contains, but also from the fact that not a single unwholesome plant is found 

 in it. Many species form well known and excellent articles of food, as the 

 cabbage, turnip, radish, watercress, etc. Some of our worst weeds, however, 

 most of which have been introduced into Canada, belong to this family. The 

 characters of the family are easily recognized. The flowers are regular, com- 

 posed of four free sepals and four free petals, arranged in two opposite pairs 

 and forming a cross-shaped flower, from which the whole family takes its 

 name, Crucifera;. The flowers are borne on footstalks (pedicels), aud clust- 

 ered at the tips of branches which gradually elongate, forming long, upright 

 racemes, with, often, fully-formed and even ripe pods below, before the top- 

 most flowers have opened. When ripe the seed pods, which are of various 

 shapes, in nearly all instances, consist of two outside walls separated by a 

 thin white partition, to the two sides of which the seeds are attached. The 

 seeds are, as a rule, small and very numerous, Their surface is usually 

 rather dull, more or less granular, and many, when placed in water, develop 

 gelatinous hairs and mucilage, by which, when they dry, they remain 

 attached to passing objects or adjacent surfaces. This constitutes an import- 

 ant factor in their distribution. The quantity of mucilage varies. On some 

 seeds it remains after drying as a covering of hair-like points or threads. 

 The seed-coat is generally thin and close-fitting, the shape of the embryo 

 plant showing plainly through it. The position taken by the folded up 

 embryo inside the seed is often a great help in identifying the seeds of weeds. 

 The seed leaves and radicle inside the seeds of crucifers take one of four 

 characteristic positions : 



1. Accumbent, when, the radicle lies along the edges of the seed leaves, 

 as in Stinkweed, from a Latin word accumbo, meaning to lie at the side. 



2. Incumbent, when the radicle lies down the back of one of the seed 

 leaves, as in Shepherd's-purse, Common Pepper-grass and Hare's-ear Mus- 

 tard, from a Latin word incumbo, meaning to lie on the back. 



3. Oblique, when the radicle lies slantingly across the edges of the seed 

 leaves, as in the Prairie Wallflowers. 



4. Conduplicate, when the radicle lies on the back of one of the seed 

 leaves and these are folded sideways over it, as in the Mustard, Eadish, etc. 



Many of the Crucifers have in the roots, stems or seeds recognizable 

 odours or flavours, which help in identifying them. The leaves and stems of 

 many bear small star-shaped hairs. The best known or most noxious mem- 

 bers of the Mustard family are treated of separately and figured, others 

 which might be confounded with them will be referred to in the text, and 

 the chief differences pointed out. 



Closely allied with the Mustard family is the Caper family (Cappari- 

 dacea?), which has some important characters in common with it, such as 

 cross-shaped flowers, seeds in pods, but these without partitions, and often 

 having acrid or pungent juice. The chief differences between the two families 

 are that in the Mustard family, four of the six stamens are long and two 

 short, while in the Caper family all six are equal, and the pod of the former 

 two-celled, being divided by a thin partition across the middle. The 

 curious seeds [Plate 55, fig. 47 natural size and enlarged 4 times] of the 

 ENTIRE-LEAVED SPIDER-FLOWER, Cleome integrifolia, T. & G., of this family 

 are sometimes found in western wheat. These seeds are rounded-wedge-shape 

 or elongated-kidney-shape, with a deep curved groove running up each face 

 two-thirds of the way to the top from just above the sharp-pointed base 

 Ihese seeds, when ripe, are dark brown, roughened with pale, scurfy ex- 

 crescences; the dried unripe seeds a-re yellowish. 



2a w. 18 



