522 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



prick out into small pots and cover with a bell glass. It can also be propa- 

 gated from cuttings, or treated like a Dahlia and grown from the tubers which 

 are dried before winter. The stalk attains a height of two feet, and is weighed 

 down by the abundance of purple flowers with which it is covered. — 5. E. W. 



Mechanical Analyses conducted at Varying Temperatures, Note on the 

 Effect of Changes in the Viscosity of Water on. By G. W. Robinson {Jour. 

 Agr. Sci. vii. Part 2, pp. 142-3 ; Sept. 1915). — A mixture of fine sand and silt 

 was submitted to mechanical analysis, by sedimentation, at temperatures of 

 6°C, ii°C, and i6°C. The amounts of fine sand found at these temperatures 

 were in the proportions 100, 105-7, and io8 - i respectively. These discrepancies 

 are due to the decrease in the viscosity of water as the temperature rises, resulting 

 in a smaller deposition of larger particles at the lower temperature. It is therefore 

 recommended that sedimentation should be carried out as far as possible at a 

 uniform temperature, say I2°C. to I4°C. — /. E. W. E. H. 



Meconopsis Prattii (Bot. Mag. tab. 8619). — Western China. Family Papavera- 

 ceae. Herb, 1-3 ft. high. Leaves rosulate, 3-5^ in. long, hirsute. Flowers 

 in racemose cymes, 2 in. across. Petals 6-8, bright blue, flushed with purple. 

 Anthers pale yellow. — G. H. 



Melons, Fungus Attacks. By E. Molinas (Le Jard. vol. xxviii. pp. 215, 216, 



2 figs.). — Attacks of Plasmopara cubensis, which makes yellow blotches on the 

 upper surface of the Melon leaves, can be prevented by spraying with 1 per cent, 

 solution of copper sulphate. Dusting with flowers of sulphur, mixed with 

 £ of its weight of powdered quicklime, checks the ravages of Sphaerotheca Humuli 

 and Erysiphe Polygoni. No cure is known for Colletotrichum oligochaetum and 

 Scolecotrichum melaphthorum. These fungi cause brown marks on the leaves, 

 stems, and fruit, giving the last a nauseous bitter taste. Collect and burn the 

 diseased parts. 



Spraying with copper solutions checks leaf scorch, due to Alternaria Brassicae 

 and A . Cucurbitae. If the Melon shows signs of rotting at the neck, plaster the 

 affected part with Bordeaux mixture. Repeat the treatment from time to time. 

 Green fly and red spider are destroyed by spraying with a mixture of soap 

 and nicotine. Attacks of caterpillars and grubs are prevented by watering 

 between the plants with a 2 per cent, solution of potassium sulpho-carbonate. 



S. E. W. 



Mesembryanthemum stylosum {Bot. Mag. tab. 8595 B). — South Africa. Family 

 Ficoideae. Tribe Mesembryeae. Herb, small, succulent. Leaves fused below with 

 2-lobed apices 1-2 in. long. Corolla f-i| in. across, yellow. — G. H. 



Mesembryanthemum thecatum {Bot. Mag. tab. 8595 A). — South Africa. Family 



Ficoideae. Tribe Mesembryeae. Herb, small, stemless, succulent, tufted. Leaves 

 consolidated in obconic bodies £ in. thick, bluish-green. Corolla \-% in. across, 

 rose-purple with yellow eye. — G. H. 



Metrosideros diffusa {Bot. Mag. tab. 8628). — New Zealand. Family Myrtaceae. 

 Tribe Leptospermeae. Shrub, far-climbing. Leaves short-petioled ; blade oblong, 

 i-f in. long. Flowers cymose ; corolla, petals, orbicular, £ in. across, pink. 



G. H. 



Mistletoe. By M. A. Meunissier {Jour. Soc. Nat. Hort. Fr. June 1914, P- 432). 

 — The French Minister of Agriculture has caused an inquiry to be made into the 

 subject of the propagation and harmfulness of mistletoe. The results appear 

 to show that certain trees are quite immune from this parasite, and that it is 

 probably not seriously harmful except perhaps on certain trees, or unless it is 

 present in great quantity. Poplars, pears, and almonds are said to be those 

 which do suffer from its presence, and the apple and the poplar are of all 

 trees its favourite lodging-place. It is considered probable that there are 

 several sorts of mistletoe, and that the variety peculiar to one kind of tree will 

 not grow on any other. It prefers chalk or clay and chalk soil, and has been 

 noticed in the Alps at a height of 1,100 metres. Certain birds and even the 

 squirrel are said to disseminate the seed. — M. L. H. 



Momordes tigrinum {Bot. Mag. tab. 8597). — Upper Amazon. Family 

 Orchidaceae. Tribe Vandeae. Herb, epiphytic ; pseudo-bulbs 4-7 in. long. Leaves 

 ft. long. Scapes 4-6 in. long. Flowers, sepals spreading, lanceolate, yellow, 

 with purple blotches ; petals purple, with numerous darker purple blotches ; lip 

 small, incurved. — G. H m 



Mutation in Oenothera, Additional Evidence of. By H. H. Bartlett, 



with 17 figs. {Bot. Gaz. vol. lix. p. 81). — This long and elaborate paper brings out 

 certain facts which appear to be incompatible with earlier experiments leading 



