ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 539 



The author describes six ways of arrangement of the fibro-vascular 

 bundles in the midribs of the leaves : the number of bundles varies 

 between one and seven. He also describes the characters of the 

 cotyledons ; the spongy parenchyma of these organs in Actinostemma 

 racemosum has a reticulate appearance, the cells radiating from a 

 fibro-vascular bundle and bearing very large intercellular spaces, 

 recalling the leaf tissue of water-plants. The young roots of the 

 same species have also remarkably wide inter- cellular spaces. The 

 epidermal cells of the fruit may be radially flattened, cubical or 

 radially elongated ; a more or less complete sclerenchymatous ring is 

 generally formed in the pericarp. The origin of the tubercles on the 

 surface of the fruit varies : those in Actinostemma and Momordica are 

 parenchymatous out-growths, while those of Cuaimis sativus are the large 

 protuberant bases of trichomes which have become detached. Sieve- 

 tubes have a characteristic distribution in the fruits : besides those found 

 in the phloem, there are isolated ones in the tissue of the pericarp, in the 

 hypoderma outside the hardened ring, when such is present. A 

 vascular bundle enters the tubercles on the pericarp in Momordica Cha- 

 rantia. Three kinds of epidermal cells may be distinguished in the 

 seeds, flattened or cubical, prismatic, and prismatic with thickened 

 ridges. 



Development of the Bicollateral Bundle of Curcurbita.* — F. C. 

 von Faber has worked out the development in Cucurbita Pepo, and finds 

 that the bundle is a true bicollateral one. The inner phloem is differ- 

 entiated at a very early stage in the same procambium strand as the 

 other elements, and differs in no way from the external phloem ; hence it 

 seems more correct to speak of a single bicollateral bundle than to regard 

 the inner phloem as belonging to a second bundle which consists only of 

 phloem. The development of an internal cambium, and the occasional 

 formation of xylem elements in connection with the inner phloem, cannot 

 be regarded as an argument against the original entity of the bundle. 



Leaf-form and Stomata of the Dwarf Plants of the Wiirzburg 

 Limestone. f — E. Lippold has made a detailed comparison of a number 

 of plants growing in the area in question, in which there is a marked 

 scarcity of water, with others growing under normal conditions, from 

 the point of view of leaf -area and distribution of stomata. A reduction 

 of leaf -surface is general in the dwarf forms ; an extreme case is seen in 

 Pimpinella Saxifraga, where it is in the proportion of 24 to 1. There 

 was also a reduced number of stomata on a square millimetre of surface; 

 here the extreme case was supplied by Poterinm Sanguisorba, the re- 

 duction being in the proportion of 1*8 to 1. The form and often also 

 the size of the epidermal cells was unaltered in the dwarf forms. 

 Generally speaking, the leaves were hairy on both sides. Transpiration 

 is checked in these dwarf forms by one or a combination of more than 

 one of the following factors : reduction of the leaf -surface, diminution 

 of the number of stomata in unit area, diminution of the size of the 

 stomata. 



* Ber. Dentsch. Bot. Gesell., xxii. (1904) pp. 296-303 (2 pis.). 



t Verhandl. Pbysik.-Medicin. Gea. Wurzburg, N.F., xxxvi. (1904) pp. 337-83 



2 P 2 



