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131 
threshed when convenient. In threshing, the difficulty is to get the seed out of the flower and the pod; 
the flower itself readily detaches from the flower-head as its pedicel is brittle. If a shelling machine 
is not at hand, repeated threshing alternated with winnowing is necessary to extract the seed and 
remove the debris and pods. With each threshing the quantity of seed obtained diminishes; the 
operation must usually be repeated about a dozen times to secure all the seed, 
This is excessively troublesome work and almost impossible in damp weather as the flowers 
absorb moisture from the atmosphere and become quile spongy. Threshing is easier in winter when 
the weather is cold and dry; if delayed till the following summer, the flowers can be dried in the 
sun, A very good plan for extracting the seed when il is dry, consists in passing the flowers through 
a pair of millstones from with the hopper has been removed to allow hand-feeding. The clover-rubber 
is a very useful instrument, but it often removes the radicle of the embryo, thus destroying the ger- 
minating power. When such a seed is set, the cotyledons swell and fall asunder. The most perfect 
apparatus for freeing the seeds from the pods is the clover shelling machine. Many forms are in the 
market: that of Carrow of Prague is one of the best. All these machines are very expensive. 
If the clover contains a large proportion of ribgrass (Plantago lanceolata), it is advisable to remove ; 
this impurity by the sieve before shelling the seed. After shelling, ribgrass cannot be cleaned out, as 
the seeds are almost of the same size as those of red clover. Threshing, sufficient to remove the seed 
of ribgrass from their capsules, only breaks up the clover heads into flowers; at this stage, cleaning is 
easy, as ribgrass seeds are much smaller than clover flowers. By this mode of procedure other weeds, 
especially docks (Rumex obtusifolius, L., and pratensis, “Mertens and Koch) are eliminated. In Emmen- 
thal, where ribgrasses and docks abound in the deep soil, this plan is usually followed. Such cleanings 
consist almost exclusively of the seeds of ribgrass, a small quantity of dock and a very few seeds of 
clover which have been threshed from the flowers. 
Hini reckons the yield of seed per acre at 170 to 300 Ibs., Krafft at 300 to 450 Ibs., Sprengel Yield of seed. % 
at 350 to 500 Ibs., Langethal at 200 to 400 Ibs. or more, and Werner at 250 to 440 Ibs. In 
Flanders, Schiwerz estimates the average yield at 300 Ibs. per acre. 
The dodder (Cuscuta Trifolii, Bab. or Cuseuta eptthymum, 
Murr.) is an impurity unfortunately foo common, This dreaded para- 
Impurities. 
site often causes great havoc among clover crops. b } ‘a 
About 90 per cent of thejseed of Silesian and Austrian clovers is mlested by Fig. 55. 
dodder, unless the seed has been specially cleaned. Many attempts have been Dodder. 
Cuscuta Trifolit, Bab. 
made to devise a machine which will remove the seed of this parasite. Fellen- (see ¢. epithymum, Murr.) 
berg of Hofwyl first invented and used such a machine, about the beginning Seed, natural size. 
J . b, The same, X 12—15. 
of this century. Walz of Hohenheim followed his example and now there 
are many makers. Long experience has convinced us that the machines made at Herisau are the best. 
Dodder-seed is usually smaller than that of red clover. The skin is pitted and has one or two flat 
surfaces, The embryo is spiral and without cotyledons. The following percentage of samples of red 
clover seed examined at the Swiss station contained dodder: — 
1877/78 46.5 °/o of the total samples examined 
1878/79 CoC a ae A . 
1879/80 4qUh nS h q 
1880/81 VET hy Lee, c ‘ 
1881/82 Ae ’ F 
Probably the better qualities of seed were sent for analysis; the worse kinds would usually be 
kept back. From these results, it is clear, that, in Switzerland, the proportion of red-clover seed con- 
(aining dodder is diminishing year by year. 
The impurities most abundant are ribgrass (Plantago lanceolata, L.) and dock (Rumea 
obtusifolius, L.); sorrel (Rumesx acetosella, L.), selfheal (Prunella vulgaris, L.), bristle- 
