Description
of seeds belonging to the Angiospermae
Maclura pomifera (Raf.) C.K. Schneider osage orange (Moraceae) The fruit pulp is removed by steeping the fruit in water, or via fermentation. Sow in the autumn or in the spring with seeds which have been cold stratified for 30 days. An alternative to vernalization is to soak the seeds in water for 2 days, although this is not as effective. It is common practise to form heaps of the fruit as they fall in the autumn, then to leave these outside for the whole of the winter . In early spring it is then easy to recuperate the seeds after soaking. These can then be sown immediately with excellent results.
(Magnoliaceae) The species used as root stock for others for whichfor which propagation by means of cuttings is problematic, are generally grown from seed. The seed has a high oil content and is very appealing to rodents. Deterioration is rapid, so local seeds are preferred. Autumn mulched sowing or spring sowing with seeds vernalized outside during the winter, or in controlled conditions for 45 days.
Magnolia grandiflora L. white magnolia (Magnoliaceae) See Magnolia spp.
Mahonia aquifolium (Pursh) Nutt. (Berberidaceae) The seeds are very susceptible to dehydration, and their dormancy depends on the immaturity of the embryo at the moment of dissemination, and varies dramatically depending on the geografical origin. Sow in the autumn or in the spring with seeds which have undergone cold stratification for 90-145 days. Some authors propose 4 months of aestivation followed by 4 months of cold stratification as an alternative to vernalization alone. Vegetative propagation very common.
Malus sylvestris Miller common crab apple (Rosaceae) These seeds cannot stand dehydration, which, if it reaches critical levels, may bring about secondary dormancy and a reduction in germinability. The moisture level should be kept at around 9-10% in order to store the seeds well. Sow immediately after the harvest, or in the spring with seeds stratified in the warm for 2-4 weeks and in the cold for 12-16 weeks. Seeds set aside for spring sowing should be dried first and then kept carefully in a cold place, at temperatures from -18°c to +3°c., until the beginning of stratification. In many cases, stratification is carried out outside from the moment of harvesting to sowing. Sowing in the late spring may induce secondary dormancy if the ground temperature goes above certain levels. This is often used as root stock.
(Meliaceae) In general, steeping is used to remove the pulp from the fruit and the endocarps (‘bones’ containing 4-5 seeds each) are then planted immediately after the harvest or in the spring.
(Moraceae) Sow in the autumn after soaking in cold water for 4 days, or in the spring with seeds which have been vernalized without a substrate for 30-90 days.
Myrtus communis L. common myrtle (Myrtaceae) Seed propagation is practicable, but the initial development is rather slow. The cold stratification of the seeds for 30-60 days allows more complete and simultaneous germination. Sow in the late autumn, immediately after harvest, or in the spring with vernalized seed.
(Nandinaceae) The flesh of the fruit is removed by soaking to obtain clean seeds, 2 per berry, which, at dissemination, contain immature embryos. Strangely enough, the physiological evolution of the embryos takes place at both high and low temperatures, regardless of the water level of the seeds, so that germination occurs at the same time (late autumn, early winter of the following year) both for seeds sown straight after the harvest, and for those carried out with matter kept at low temperatures (+5°c) for 9-10 months. Some authors suggest a long period of aestivation followed by a few months of vernalization, others advise cold stratification only for 3 months. Vegetative propagation is very common.
Olea europaea L. var. europaea olive (Oleaceae) Fruits whose flesh has been removed by soaking are used for sowing. Mechanical or chemical scarification may accelerate germination which is temporarily inhibited in the wild by inhibiting substances present in the endocarp (bone) and in the seed coverings. Sow in the autumn with no treatment, or with seeds which have been soaked in sulphuric acid for 24 hours, and then washed for 2 hours. In both cases, sprouting may occur during the second spring. The use of seeds which have been vernalized for 18 months is an alternative to the chemical treatment. Another technique consists in soaking the seed in water for 1 week, after the flesh has been removed. After this, the seeds are stratified under natural conditions for 50 days. The water should be changed every day, and the stratification material must be well drained and insulating. After these treatments, which usually begin in July, the seed is sown in large boxes in sheltered places (greenhouses). A growing method which was very widespread in the 60’s was to put the fleshless seeds in the earth in seed beds, built in brick, and protected by glass, at the end of the summer. The slow, staggered germination carried on until the end of the winter, when it was possible to begin transplanting, using seedlings with 2-5 pairs of leaves. Vegetative propagation very widespread.
Ostrya carpinifolia Scop. hop, hornbeam (Corylaceae) The seed will keep for 1-2 years if it is placed in air-tight containers at low temperatures (between -7 and -5°c) , and has a water content of 10-12%. Sow at the end of the winter, the beginning of the spring with seeds which have been stratified at warm temperatures for 4-8 weeks (for seeds which come from the south, 4 weeks should be sufficient), and then at low temperatures for 16-23 weeks. Before beginning the thermal treatment, we advise soaking the seeds in water to separate the empty seeds, which usually float. Germination of pretreated seed (not dormant)is encouraged by the daily alternance of cold night temperatures-warm day temperatures, so it is therefore not a good idea to carry out sowing in the late spring.  Seeds of Ostrya carpinifolia
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