NOTES AND ABSTRACTS. 



159 



Rust, Dissemination of White-Pine Blister. By G. F. Gravatt and G. B. 

 Posey {Jour. Agr. Res. xii. pp. 459-462 ; Feb. 191 8). — The authors attribute 

 the spread of the aecidio-spores of Cronartium ribicola, the pine-rust, to the 

 gipsy-moth larvae which are often blown great distances (up to twenty miles) 

 by the wind. To this they ascribe the appearance of the fungus upon currant 

 bushes far from the place where Finns Strobus or other pine liable to attack is 

 growing. [This curious distribution has been noticed in Britain, although the 

 means is still obscure.] — F. J. C. 



Sareoehilus solomonensis Rolfe. (Bot. Mag. t. 8737 ; November 1917.) — 

 Native of the Solomon Islands. A plant which grows well under conditions of 

 great heat and moisture, in habit resembling a Phalaenopsis. Inflorescence a 

 long slightly pendulous raceme, flowers small, pale buff with small brown spots. 



L. C. E. 



Saxifraga manshuriensis Komarov. By M. L. Green {Bot. Mag. t. 8707 ; 

 April 1917). — A native of Manchuria and Corea. A hardy perennial for the 

 rock garden, flourishes well in moist shady spots. Flowers small, white, 

 numerous. — L. C. E. 



Seehiuin edule Sw. By O. Stapf {Bot. Mag. t. 8738; Dec. 1917). — Native 

 of tropical America. A monoecious climbing shrub ; will grow well in a con- 

 servatory but requires a lot of room. Fruit large and fleshy, deeply grooved, 

 sometimes beset with soft spinules. — L. C. E. 



Seed, Kome-Grown versus Imp 0 ted {Quart. Jour. For. Jan. 1918). — In the 

 building up of a home-grown tree seed industry, one of the principal facts to be 

 faced is that seed collected in the British Islands has not always been found 

 to be superior to, or even as good as, that produced abroad. In the main the 

 explanation of this may be sought in the known tendency, common to all living 

 organisms, to adapt themselves closely to the conditions of their native habitat, 

 and the power of transmitting the degree of adaptability acquired to the following 

 generations. Prima facie, therefore, it may be taken that in all cases native 

 seed is likely to prove the best. Trees grow comparatively slowly and are 

 correspondingly slow to re-adapt themselves to the conditions of a new environ- 

 ment. Thus species indigenous to a locality having an extreme continental 

 climate — i.e. a long, cold winter, very short spring, and short, but often exceed- 

 ingly hot, summer — or those trees which normally flourish at high altitudes, 

 have perforce to develop and ripen their seed quickly, and are apt to find, when 

 introduced, that the heat afforded by our insular summers is insufficient properly 

 to ripen their seed, despite the fact that the actual summer season is often longer. 

 The use of seed that is not fully ripe when harvested can only result in dis- 

 appointment, as will be seen hereafter. On the other hand, seedlings raised 

 in Britain from foreign- grown seed of such species are likely if they are at all 

 frost tender, to suffer badly from spring frosts, because our milder conditions 

 of climate induce earlier root activity, and result in the leaves being flushed 

 in spring before the danger of late frosts has passed. Caution is. therefore, 

 necessary both ways. 



Of the pines, larches, spruces, and firs, the cones of Weymouth pine release 

 ripe seed as early as September. Generally, however, the Coniferae do not 

 ripen their seeds till October and November, even, in the case of Scots pine, as 

 late as December, and in the majority of cases the cones only open under the 

 influence of the sun's warmth in the following spring. 



Testing and Germination. — To avoid waste of labour and nursery space, and 

 the consequent disappointment, all samples of seed should be tested before 

 sowing as to their percentage of fertility. Small parcels of seed, from 1 oz. to 

 4 oz. according to the size of the seeds, may be sent to any of the seed-testing 

 institutions, and assessed in accordance with the report received, or tests may be 

 carried out at home. Simple seed tests are based on the fact that the essentials 

 for rapid germination are an even temperature (from 6o° Fahr. to 70 0 Fahr.), 

 sufficient moisture, and free admission of the oxygen of the atmosphere, while 

 exclusion of light is also a contributing factor. If a given number of the seeds 

 to be tested be subjected to treatment fulfilling these conditions, the percentage 

 of fertile seeds can be readily ascertained. A rough and ready test is to cut 

 a few seeds in two, transversely, with a penknife. Their quality is then judged 

 from the appearance of the cotyledons. Another rough but good test for the 

 larger kinds is putting them in watpr and floating off the light and useless seeds. 

 Good seed should be plump, heavy, of good, bright colour, and have a sweet, 

 healthy smell, 



