ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 293 



stem-bundles which enter the hypocotyl are time only half as many as 

 those which form the primary root. 



Resin-Ducts and Strengthening-Cells of Abies and Picea.* — Her- 

 man B. Dorner has examined the minute structure of the leaf in a 

 number of species of these two genera of Coniferae dependent on the 

 number and position for absence) of the resin-ducts, and of the 

 strengthening cells or thick-walled cells usually found in connection 

 with the epiderm or with tlie ducts. 



Injury to Vegetable Cells caused by Cold, Plasmolysis, and 

 Desiccation.t — L. Matrnchot and M. Molliard have determined, as the 

 result of experiment, that the fatal injury to vegetable cells caused by 

 cold, plasmolysis, and slow or rapid drying in the open air (fanaison), 

 is in all cases due to the same cause, viz. an exosmose from the proto- 

 plasm, and especially from the nucleus, reducing the amount of water 

 in the protoplasm below the minimum required for carrying on vital 

 processes. 



Structure of the Malaxideae.f — Among other points, Prof. K. Goebel 

 notes the following as characterising the genera of this small family of 

 Orchideae (Malaxis, Microstylis, Sturmia). There is no true velamen, 

 as has been stated by other observers ; all the cells of the leaf-bases 

 (with the exception of the vascular bundles) form a water-absorbing 

 tissue, corresponding to the velamen of other Orchideae. Cells adapted 

 for the storing up of water are also found in the central cylinder of the 

 stem. Rhizoids occur on the outer leaves and on the stem. Certain 

 zones of the stem are regularly occupied by fungus hyphae, which occur 

 also more sparingly in the leaves and root. 



Stem-structure of Actinostemma biglandulosa.§ — W. Wallace gives 

 the following as the main points of interest in the anatomy of the stem 

 of this plant, a tendril-bearing liane with an annual stem belonging to 

 the Cucurbitaceae. The vascular bundles are primarily collateral and 

 remain so for a comparatively long period ; it is not until secondary 

 thickening has made considerable progress within the bundles that these 

 begin to acquire medullary phloem. At the base of the older stem are 

 a number of accessory bundles ; these have a longitudinal course in 

 the cortex, and proceed from a meristem which has its origin in the 

 endoderm. 



(.4) Structure rof Orgrans. 



Influence of Darkness on the Development of Flowers.|| — From a 

 series of observations on many different flowers, L. Beulaygue states 

 that, as a rule, flowers open later in the dark than in full daylight. 

 The colour is most commonly reduced in intensity, varying between a 

 very slight reduction to complete decolorisation. The flowers are mostly 

 smaller, while, on the other hand, their pedicels are sometimes more 

 developed. The weight and size of the flower, including the pedicel, 

 are smaller in flowers developed in the dark, with very rare exceptions. 



* Proc. Indiana Acad. Sci., 1899 (1900) pp. 116-29 (11 figs.), 

 t Comptes Rendus, cxxxii. (1901) pp. 495-8. 

 \ Flora, lxxxviii. (1901) pp. 94-104 (7 figs.). 

 § Ann. of Bot., xiv. (1900) pp. 639-45 (1 pi.). 

 U Comptes Rendus, cxxxii. (1901) pp. 720-2. 



June 19th, 1901 x 



