PLANTS FROM WHICH SENNA-LEAVES ARE OBTAINED. 359 
2. From Mecca, by way of Alexandria, the well known 
narrow-leaved Senna. 
3. From Syria, by way of Aleppo, the obovate leaves. 
4. From Tripoli, the mixture of two species, first dis- 
covered by Nees and myself. 
5. From the East Indies, the narrow-leaved wild-grow- 
ing Mecca Senna, and the Tinevelly Senna grown from 
seeds. 
The description of Alexandrian senna is found in every 
class book. But as it contains the three principal species of 
all officinal senna-leaves, it is important that I should give 
their botanical analysis and their special diagnosis ; and 
also examine the prevailing opinions respecting them. 
Having, during my long residence at Trieste, bestowed 
great attention upon this subject, and afterwards received 
the communication of my lamented friend Sieber, and seen 
with great interest the beautiful specimens of Ehrenberg, 
in Berlin, where I was assisted by the advice of my friend 
Hayne, and having lately examined in Paris Delile's plant 
in company with Delile himself, 1 felt the importance of also 
inspecting Forskal's plants in Copenhagen. My late friend 
Professor Schumacher, who resided there, had for some 
time been engaged with the examination of the same sub- 
ject, and we examined together the specimens from For- 
skal's own hand, contained in the herbarium of Vahl. 
There we found Cassia Senna, identical with the plant of 
the same name, which I had seen in the herbarium of Lin- 
naeus ; further C. angusiifolia, Vahl, with the inscription 
C. lanceolata, in Vahl'sown hand. This I found identical 
with that in Wildenow's Herbarium, in Berlin. The real 
lanceolata of Forskal, ho wever, we did not then find. During 
my last journey, I looked over the different species of cassia 
in the British Museum, and again found that the English 
are the best conservators of botanical treasure, for there I 
found, at last, to my great astonishment, what I had so 
much missed at Copenhagen, namely, a perfect specimen, 
