Mimetes have the same ant helpers at seed drop, however some produce more and smaller seeds than the others. Mimetes hottentoticus, M. argenteus, M. arboreus, M. splendidus, M. saxatilis, M. chrysanthus and M. fimbrifolius produce 0 to 2 large seeds per floret while the M. capitulates (the first seeds on the sunward side are ripe earlier) and M. hirtus 0 to 5 seeds and Orothamnus zeyheri up to 18 seeds and these last 3 are more fragile and should be treated with care.
Members of Mimetes have individual florets, varying up to 30 on an inflorescence and yield a maximum of 2 seeds per floret, with an average of 10% producing seeds per inflorescence. The seeds visually resemble those of Leucospermum , have the same pollinators, ant dispersal and storage. Bagging them is the best way for seed collection and the heads can be pruned off when seeds are seen in the bag or when shoots start developing immediately below the lowest floret. Exceptions are M. capitulatus and M. hirtus that have much smaller seeds, in greater numbers and the seeds are more fragile.
With human attempts at germination, the first step is to clean off the elaiosome, the soft fleshy coat that the ants use. The seeds should be soaked in water overnight, spread onto rough concrete and rubbed using a wad of cloth. With some species the elaiosomes are tougher to remove so repeated rubbing and washing may be needed. After the elaiosome has been removed, dropping the seeds into water will allow the non-viable seeds to float and those can be discarded.
The next very thin coat which is the barrier to oxygen penetration is more of a problem. One method is to place the seeds in a strong cotton bag, add sharp sand and rub/wash and discard “blunt” sand, rub/wash again. A better method is to use a rubber car foot mat to trap the seeds in the little hollows and with a circular motion, rubbed over rough cement.

Figure 5. Photo showing the seed of a Leucospermum
In the photo above on the left the eliasome has been scratched, showing penetration down to the hard black nut. The very thin oxygen excluding coat is just showing, while (right) that coat has been mostly abraded off. A fresh seed has a thicker and softer eliasome to that in the image – it was a few days before I could get it under a microscope.
Tests have shown that there is a better germination if the thin coat is reduced ( about 20% better), probably due to the easier penetration of oxygen. Removing this inner thin coat can be partly avoided if the eliasome is cleaned off immediately after harvesting and the seeds stored with silica gel at an even temperature. As seeds are harvested in mid-summer they need to be stored in any case until early winter and if the eliasome, is left intact, can start to grow fungi in storage. It is unknown whether the ants utilize the eliasome immediately they take them underground or is it stored in their pantry with the eliasome intact. The thin coat is probably not used by the ants, (it is difficult to remove) but a hot fire will dry and flake off parts of this coat. I have used a flame (from a blowtorch) to do this, but overheating is a problem and happens quickly. A soak in concentrated sulphuric acid for about five minutes will work as well but I prefer to keep closer to the real thing and I do not like to work with acid. A 10x eyeglass is useful at this stage to check if the skin has been removed adequately – this thin skin is reddish, the nut is black.
To crack the last and hardest coat the seeds need to be brought up to 50 to 60 degC with a dry heat and held there for one hour. A conventional kitchen oven works but is difficult to maintain that temperature accurately. I have a wooden (or cardboard) box with an open bottom and a hole on the top that can be partially closed to regulate the rising hot air provided by a strong incandescent light bulb. An interior shelf that allows the movement of the hot air is needed – a few metal rods (or wooden dowels) to support a dish for the seeds and a thermometer completes the set-up.
If the seeds are taken from the hot box and dropped immediately into water with ice blocks a soft crackling noise can be heard – that of the hard nut shattering yet holding its form though some of the nut will break off entirely exposing the soft seed inside. This step is an optional extra and adds only a few percentage points to the germination rate, so it is not entirely necessary, it merely helps the weaker seeds. The ice water can send the seeds into dormancy, so seeds should be strained after five seconds and dropped immediately into the room temperature primer. I have noted that some seeds (possibly the weaker ones) take several weeks, even a month longer to germinate without any treatment to weaken the outer coat, yet they still germinate. I suspect the pressure needed to break outwards is less than an inward pressure, so perhaps this hot box procedure is not really needed.
Hydrogen peroxide (H2O2) at 1% concentration may be mixed with a drop or two of gibberellin and the seeds should now soak for 24 hours. The H2O2 has an oxygenating effect through the now exposed seed coat with the thin oxygen barrier skin removed.
All this will be for nothing if the attempt at germination is made in summer with its warm days and nights. The temperature must fluctuate by at least 10 deg C which prevails in late autumn/early winter when the cooler nights are longer and the day length shorter. A night/day photoperiod of 16/8 hours. This temperature fluctuation applies as strongly for the hairy seeds of the proteas but less so for the leucadendrons. However as in the case of some of the mimeteses a lower temperature of 5 deg C (a domestic fridge runs at about this temperature) may be required as a cold pulse for a few days after the germination attempt is started, generally after about two to three weeks.
I have noticed that Protea seeds that have germinated a month or two before the shortest day of winter grow on better than those germinating after the shortest day. The growth progression is much slower and seedlings are shorter as the summer days lengthen. This poses the question that the cotyledon (that is the first to emerge above the surface) is more sensitive to the progressively shortening days. My enquiry will be to find if the Proteaceae cotyledon is keyed to a short day to optimise growth stimulants. I will be germinating selected Protea seeds each month before and after the shortest day, and measuring the comparative growths until mid summer.
Placing the seeds in a domestic fridge for 16 hours and then removing them every day for 8 hours is tedious and the domestic fridge is set to run at about 5 deg C which is too low for most seeds and could even send them into dormancy. The warmest setting is also too low; you need the fluctuations to start at about 8 deg C to end around 16 deg C. The trick is to utilize the ambient temperatures of late Autumn/ early winter and then for a few days to place the seeds in the lower temperature for 8 hours in the fridge then removed for 16 hours. Unless your Autumn is kind enough to provide a cold snap.
To force seeds to germinate during the wrong season for various reasons, the primed seeds can be placed in an incubator with set temperature fluctuations and periods. I use petri dishes with a wad of blotting paper to absorb the anti-fungal plus water mix. A converted fridge with two external timer switches, two different internal thermostats, a heating pad (or strong light connected through a dimmer switch) inside and a maximum/minimum thermometer has worked well for me, but I still prefer to use the natural temperature fluctuations – it is cheaper and easier.
Germination naturally varies but count on at least 21 days before the stronger seeds start splitting, radical emergence following and can continue up to 45 days and even beyond. At this point I have found that sowing the germinating seeds individually into deep, small multi cells a better option than others.