in the Seeds of Acanthacea\ 71 



traversed by elevated ridges, which inclose irregular areas, often more or leM 

 quadrangular in form, with a raised point in the centre: on the OOIU 

 surface the woody cells are frequently extended into short, rigid, slight I v- 

 recurved hooks, very different from the elongated membranous hairs whieh 

 occur on the edge. The marginal hairs of J), credits sometimes contain a 

 quantity of granular matter, and the hooks on the disc are somewhat longer 

 than in D.patulus. The seed of D. deject us scarcely seems to differ in struc- 

 ture from those of the two species already noticed, except in having spiral 

 hairs on the border; but the only specimen I have had an opportunity 

 examining was very imperfect. 



In Blechum Brownei the seed is furnished with a narrow whitish border, 

 formed of short, cylindrical, membranous cells, rounded at their ends, entire!) 

 destitute of fibre. These cylindrical cells are arranged in a radiating manner. 

 not appressed like the hairs which compose the border of StrobiloHthes, Dipte- 

 racanthus, &c. On being moistened they become greatly distended by the 

 expanding mucilage within, and ultimately assume the form of wide, blunt, 

 wavy tubes, constructed of an exceedingly delicate membrane, without fibre 

 or any very distinct markings, and frequently terminated by a small club- 

 shaped appendage, looking something like the rudiment of a second cell. 



In a considerable number of Acanthacece the seed is invested with very 

 numerous long, slender, tapering hairs, formed of simple membrane, and pro- 

 ceeding equally from every part of the testa, closely appressed, but expanding 

 in water, without any discharge of mucilage. This structure I have found to 

 be very prevalent in the genus Barleria, having examined nine species without 

 observing a single exception; it also occurs in many species of LepiiagaihU 

 and Goldfussia, in Eranthemum* nervosum, and E. Wightimmm, Phlogacanthus 

 thursijiorus, Hemiadelphis polyspermy and Xeurostachfs tetragonostacln/s. 



In Lepidagathisfasciculata, L.mucronata and LJiyalina, the hairs are much 

 shorter" and blunt-pointed, but" devoid of fibre, and scattered over the whole 

 surface of the testa, as in the majority of the species. Those of L. scarhm 



* A remarkable difference of structure occurs in the seeds of Eranthemum crenulatum, and another 

 species closely allied to E. bicolor; the testa in both is entirely destitute of hairs, and reticulated 

 with anastomosing ridges formed of elongated cells ; in the areas between the derated ndge 8 the cell* 

 are shorter and nearly hexagonal. 



