Magnolia yarumalense

The fruits are elliptical and asymmetric, measured from 4.2 to 6.7 cm long and from 3.2 to 3.6 cm wide; the central axis of the fruit has a length of 4.5 to 5.3 cm and from 1.4 to 1.7 cm wide; they open irregularly by detachment of the carpels. Each carpel has 1 to 2 seeds, and in total may contain about 27 seeds, many of them are not fully developed. The seeds have a fleshy scarlet red aromatic cover; the seed coat is hard, smooth, dark brown to black; their shape is triangular, measuring from 8.5 to 10.1 mm wide and from 8.3 to 9.1 mm high and from 3.9 to 4.6 mm thick. The moisture content of fresh seeds can be about 25.4%. The weight of 1'000 seeds ranges between 144 and 166 grams and one kilogram can contain between 6'000 and 7'000 seeds.^[4]

Fruits should be harvested during the months of August, September and October (high rainfall) that is the time which higher concentration of fruits. The fruits and the seeds can be collected directly from the ground, however, the falling green fruits usually contain few seeds developed; it is common to find fruits and seeds that are decomposed or attacked by insects. To avoid losses, plastic tarp can be placed under the canopy to collect material falling from the tree.

Another possibility is to climb the tree and collect seeds directly from open fruits or collect ripe fruits that are still closed and put in the post-mature processing and thereby control the process of dehiscence. If the tree is difficult to climb or the equipment is not adequate, the material can be collected using an extension pruning pole. The collecting features some of the following disadvantages: the fruits and seeds are susceptible to insect attacks, or are eaten by wildlife since they are an important source of food; many fruits that are still green with immature seeds are aborted; ripe fruits can dehiscence and drop the seeds. Because of this, the scarcity of individuals of this species, low seed production, the harvest time is still unknown, it has been necessary to develop an appropriate system in order to optimize the collection. The system consist in build a basket using wire and plastic mesh (with mesh size of 1 mm or less). This way it is possible to overcome the disadvantages mentioned and collect (manually or using an extension pruning pole) the green fruits that are closed to post-mature, open ripe fruits with the seeds still attached to the central axis or detached seeds. In all collection systems described above, the selection of seeds should be done. Seeds that present biotic or abiotic damage or any kind of infestation should be discard.^[4]

In accordance with previous studies it is not advisable to keep the seeds, because they are very sensitive to desiccation and they lose their viability. Nevertheless, if it is not possible to proceed to the sowing immediately we can keep it in the fridge for few days with the red sarcotesta in a closed container with wet substratum (sawdust or sans, among others) at low temperatures (4 °C approx.).^[4]

These seeds do not require a pre-germination treatment. Before sowing, it is advisable to stir the sarcotesta of the seeds, clean it with running water and emerge it into a solution of 1% sodium hypochlorite during 15 minutes to avoid fungal infestations. When these seeds are sowed in a substratum with soil under obscurity conditions could have a germination capacity that oscillates between 80 and 90%. Germination starts between 39 and 46 days after sowing and is completed between 20 and 30 days after. Nevertheless, when seeds germinate in a black bag with sawdust substratum the germination capacity oscillates between 68 and 100%, stars 55 days after sowing and is completed 2 months after. The germination is epigeous and starts each one month and a half after sowing and is completed 30 days after approx. Seedlings present a high percentage of survival within the replanting.^[4]

It is advisable to proceed to the dissemination as follows: we put some seeds in a black bag and with wet sawdust, after we close the bag and we leave in a nursery. This method allows to minimize the space used, does not present continuous risk, it is easier to control the insects attacks and/or pathogen, the substratum used is cheap and easy to get, the vegetal material produced is of good quality, among others advantages. It is recommendable to monitoring periodically in order to extract the seedling germinated. If we do not do this, the seedlings could suffer morpho-physiological damages such as malformation of the root system and forming mould. Other aspect to take in consideration is the position of the seed in open bags. It is important to sow it in a flat shape because that assures that the radicle is going to contact the substratum rapidly. When we sow in obscurity, once germinated, it is advisable to replant rapidly to avoid physiological problems such as moulding. The seedlings of this species present a high percentage of survival after replanting. They are plants of rapid growth initially and after slow. It is recommendable to keep it under shade or semi-shade.^[4]

• Botanical Garden of Medellín, and its scientific Director Alvaro Cogollo, leading Magnolia conservation science in Antioquia department.
• South Pole Carbon, company leading a Magnolia conservation programme in Antioquia with the help of carbon finance.