



* Bied. Ceutr., 1888, pp. 265-7. See Journ. Chcm. Soc. Lond., Abbtracts, 1888, 

 p. 742. t Ber. Deutsch. Bot. Gesell., vi. (1888) pp. 109-12 (1 pi.). 



X ' Ueb. ehiige vivipare Pflanzea u. d. Ersclieinung d. Apogamie b. derselben,' 

 G3 j)p., Bautzeu, 1887. See Bot. Ztg., xlvi. (1888) p. 3H2. 



§ rringahcim's Jahrb. f. Wiss. Bot., xix. (1888) pp. 82-137 (1 pi.). 



