ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 53 



selves more of the visits of bees. In Luffa cylindrica the male flowers 

 are provided with a bract, which bears from two to six glauds on its 

 underside, forming an extra-nuptial nectary. The stamens also form, 

 as in Cucurbita, a nectar-receptacle at their base. The female flowers 

 have honey-glands on the outer side of the calyx, and five globular 

 structures in the place of stamens, between which and the style is an 

 annular honey-pit. 



Colour of Juniper-" Berries."* — M. Lendner does not confirm 

 Nestler's statement that the black colour of the so-called " berries " of 

 the juniper is due to a parasitic fungus, though fungus-hyphae are occa- 

 sionally found in them, but only exceptionally. It is rather due to 

 the accumulation of a substance allied to the tannoids in the epidermal 

 and hypodermal cells, which substance becomes subsequently trans- 

 formed into another of the same very dark colour. The active factor 

 in the change is probably the oxygen of the atmosphere. 



Anatomy of Pedicels.j — A. Pitard discusses in detail the anatomy 

 of the pedicel of flowers and fruits. The peculiarities of structure are 

 described which are correlated with the increasing weight of the fruit, 

 and with the need for the transport of food-materials. In the case of 

 flowers which have become double under cultivation, the sclerenchy- 

 matous tissue is strengthened and often becomes lignified at an earlier 

 period. In erect axillary flowers the medullary parenchyme of the 

 pedicel is strongly developed, with a few scattered centrifugal vessels ; 

 when the flower is lateral, the pith is less strongly developed and the 

 vessels are more numerous with a centripetal arrangement. 



Mechanism of the Awns of Stipa.J — L. Murbach describes the 

 mechanism of the seed-burying awns of Stipa avenacea. He confirms 

 the view taken by other observers that the cause of the twisting of the 

 awn is located in the individual cells ; not only a layer of cells, but 

 the whole of the mechanical cells, are active in bringing about this 

 result. The twisted portion of the awn is composed principally of 

 sclerenchymatous cells with a fibro-vascular bundle in the centre and 

 a band of chlorophyllous tissue on each side ; the mechanical cells are 

 distinguished by their remarkably small and eccentric cell-cavities. 



Colour of Box-leaves.§ — According to Prof. E. Chodat, the bright 

 orange-red colour frequently assumed by leaves of the box growing in 

 rocky or sandy places, is due to a modification of the chromatophores. 

 The white band which runs along the mid-rib on the under-side of the 

 leaf is caused by the fact that the hypodermal cells of this region con- 

 tain crystals of calcium oxalate, between which are retained bubbles of 

 air which are exceedingly difficult to displace. 



Chlorosis caused by the Nature of the Soil. || — J. A. CI. Eoux 

 has grown a number of silicicolous (arenaceous) plants in calcareous 

 soils, and finds that, although the seeds germinate readily, the seedling 



* Ann. Sci. Pkys. et Nat., ix. (1900) pp. 494-5. Cf. this Journal, 1900, p. 3G5. 

 t ' Kech. 8. l'anat. compare'e d. pe'dicelles floraux et fructiferes,' Bordeaux, 1899, 

 i pp. and 5 pis. See Bot. Centralbl., lxxxiv. (1900) p. 18. J 

 X Bot. Gazette, xxx. (1900) pp. 113-7 (5 figs.). 

 § Avch. Sci. Phys. et Nat., ix. (1900) pp. 488-9. 

 i| Ann. Soc. Linn. Lyon, xlvi. (1900) pp. 87-98. 



