38 BULLETIN 1082, IT. S. DEPARTMENT OF AGRICULTURE. 
At Bellingham, Wash.., broken tulips have not been grown, and 
the stocks, many of which have been grown there for 15 years, num- 
bering between 250 and 300 varieties, have not broken. 
Any self-colored tulip (and all tulips grown from seed are self- 
colored) may become broken. The statement is sometimes made 
that the single early tulips do,not break, but this is true in the florist's 
sense only. These break just as truly as the others, but they give 
in the breaking no spectacular patterns such as are found in other 
groups; on the contrary, the brilliancy of their floral coloration as well 
as their general vigor is reduced. Consequently, the broken plants 
in this group are rogued out of the stock. 
The cause of breaking in tulips has not been demonstrated, neither 
has it been investigated until recently with the idea of its disease 
origin in mind. Nor for that matter has the real cause of mosaic 
diseases in other plants been demonstrated, although extensively 
studied. The essentials of com munic ability, effect on the host, 
carriers, and preventive measures are well worked out, however. 
As in tobacco, it is probable that here again the aphis is the main 
carrier of the disease. Fortunately the aphids have never been 
numerous in the bulb fields at Bellingham, Wash. 
With this information before him the bulb grower should consider 
carefully before he attempts to introduce broken stocks into his 
plantings. It is known that the disease is communicable to self- 
colored stocks. There is, consequently, grave danger of his self- 
colored stocks becoming ruined if broken stocks are introduced, 
for when once broken they can be sold only as mixed tulips. The 
production of bulbs of these mosaic varieties should not be attempted 
except at safe distances from the regular self-colored stocks. 
A peculiar trouble sometimes occurs in tulip bulbs when grown 
under adverse conditions which has caused growers concern because 
interpreted to be a disease. It manifests itself in the form of an 
imperfectly filled bulb coat. The base of the bulb may be quite 
normal and well filled but reduced in size, but the tip may be empty 
and wrinkled, as is well brought out in Plate VII, Figure 1. This 
condition has been observed in many varieties on the Pacific coast 
when planted shallow and late on very light soil that dried out too 
quickly in the spring. 
WHY SOME VARIETIES ARE CHEAPER THAN OTHERS. 
It is not necessary to discuss values in novelties or new varieties 
of which only limited stocks are available. Here the law of supply 
and demand and a desire for the new govern, as in any other com- 
modity. 
Leaving aside entirely the facts of actual merit, popularity, and 
consequent general demand, there are some varieties which can 
