If a spare frame is not available, it is possible to use temporary structures made from loose bricks, breeze blocks, and so on, or even to utilise an open part in the garden without protection, say along the outside edge of the dahlia plot, but in such cases it is probably advisable to bury the pots completely, and also to give each plant a light cane.

The National Show, held each year in the two Royal Horticultural Society Halls, is one of the finest in the world at which the amateur predominates in the competitive classes. The trade exhibits also bear favourable comparison with those of other countries.

The usual potting mixtures are quite suitable, preferably containing some nourishment; John Innes No. 2 is particularly good.

Among its activities it makes available all known information on the dahlia, gives advice to members and affiliated societies, maintains a national register of judges and lecturers and co-operates with similar societies in other countries. Covering, as it does, an extremely wide area, there is a Northern Committee, which looks after the main interests of members north of the Trent, organising at least one provincial show, and staffing bureaux at the bigger Northern shows.

Camphor oil is obtained by distilling the wood or leaves of Cinnamomum camphora (L.) Presl, which is a native of China, Japan and Taiwan, the last island producing the greatest amount. C. camphora can be distinguished from the other species of Cinnamomum mentioned above by the leaves being pinninerved, whereas the others have three to five distinct nerves from the base of the leaves proceeding towards the tip; camphor also has stout dormant buds. A large proportion of the world’s camphor is now produced synthetically from pinenc, a turpentine derivative, or from coal tar. Camphor is used in the manufacture of celluloid, in disinfectants and chemical preparations, and has a wide range of medicinal uses. Safrole, produced from the residual oil after camphor extraction, is used in soap and perfume manufacture.

Other species of Cinnamotnum, whose barks are used as spices or in medicine include: C. culilawan (Roxb.) Presl from the Moluccas; C. iners Reinw., which occurs from western India and Tenasserim (Burma) to Malaysia, Indonesia and the Philippines; C. javanicum Bl. in Malaysia and Indonesia; C. part henoxylon (Jack) Nees in Tenasserim and western Malesia; and C. sintoc Bl. in Java. All the binomials and authorities in this section are taken from Kostermans.

Long stemmed blooms of Dahlia can be supported with pad of soft material used to support weak necked blooms-not required for stronger stemmed varieties. Stem and cane should be tied at not less than two places above and two below the first pair of leaves, ignoring the single leaves which occasionally appear.

If a light, thin cane is secured to the stem, extending from just below the bloom to a point about 1 foot below the first pair of leaves, the danger of breakage is negligible. Make one tie just below the bloom, and at least one below the first joint.

This tip is particularly useful with varieties with rather soft footstalks as these often bend beneath the weight of the developing bloom, although the stem usually stiffens once the bloom reaches maturity. In this case it is best to cut with the cane still tied to the stern, and to leave the cane in position until the bloom has been vased up and has had opportunity to become fully charged with water.

The nutmeg tree, Myristica fragrans, is unique among the spice plants as it produces two separate and distinct products – the nutmeg which is the kernel of the seed and the mace which is the dried aril that surrounds the single seed within the fruit. It is a spreading evergreen tree, usually dioecious, which is native to the Moluccas in the East Indian Archipelago, belonging to the small primitive family Myristicaceae. Nutmegs reached Europe after cloves.

By 1650 the order had become fairly effective. Most writers comment that the scheme was thwarted by fruit pigeons which swallowed the seeds and voided them on neighbouring islands. The original source of this statement, which has been faithfully copied, is hard to identify, but the story, like the seeds, is rather hard to swallow. It is possible that the spice occurred in regions of the islands unknown to the Dutch, and there was a brisk trade in spices by the natives with Mindanao and Kedah.

Although perhaps not entirely a matter proper to a treatise on dahlias, the period of a dahlia’s life in which it inhabits a greenhouse or frame plays such an, important part that it seems advisable to digress a little.

It may sound strange that so much stress is placed on keeping temperatures down, but whereas it is not difficult to maintain a reasonable temperature even on a cold clay by a variety of means, it is most difficult to prevent the temperature soaring on a sunny clay in a small house. Cuttings soon flag if exposed to excessive dry heat, and, once having flagged, are not only slow in recovering, but arc also more likely to damp off and much more likely to take a long while to strike. So the maxim is-shade!

Usually a water circulating heating system will give too much heat for a small house, while most alternative systems are either expensive or somewhat unsatisfactory in one way or another.

In the course of transporting, bleaching and grading the quills, some breakage takes place; the broken lengths and fragments of quills of all grades are bulked, packed in bales of 100 lb (45 kg) and are sold as quillings.

Feat herings grade consists of the inner bark of twigs and twisted shoots which will not give straight quills of normal length. They are thus also genuine cinnamon but they often contain a proportion of chips. Like the quillings, featherings are exported in bales of 100 lb (45 kg).

These oleoresins differ in the quality of their flavour and odour and in the content and composition of volatile oil and, therefore, in their flavour strength. Volatile-oil contents of commercial ‘cinnamon oleoresin’ have been reported to range from 16 to 60 per cent. The details of their preparation are more than usually meagre but Ceylon cinnamon yields 10 to 12 per cent of oleoresin with ethanol and 2.5 to 4.3 per cent with benzene, and according to Salzer Chinese cassia (from C.cassia) yields an oleoresin containing about 66 per cent volatile oil.

In Sri Lanka, cinnamon leaf oil is generally produced by steam distillation of dried leaves on rather simple, but nevertheless effective, equipment. At one time, two types of leaf oil were produced which possessed differing properties.

In the Seychelles, cinnamon leaf oil is produced by water – steam distillation (with cohobation) of leaves which are hand-stripped from shoots cut for bark production. Collection of leaves takes place at intervals of 18 to 20 months during January to September. The young leaves are unsuitable for distillation during the ‘flushing period’ which occurs in the rainy season from October to December. The average yield of leaves is 1.8 tonnes per hectare.

Leaves alone give a lower yield than a mixture of leaves plus twigs, and the best quality oil is obtained from material harvested in the summer and autumn from trees which are 5 to 7 years old.

Plants from a heated frame or greenhouse will have to be hardened off before being planted out, and it is usual to do this in cold frames, although an unheated greenhouse will serve.

pot tubers are miniature tubers grown under semi-starved conditions, usually in small pots, mainly to serve as an insurance policy against loss during the winter as they generally keep much better than the large open ground tubers. This is particularly helpful when using varieties which are difficult to keep. They have a very considerable commercial value as they can be sent out during the winter, and will safely travel long distances without risk of deterioration.

Water from the main is much freer from infection, and, if stood in the greenhouse for a few hours, or a little warm water is added to take the chill off, will be much safer to use even in the very early stages. Even then it is advisable when spraying to add a little permanganate of potash to the water, which for this purpose, particularly when spraying cuttings, should be Cleanliness at all stages must be the watchword; disease arising from neglected areas can ruin weeks or months of hard work. Wash down and thoroughly disinfect the greenhouse and frames at least once a year; this will mean emptying the greenhouse for a time, but it is well worth it.

Indonesian cassia (Cinnamomum burmannii (C.G. & Th. Nees) Bl. C. burmannii is the main source of Indonesian cassia, in which there is a considerable export trade. The tree is found in Sumatra, through Java, and eastwards to Timor, from sea level to 2 000 m.

The main centre of cultivation is the west coast of Sumatra in the Padang area between 550 m and 1300 m, at which altitudes the tree grows best. It is also grown at lower altitudes in Sumatra. A form in which the young leaves are red grows at the higher altitudes mainly in the region of Mount Korintji and is known as Korintji cassia; it is of better quality. A form with green young leaves, growing at lower altitudes, produces Padang cassia, also known as Batavia cassia or cassia vera.

A large number of insects have been recorded on cinnamon, but they usually represent single records in the early years of the century and none appear to have caused serious widespread damage.

The quality of the dried spice is primarily assessed on its appearance, size and the content and aroma character of its volatile oil. Dried cloves should be free of mustiness and mould and the best prices are obtained for whole dried cloves of a good bold size with a bright, uniform reddish-brown colour.

The quality of the dried spice is influenced by a number of factors which include the care taken in the harvesting, drying, cleaning and sorting operations and the conditions used for storage.

Termites never attack mature healthy trees, but will damage roots and stems of trees in a moribund condition. The red tree ant, Oecophylla longinoda Latr., known in Zanzibar as maji-ya-moto (`hot water’), is a serious nuisance in a clove plantation. It makes large nests about 15 cm in diameter by manipulating its larvae to sew the leaves together. The very active, pugnacious workers move up and down the trunk and limbs on foraging expeditions.