THE AMERICAN BOTANIST. 119 



Poisonous Yams. — Yams (Dioscorea) are among the 

 chief foods of the tropics and it is a matter of interest to 

 learn that every variet}^ contains a poisonous alkaloid 

 called dioscorine which acts as a paraWzant of the nervous 

 system. Fortunately this alkaloid is removed by boiling, 

 and as yams are not eaten raw, no ill effects are experi- 

 enced. 



The Citrange, Tangelo and Plumcot.— Recent exper- 

 imenters, not content with simply hvbridizing their plants, 

 have insisted on h3'bridizing their names also. Thus w^e 

 now have the plumcot, a cross between the apricot and 

 plum, the tangelo, a cross between the tangerine orange 

 and the pomelo or grape fruit, and the citrange a cross 

 between the orange and an inedible species called the tri- 

 foliate orange (Citrus). It is well known that squashes 

 and pumpkins planted too near together form natural 

 hybrids. Now, the question is, would the hybridizers call 

 these fruits squakins ? 



Pollination of Water Plants. — Field botanists are 

 familiar with the general method of pollination in water 

 jjlants like the eel-grass ( Vallisneria) but the details do not 

 seem to be so well known. In the Botanical Gagette for 

 January, R. B. Wylie in discussing the morphology of the 

 ditch moss (Elodea Canadensis) describes its method of 

 pollination very fully. This plant grows under water and 

 its pistillate flowers reach the surface by means of a great- 

 ly elongated floral tube, the ovaries being sessile and some 

 distance under water. The staminate flowers have no 

 lengthened tube and at maturity break loose from the 

 plant and rise to the surface where they shed their pollen. 

 The special interest that attaches to this feature is the fact 

 that just as the pollen is ripe, the plant gives off oxygen in 

 sufficient quantities to fill the flower and keep the water 

 awaj^ from the pollen. Even before the flower rises to the 

 surface the pollen may begin to be shed in the bubble of 

 oxygen. The gas also aids the flower to rise to the sur- 

 face. At the surface the bubble at once disappears, the 

 sepals snap backward, forming a three-parted float. At 



