192 Proceedings of the Royal Irish Academy > 
rather be considered as indications of an attempt to draw its Order 
nearer to its relatives amongst other families. Thus, the position of 
-the Heath Order among the Corolliflorse seems somewhat ano- 
malous. This sub-class contains dichlamydeous plants, in which 
the stamens are mostly inserted on the corolla, or epipetalous. The 
heath- worts are an exception, seeing that they have their stamens free. 
The case of this plant is, then, that, being an exception to an excep- 
tion, it harmonizes the Ericaceae with other families of its sub-class. 
Eoth in Primulacese and Plantaginaceae occur polypetalous corollas, 
with epipetalous stamens. Thus, the division of the corolla in the 
present plant not only brings it into some resemblance with Calluna 
and with Leiophyllum (genera of heath- worts in which the corolla is 
deeply divided), but also it assists, with the epipetalous stamens, to 
bring the heath- worts themselves into harmonious relationship with 
the other Orders of the sub-class Corolliflorse. 
XXX. — Addition's to the Flora of the Tenth Botanical Distkict, 
lEELAifD. By G. SiGEESON, M.D. (With Plate XYIl., Science). 
[Read June 12, 1871.] 
At the suggestion of Professor Babington, in 1859, Ireland has been 
divided into twelve botanical districts. The counties of Tyrone, Fer- 
managh, Monaghan, Cavan, and Armagh, taken together, constitute 
the tenth botanical district. It is bounded on the north-west by 
Donegal, the eleventh district, and on the north-east by the twelfth 
district, formed of the counties of Londonderry, Antrim, and Down. 
The additional plants which I have found for the Flora of the tenth 
district were all met with in its north-western angle, in the latter 
part of the summer of 1869. This corner of Tyrone, bounded on the 
north and west by the twelfth and eleventh districts, is a markedly un- 
dulating country. The prevailing rocks are limestone and slate. In 
the particular district which I examined the highest mountain, Owen- 
reagh, is 1360 feet above sea level, and the lowest ground is the floe bog 
of Leckpatrick, which varies from forty to sixteen feet above sea level, 
according to the calculations of the Ordnance Survey. The river Foyle, 
running northwards from Strabane to Derry, passes through a wide 
valley, which admits the cold north winds without check ; but from the 
margin of the valley to Owenreagh there are many hills, hollows, and 
mountain glens, well sheltered, and perceptibly warmer. J^'evertheless, 
cereals are reaped in the fertile valley of the Foyle before similar crops 
have completely ripened in the Antrim portion of the adjoining twelfth 
district. 
In the subjoined list I have mentioned a few plants which have 
been already recorded from this district of five counties, because they 
have not been given for the county Tyrone, and because they are 
