194 
CONTRIBUTIONS TO BOTANY. 
pear to have been noticed ; they are serrato- denticulated, and 
each tooth is terminated by a distinct stipitate gland, as I have 
noticed in some species of Cyrta. The tree scarcely exceeds 
8 or 10 feet in height — little more than half the size of H. te- 
traptera, and is more frondose. Its leaves are from 3^-4 inches 
long and 2^-2| inches broad, upon a petiole of 6 or 7 lines in 
length. Its peduncles are not articulated with the calyx •, they 
are 6 lines long; the calyx is 1 line; the petals are 10 or 12 lines 
long and 3-4 lines broad, tapering towards the base. The 
stamens are 8 or 9 lines long ; the filaments broad and mem- 
branaceous, quite glabrous ; the anthers 2 lines in length : 
in the bud the filaments adhere by their margins for their whole 
length ; but when the flower is expanded they are free nearly to 
the base, afterwards quite unconnected, and also unattached to 
the petals. The upper free moiety of the ovary is conical, to- 
mentose, and continuous with the style, which is slender, pu- 
bescent, and 9 or 10 lines in length. It frequently occurs that 
the style becomes deeply trifid, being divided for a third of its 
length into three fine threads, — a circumstance that does not 
occur in H.tetraptera, nor is it anywhere recorded of this species. 
The placenta rises to near the middle of the cell of the ovary ; 
and it bears a greater number of ovules than the former species. 
The fruit has only two opposite wings, the others being almost 
obsolete; it measures 1^ inch in length and | inch in breadth : 
the nut is fusiform, as in the other species. The parts of the 
flower, though generally 4-merous, are very frequently 5-merous, 
so that this character alone ceases to form a distinction between 
Halesia and Pterostyrax *. 
3. Halesia parviflora, Mich. FI. Bor. Amer. ii. 40 ; Lindl. Bot. 
Reg. tab. 952 ; A. DC. Prodr. viii. 270. — In Florida et 
Georgia. 
7. Pterostyrax. 
We have no knowledge of this genus beyond the description 
of Zuccarini in SiebePs ‘ Flora Japonica,^ where the typical 
species is figured. Having seen a specimen in flower in Sir 
William HookePs herbarium, I am enabled to speak of it with 
more confidence. The character, as given by Zuccarini, agrees 
well with the structure of the flower in Halesia, differing in no 
respect except in the pentamerous disposition of its parts ; but 
even that distinction I have shown to be of no value, because 
we sometimes meet with five petals in Halesia, while in Ptero- 
* Anahiiical figures, showing the floral and car])ological structure in 
these two species, will be given in Plate 31. 
