178 Prof. Dow's Descriptions of two new Genera of the 
Since the preceding observations were in type, I have been favoured by my 
friend Mr, Smith, of the Royal Botanic Gardens at Kew, with a specimen of 
Cunninghamia sinensis, bearing several male catkins, and a full-grown cone. 
A careful examination of this remarkable plant has satisfied me that its proper 
place in a systematic arrangement is among the Cupressineæ, next to Athrotaxis 
and Cryptomeria, to both of whom it is related in a nearly equal degree. In the 
form, structure, insertion, direction, and number of its ovula it agrees entirely 
with the former genus, from which it is principally distinguished by its elon- 
gated aggregate male spikes, and by the addition of a third polliniferous theca. 
The placentary region is crowned with a thin, narrow, minutely toothed border, 
clearly of the same nature with the remarkable toothed organ, which I have . 
described as the pericarpium in Cryptomeria, and which, singular as it is, can 
no longer be regarded in any other light than as an excessive development of 
the placentary region, and what I have described as a bracte is really the apex 
ol the pericarpial leaf. The enlarged placentary region, and the erect ovula, 
are characters amply sufficient to separate Cryptomeria from Cunninghamia, 
in which the polliniferous thecze are fewer, and. altogether free. "The striking 
resemblance, both in form and structure, of the antheriferous scales to those of 
the female spike, and also to the bractes and leaves, clearly show that they are 
all modifications of one and the same organ. In all the three genera above- 
mentioned the antheriferous thecæ bear an evident relation to the number of 
the ovula, the latter apparently originating in all cases from the upper, and 
the former from the inferior surface of the modified leaf. The direction of the 
ovula, which in all cases are atropous, is evidently a character of no more than 
generic value in this family. 
March 6, 1839. 
EXPLANATION OF THE PLATES. 
| Ta DE 
Fig. 1. Cryptomeria japonica. :* 
a. Antheriferous scale, front view, showing the five thecze. 5. Ditto, 
back view; both magnified. «c. Scale of cone, with its bracte, back 
