Description
of seeds belonging to the Angiospermae
Tamarix gallica L. (Tamaricaceae) In natural conditions, the germinability of the seeds, which are very small, declines rapidly. Sow in the spring in seed beds, then transplant. Germination takes place quickly, but the initial development of the seedlings is slow. Vegetative propagation widespread.
Tilia americana L. American lime (Tiliaceae) The dried seeds can be stored for at least 4 years, in air-tight containers at temperatures from +1-+3°c. Inhibitory factors present at the embryonal level together with the impermeability of the pericarp result in a complicated state of dormancy. Soak the seeds in concentrated sulphuric acid (97%) for 15 minutes, wash well, and leave to soak in water for 12-24 hours. Following this treatment, the seeds are stratified in the cold for 14 weeks and sown in the spring.
Tilia cordata Miller small-leaved lime (Tiliaceae) The seeds keep well for 2-3 years if they are stored in air-tight containers at temperatures ranging from -10 to -5°c. The water content of the seeds must first be reduced to 8-10%, however. The dormancy of the seeds of this species is very marked and depends on physiological factors associated to the embryo and to the progressive impermeability of the seed integuments, which reaches its height at the end of ripening. If no pretreatment is carried out, the sprouting of these seedlings continues for 3 years. Up to now, however, no treatments have been found which are completely effective in interrupting dormancy. Harvesting should be carried out as soon as the fruits change colour, darkening from green to brown, and sowing should take place immediately (in this way, the water content of the capsule must not be less than 50-60%) . If the seeds to be used have been harvested in late autumn, from the end of September -October onwards, with a water content of no less than 15%, the following treatment may be used to violate the integuments : the seeds should be soaked in plenty of hot water (70°c) and left to cool, the seeds which sink should be gathered, whilst the treatment should be repeated 4 or 5 times for those seeds which float. Once the seeds which have sunk have all been collected, they should be stratified in the warm for 4-20 weeks and in the cold for 16-20, then sown in the spring. The seeds which continue to float after 5 or 6 periods of soaking may be considered empty. Alternatively the same method may be used as that described in Ostrya carpinifolia.
Tilia europaea L. (Tiliaceae) See T. cordata.
Tilia platyphyllos Scop. broad-leaved lime (Tiliaceae) See T. cordata.  Seeds of Tilia platyphyllos
Trachycarpus fortunei (Hookes) Wendl. (Palmae) The seeds of this species are susceptible to dehydration; after one month from the date of harvest, the germinability diminishesdecreases noticeably . Sow in a warm bed with temperatures from 20-30°c., immediately after harvesting. Like most palms, these seeds germinate slowly: in optimal conditions the rootlets appear after 30-40 days after sowing, but the emergence of the epigaeal part takes place much later. Removal of the fleshy mesocarp and scarification of the woody endocarp speed up germination.
(Ulmaceae) Sow immediately after the harvest (spring) if possible the same day. See U. pumila.  Seeds of Ulmus campestris
(Ulmaceae) The seeds can be stored for one or two years, as long as the water content is reduced immediately after harvesting, from approximately 40% to a level of 3-8%, and the seeds are kept in air-tight containers at a temperature between -18 and -4°c. If these indications are not closely followed, the germinability of the seeds declines rapidly, and so in this case, it is better to sow straight after the harvest (spring), after soaking the seeds for 24 hours. It is of the utmost importance that the topsoil be kept damp. with favourable climatic conditions, germination begins after a few days.
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