SECT. II 



PHANEROGAMIA 



517 



Lastly, a structure known as the arillus must be mentioned, 

 which usually stands in relation to the distribution of the seeds. It 



Fig. 482. — A, Seed of Hyoscynmus niger, sliowing 

 the dicotyledonous embryo embedded in the 

 endosperm ; B, seed of Elettaria Cardamomum, 

 enveloped by a thin aril ; the white, mealy 

 perisperm next to the seed-coat encloses an 

 oleaginous eu'losperm (shaded), in which the 

 monocotyledonous embryo lies embedded. 

 (After Berg and Schmidt.) 



Fig. iS3.—C'ipsrl!a h>ns<i jxuftoris. A, Longi- 

 tudinal section of a ripe seed ; h, hypoeotyl ; 

 f, cotyledons ; v, vascular bundle of the 

 funicle (x 26); B, longitudinal section of 

 the seed-coat after treatment with water ; 

 e, the swollen epidermis; c, brown, strongly 

 thickened layer ; *, compressed layer of 

 cells ; a, the single persisting layer of 

 endosperm cells containing aleurone grains 

 (X 250). 



arises as a succulent and usually brightly coloured outgrowth from 

 the funicle. It grows up around the ovule and ultimately comes to 

 invest the seed more or less completely (Fig. 485). An outgrowth 



nr 



Fio. 484. — .4, Seed of Papaver Rhoca'i; h, 



the hilum ; B. seed of Corydalis oc/ini- 



Intca; m, micropyle ; c, caruncula ; Fio. 485.-^1, Myristica fragrans, seeA from which the 



arillus (tu) is partly detached B, Myristica avfjentea, 

 seed after removal of the arillus; f'h, chalaza ; r, 

 raphe ; /(, hilum. (After Warburg. J nat. size.) 



C, seed of CheUdonium. majus'; D, seed 

 of Nymphai'a alba with its arillus. 

 (After DucnABTRE.) 



in the neighbourhood of the micropyle, which is found in the Euphor- 

 biaceae, is termed a CARUNCULA. (Fig. 484). 



The effect of fertilisation Is not only seen in the macrosporangia 

 but extends to the macrosporophylls or carpels. The structures of 



