in the Seeds of Acanthaceae. 7"> 



walled hexagonal cells. In H.Wallichii these tubercles are crowned with i 

 ring of very small deflexed hooks, which are ranting in II. purpurea. 



Gendarussa Neesiana, G.quadrifaria, G.tranquchuriensis, G.orixentU, Ad- 

 hatoda Betonica, A.trinervia, A.argyrostachya, Rhinacanthus communis, Rungiu 

 IVightiana, R.origanoides, R. parviflora, Peristrophe pubigera, P. moniunu. 

 P. speciosa, P. lanceolaria. — Very little difference of structure is to be observed 

 in the seeds of the above species, which, until the subdivision of that genus by 

 Professor Nees von Esenbeck in his revision of the Acmnthacem, wet* all placed 

 together under Justicia. They are for the most part small, compressed, tri- 

 angular or cordate, with a loose spongy testa, consisting of nearly hexagonal 

 cells with thick side-walls, and so much crumpled as to form numerous closely 

 crowded hollow tubercles. The tubercles, which occupy tin- entire surfac. 

 the seed, are usually blunt and rounded at their extremities ; but in Genda- 

 russa tranquebariensis and oriooensis they are prolonged into decurved points. 

 These characters are less conspicuous in the genus Peristrophe : the seeds of 

 P.pubigera and P.montana differ little, except in their larger size; but in 

 P. speciosa and P. lanceolaria the testa is thinner and more even ; the tuber- 

 cles also are very small and less numerous in P. speciosa, whilst in P. lanceo- 

 laria they are almost if not altogether wanting. 



These observations having been chiefly made on such seeds as could be 

 obtained from dried specimens, many of them in an unripe or imperfect 

 condition, it is scarcely possible that I should in every instance have avoided 

 mistakes : it would, however, be a great pleasure to me could I hope that this 

 very imperfect view of the subject might prove the means of leading to a more 

 accurate investigation of the seeds of this interesting family; and I trust that 

 whoever may pursue the subject further, will make allowance for the difficulty 

 of attaining to perfect accuracy with such materials. 



EXPLANATION OF TAB. VI. 



Fig. 1. Fasciculate hair from the testa of a species of podium [A. spicatum, Del.?), 

 collected in Upper Egypt by Mr. Holroyd. 

 2. Portions of single tubes of the same, more highly magnified. 



l2 



