120 ON SEEDLINGS 



and the raphe superior or lateral. The embryo is minute 

 The seeds are globose or reniform, smooth (Sanguinaria, 

 Chelidonium, Hypecoum, Adlumia, &c.) or alveolate (Papaver, 

 Meeonopsis, Glaucium, Kcemeria, &c.). 



One species of Corydalis presents us with an interesting 

 case of what I have proposed to call Heterocarpism. 1 That is 

 to say, the plant produces two kinds of fruit, one somewhat 

 flattened, short and broad, with rounded angles, the other 

 elongated, hooked, and shaped like a shepherd's crook with 

 a thickened staff. The hook perhaps serves for dispersion. 

 It is possible that the alveolate surface of the seed may serve 

 the same purpose the depressions imprisoning, as it were, a 

 certain quantity of air, and thus lowering the specific gravity. 



In the Poppies the seeds are so situated that they can 

 only leave the capsule if it be swung or jerked by the wind. 

 In the case of trees, even seeds with no special adaptation 

 for dispersion must be often carried by the wind to some 

 distance, and to a certain, though less extent this must hold 

 good even with herbaceous plants. It throws light on the, at 

 first sight, curious fact that in so many plants with small 

 heavy seeds the capsules open not at the bottom, as one 

 might perhaps have been disposed to expect, but at the top. 

 A good illustration is afforded by the well-known case of the 

 common Poppy, in which the upper part of the capsule 

 presents a series of little doors through which, when the 

 plant is swung by the wind, the seeds come out one by 

 one. The little doors are protected from rain by overhanging 

 eaves, and are even said to shut of themselves in wet weather. 2 



Cotyledons. There are at least four distinct types of coty- 

 ledons in the Order, namely, linear, broadly oblong, bifid, and 

 ovate. The first is the most prevalent and characteristic, and 

 may be seen in Platystemon, Papaver, Argemone, Meeonopsis, 

 Glaucium, Eoameria, Hypecoum, and Fumaria. In Papaver vil- 

 losum var. Heldreichii (fig. 145) they are oblong-linear, obtuse, 

 entire, sessile, one-nerved, and glabrous. Others vary from this 

 in being more slender, and more distinctly linear, and some are 

 narrowed to a petiole as in P. spicatum and occasionally in 

 Meeonopsis cambrica. The midrib is not always discernible 



1 Flowers, Fruits, and Leaves, 5th edit. p. 90. 2 Ibid. p. 64. 



