CARYOPHYLLE/E 211 



Brachystemma and Sphaerocoma, and in some species of 

 Acanthophyllum and Stellaria, while Queria as above men- 

 tioned is one-ovuled and one-seeded. 



The form of the embryo in reniform seeds is well shown 

 in the vertical section parallel with the embryo of Cerastium 

 arvense (fig. 199). The seeds are small, reniform, laterally 

 compressed, with very unequal ends, the larger one containing 

 the cotyledons, and the smaller one the radicle of the embryo. 

 The testa is densely covered with small protuberances an 

 extremely common occurrence amongst the reniform seeds of 

 this Order. The embryo is curved and peripheral, but sur- 

 rounded on the back with a thin layer of endosperm, although 

 it is usual in other seeds of this type for the embryo to lie 

 in immediate contact with the testa. A globular mass of 

 floury endosperm lies in the sinus of the embryo on the ventral 

 aspect of the seed. The cotyledons are linear, scmiterete, 

 obtuse, incumbent, and lying in the narrow plane of the seeds ; 

 the terete radicle tapers gradually to a blunt point, and is 

 somewhat shorter than the cotyledons. A small indentation 

 at the hilum seems the only thing hindering the embryo from 

 making a complete circuit of the seed. 



With the above type the following agree in all main par- 

 ticulars, namely, Gypsophila repens, G. Eokejeka, Saponaria 

 officinalis, S. orientalis, S. Vaccaria, Silene gallica, S. Villarsii, 

 S. noctiflora, S. tatarica, S. depressa, Cucubalus bacciferus, 

 Lychnis diurna, L. vespertina,the species of Stellaria, Arenaria 

 graminifolia, and others. A slight variation is met with 

 in Lychnis Githago, where the thicker end of the seed contains 

 the radicle and the thinner one the cotyledons ; the reverse 

 is usually the case when the seed is not of the same thickness 

 throughout. A striking modification occurs in the species of 

 Holosteum which have their ovules very much curved and 

 folded so that one half lies against the other. The morpholo- 

 gically apical end containing the radicle is very narrow and 

 forms a keel adnate to the face of the other half, which is 

 much compressed. The cotyledons are incumbent and brought 

 so close to the radicle that they nearly or quite touch it. There 

 is little or no endosperm between them, but a considerable 

 thickness of it on each side of the cotyledons so that the latter 



