748 JOUKNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Since Professor Jones had proved that Pear blight may produce twig 

 blight in various kinds of Plum trees, it seemed probable that this blight 

 and rot of the Apricot was due to the same organism. 



Experiments were undertaken, which were repeated a number of times, 

 of inoculations of Apple twigs and fruits, and Apricot tw T igs and fruits, and 

 the results were the same, namely, a typical case of Pear blight from all 

 these sources. 



The residue of the bulletin is occupied with details of the inoculations, 

 and their results. — M. G. C. 



Aquilegrias, Hybrid (Garden, No. 170G, p. 69, 30/7/1904).— 

 Aquilegia vulgaris will generally take care of itself in the garden, but, 

 unfortunately, it is not so with most of the hybrids. All will grow in 

 shady places like true alpines, but as a rule they must have a light soil 

 if they are to last more than two seasons. They rarely make fine plants 

 in wet, heavy soils, and a damp season seems more fatal to them than 

 a severe one. Given a light soil, especially if it is a sandy one and not 

 too dry, many of them will last for years. If the soil is heavy the best 

 thing to do is to give a liberal supply of leaf -mould with it to a depth of 

 at least a foot, so that the soil does not become too close. 



The old-fashioned Aquilegias are essentially spring flowers, but the 

 hybrids are in bloom most of June and July, unless the season is a very 

 hot and dry one. Whatever the soil, it is a good plan to raise a fresh 

 stock of plants every two or three years, so that there may be always 

 a supply in their prime, which is in their second and third years. 



E. T. C. 



Aracese and Liliacese, The Development of the Central 

 Cylinder of.— By M. A. Chrysler (Bot. Gaz. xxxviii. No. 3, p. 161).— 

 After comparing Van Tieghem's and Jeffrey's system of development of the 

 variations from the protostele, the author examines numerous rhizomes 

 of these families. The conclusion is that monocotyledons were derived 

 from dicotyledons by the primary cylindrical stele breaking up into 

 strands. Thus, in Acorus Calamus the central cylinder of a seedling 

 consists in its lower region of a solid mass of vascular tissue composed of 

 a core of xylem and a ring of phloem, with pericycle and endoderm — 

 i.e. a typical protostele. A parenchymatous pith appears w 7 here the traces 

 of the second leaf are given off ; subsequently some bundles run inwards 

 into the medulla before turning out to the leaves. 



" The simple siphonostelic stage persists in Acorus for several inter- 

 nodes, and the stem looks much like that of a dicotyledon ; higher up 

 some segments of the stele become amphivasal, and this may be regarded 

 ;is the first appearance of a monocotyledonous character." 



" The plan of the young stele — e.g. Smilacina — bears a close resem- 

 blance to that of a dicotyledon, and differs from the older stele of a 

 dicotyledon only in the absence of cambium." 



From the above facts &c. the author concludes that "these con- 

 siderations lead to the conclusion that the monocotyledons are not an 

 ancient group, but that they have branched off from the dicotyledons " — 

 or, as an alternative, that both groups sprang from a common stock more 

 closely resembling that of dicotyledons. — G. H. 



