JSOTES AND ABSTRACTS. 



159 



flower. Insects when caught become covered with pollen in their 

 struggles to escape, and in forcing their way out carry it to other 

 flowers. No other orchid is known to be sensitive. — F. A. W. 



Melon Culture. By F. Garcia (U.S.A. Exp. Stn. Neiu Mexico, 

 Bidl. 63 ; 10 figs ; 1907). — The outdoor culture of water-melons and 

 musk-melons in New Mexico is detailed. — F. J. C. 



Melon, Wild: Culture in Central Asia. By J. Balsacq 

 (Le Jardin, vol. xx. No. 466, p. 213 ; July 20, 1906). — An exhaustive 

 classification of twenty-nine varieties of melon, with notes on their 

 cultivation.— F. A. W. 



Morphological Notes, Protective Adaptations, I. By W, T. 



Thiselton-Dyer (Ami. Bot. xx. April 1906, pp. 123-127 ; 3 plates).— 

 No. xi. of this series concerns remarkable cases of mimicry. 



Mesembryantlicmum Bohesii is first described, a plant which is 

 practically composed of a pair of leaves. The leaves, known technically 

 as trigonously hemispherical, simulate in general appearance the angular 

 rock fragments amongst which the plant grows. Nor is the mimicry 

 confined to form, but the weathering of the stones is also imitated by the 

 pustular spots on the surface of the leaves. 



Another remarkable case of protective adaptation is found in 

 M. truncatum. Here the plant is reduced to a small succulent ball, 

 which, in colour and appearance, bears the closest resemblance to the 

 pebbles between which it is found. So much is this the case, that the 

 plant was picked up by its original discoverer in mistake for a stone. 

 The weathering on the stone is in this case reproduced by mottling on the 

 surface of the leaves. 



Concerning this species the author remarks : — ■" The Mesem- 

 bryanthemum had two problems to face : (1) How to minimise the 

 loss of water by transpiration : this is achieved by assuming the 

 spheroidal form with its minimum surface. But (2) as soon as it 

 became a succulent blob it was exposed to the danger of being eaten, 

 and it only escaped this by pretending to be an inedible pebble." 



A third case, Anacampscros papyracea, is also described. — A. D. C. 



Movement of Soil Moisture, Studies on the. By E. Buckingham 



{U.S.A. Dep. Ayr., Bur. Soils, But. 38; 23 figs.; February 1907).— A 

 technical paper tending towards the development of a theory regarding 

 the distribution of moisture in the soil analogous to the theory of elec- 

 trical and thermal potentials. The analogy is not perfect, however, since 

 the electrical and thermal resistance is practically independent of the 

 amount of current and heat passing, whereas the capillary potential and 

 resistance to flow are dependent upon the moisture contents of the soil. 



F. J. C . 



Musa, The Genus. By A. Pucci {Bull. B. Soc. Tosc. Ort. 8, 1906, 

 p. 235).- According to Dr. Sagot's work, " Les differentes especes dans 

 le genre Musa,'" it can be divided into three groups :— 



X, Giant Musas, e.g. M. Ensete. 



2. Those with fleshy, edible fruits, e.g. M. sapientum. 



