Description
of seeds belonging to the Angiospermae
(Calycanthaceae) Sow in the autumn or in the spring with seeds vernalized for 4 weeks.
Carpinus betulus L. common hornbeam (Corylaceae) If the water content of the seeds does not fall below 9-11%, then the wingless seeds may be kept in air-tight containers at temperatures from -7 to +3°c. When possible, sow the seeds immediately after their harvest, when they are still green (at the end of the summer). For springtime sowing, use more mature seeds, (harvested in the autumn), which have been stratified in the warm for 2-8 weeks and then in the cold for 12-14 weeks, or have undergone 4 successive cycles of warm-cold stratification: 2 weeks of warm stratification followed by 2 weeks of cold stratification, carried out 4 times. When the first seeds begin to germinate, at the end of the period of cold stratification, it is time to sow the seeds. It is best to do this in late springtime, since the germination of treated seed is encouraged by temperatures of around 20°c. The seedlings should be shaded slightly from emergence until the end of the summer.  Seeds of Carpinus betulus
Castanea sativa Miller sweet chestnut, Spanish chestnut (Fagaceae) Sow in autumn, or in springtime with seeds which have been vernalized as soon as they were harvested. Dehydration has an extremely negative effect on the vitality of the seeds; the water content must be maintained at around 45-50%.
Catalpa bignonioides Walt. Indian bean tree (Bignoniaceae) Spring sowing with untreated seed or using seeds which have been cold stratified for a short period. The seedlings must not be sown too densely.
Celtis australis L. nettle tree (Ulmaceae) Sow in the autumn, or in the spring with seeds which have been vernalized for 8-12 weeks. Check the seeds often in their soil and interrupt the treatment as soon as germination begins. In some cases, the fruits are steeped to remove the pulp, in order to prevent mould from forming. Vegetative propagation possible.  Seeds of Celtis australis
Ceratonia siliqua L. St. John’s bread (Leguminosae) May be sown in autumn, immediately after the harvest, or in springtime with seeds which have been treated in one of the following ways: a) soaking in hot water (see Acacia
sp.);
Cercis siliquastrum L. Judas tree (Leguminosae) Sow in the spring, if possible with scarified seeds. See Acacia spp.
Chamaerops humilis L. St. Peter’s palm (Palmae) Soak the fruits in lukewarm water for 24 hours and bring them to germination in a warm bed, between +20 and +25°c. It is advisable to remove the pulp by steeping for 4-6 days, since the fleshy tissues give off an unpleasant smell and are also a vehicle for pathogenic agents and substances which inhibit germination. Vegetative propagation possible.
Chaenomeles japonica (Thunb.) Spach (Rosaceae) Sow in the late autumn, immediately after harvesting, or in the spring with seeds which have been estivated for 2 weeks and then vernalized for 8-16. Vegetative propagation widespread.
Citrus trifoliata L. (Rutaceae) Seed propagation is used to obtain plants to use as root stock. When partially dehydrated seeds are used, germination takes a long time, it is therefore a good idea to maintain a humidity level of around 56%. Sow in the spring with seed which has been cold stratified for 5-12 weeks.
Cornus mas L. cornelian cherry (Cornaceae) The seeds of this species have a complex and accentuated dormancy. Even today, we are not aware of any really efficient means of stimulating rapid germination, although there are on-going studies in this field. Autumn sowing, immediately after the harvest, otherwise, in late autumn with seeds which have been stratified in the warm for 12-16 weeks. In order to be sown in the spring, the seeds must first be aestivated for 16 weeks and then vernalized for 4-16. Vegetative propagation possible.  Seeds of Cornus mas
Cornus sanguinea L. common dogwood (Cornaceae) Sow in the autumn immediately after the harvest, or in the spring with seeds stratified in the warm for 8 weeks and in the cold for 8-12.
(Corylaceae) At dissemination, the seeds have a water content of approximately 40%, and are damaged by dehydration. The water level should never fall below 13-15%. This is a point to take into consideration when buying hazelnuts to sow, which are very different from those sold for consumption, with a humidity level of no more than 5%. Approximately 30% of seeds are not dormant at the time of harvesting, but fall dormant 2 or 3 weeks later, kept in a dry environment. Before sowing or stratification, it is a good idea to soak the seeds for 2-3 days; they may also be disinfected in a solution of sodium hypochlorite at 1%, for 5 minutes. Cold stratification can be substituted by a treatment with gibberellic acid at 100-200 ppm. for 18 hours, to be applied to the shelled nuts. If sowing takes place in the winter in a protected environment (greenhouse or similar) for particular reasons (innoculations with funghi), take into account that the minimum duration of stratification is one month, although a period of 50 days vernalization gives better results.
(Rosaceae) Seed dehydration compromises germinability, and it is therefore advisable to sow in the autumn, straight after the harvest. Spring sowing requires seeds which have been stratified outdoors all winter, or which have undergone thermal treatments in controlled environments : estivationfor 1.5-3 months and vernalization for a further 3. Vegetative propagation is very common.
(Rosaceae) Spring sowing with pretreated seeds. The seeds have an endogenous dormancy which can be interrupted by warm stratification for 4-16 weeks (generally 4-8), folowed by cold stratification for 12-36 weeks (generally 12-16). Some authors suggest scarification with sulphuric acid (from 30 minutes to 2 hours for C. monogyna) followed by 4 weeks of warm stratification and 12 of vernalization. In many cases, sowing is carried out in seed beds immediately after the harvest, then transplanting takes place in the spring. Vegetative propagation is possible.
(Leguminosae) Spring sowing. The seeds have a physical type of dormancy and therefore require treatments which break into the hard, external integuments. Vegetative propagation is widespread. See Acacia spp.
Cytisus spartium scoparium (L.) Link common broom (Leguminosae) Sow in spring. Further to the treatments indicated for Acacia spp. chemical scarification is also suggested, by soaking in sulphuric acid for 15-30 minutes. Vegetative propagation is common. See Cytisus spp.
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