52 DR. THOMSON ON SEEDS OF BAERINOTONIA AND CARETA. 



at the extremity from which the stem is afterwards developed, the 

 surface i^ perfectly uniform. 



Eoxburgh's MSS. drawings in the library of the Calcutta Bo- 

 tanic Garden contain excellent figures of the germinating seeds of 

 Careya arhorea and Ba/rringtonia racemosa. My examination of 

 the germination of Careya has confirmed Eoxburgh's observations, 

 and I found that, allowing for difierence of size and shape, the 

 germination of Barringtonia acutangula, the species I examined, 

 is exactly like that of B. racemosa, as figured by Eoxburgh. 



In all, the only appearances of foliar organs are a few minute 

 scales surrounding the growing point, which is gradually elon- 

 gated into the ascending axis. On this axis the earlier leaves are 

 quite rudimentary, and true leaves are not developed till it has 

 become one or two inches long. 



A longitudinal section of a germinating plant shows that the 

 central body is continuous with the pith, and the superficial body 

 with the bark, as Eoxburgh has long ago stated. It further shows 

 that the vascular layer, which separates the two, is continuous 

 both upwards and downwards with the ligneo-vascular cylinder of 

 the stem and root. 



It is thus evident : 1. That the embryo of BarringtoniecB is ex- 

 albuminous. 2. That the cotyledons are rudimentary. 3. That the 

 embryo is an axial organ, consisting of pith, woody layer, and bark. 

 4. That the plumule, at best almost without scales, is developed 

 into a stem, while the opposite extremity elongates into a root. 



In examining nearly a hundred germinating plants of Careya 

 arhorea, I found that in a considerable number (eight or ten 

 instances) the primary axis died off, and the stem was continued by 

 a bud springing from the axil of one of the minute scales. In one 

 instance this took place so close to the embryo as to be apparently 

 in the axil of one of the first pair of scales, or rudimentary coty- 

 ledons. 



In describing the seeds of Garcinia and Xanthochymus, Eoxburgh 

 states that their structure is quite like that of the seeds of Careya 

 and Barringtonia, except that the central portion (which he calls the 

 embryo) is very slender, and that the permanent root proceeds 

 from the base of the plumule, while that from the opposite end of 

 the embryo soon perishes, or remains slender as compared with the 

 other. 



Such adventitious roots are of common occurrence also in 

 Careya, so that the difference is even less than Eoxburgh sup- 

 posed. Circumstances prevented my examining germinating seeds 



