98 OBOHIDACEAE. 



specimen in the herbarium of Columbia UniTersity, collected by John I. and Alice 

 E. Northrop, on Andros Island, in May, 1890, no. 543, doubtfully determined by Mrs. 

 Northrop as 0. stilvestre Lindl., is also this species ; it was also referred to O. 

 sylvestre by Cogniaux. The plant recorded by Baton and Setchell, and also by 

 DoUey, from Abaco, collected by Herrick, is apparently this species. 



This orchid is related to Oncidium sylvestre Lindl., but the longer leaves, 

 smaller flowers, and the differences in the lip at once distinguish it. In 0. sylvstre 

 the leaves are not over 4 cm. long, the flowers are fully twice the size, and the lip 

 has the lateral lobes very small ; in O. tahamense the lip is as broad across the 

 lateral lobes as it is at the apex. 



3. Oncidium lucayjlnum Nash, sp. nov. 



Plant witli short compressed leaves and a few-flowered raceme. Leaves 

 4r-Q, crowded at the base, curved, spreading, acute, compressed, acutely angled 

 on the back, channeled on the upper surface, wrinkled on the upper margins, 

 smooth and glabrous, 1-1.5 em. long and about 3 mm. wide; scape smooth and 

 glabrous, with a few scattered ovate acute appressed scarious scales 3-4 mm. 

 long; flowers on pedicels 5-7 mm. long; dorsal sepal oblanceolate-cuneate, 

 acutish at the apex, narrowed toward the base, 7 mm. long and 2-2.5 mm. 

 wide, the margins repand; lateral sepals united into a concave 2-nerved oblance- 

 olate-cuneate body which is 2-toothed at the apex, the teeth rounded and about 

 0.75 mm. long, about 8 mm. long and 2.5-3 mm. wide; petals lyrat€-ovate, 

 acute at the apex, abruptly narrowed below the middle into a claw about 2 mm. 

 long and 1.5 mm. wide, 8 mm. long and 3-3.5 mm. wide, undulate on the 

 margin; lip adnate to the column up to its wings by a bi-lamellate process, 

 8 mm. long and 7 mm. wide, sessile by a rounded or truncate base, 3-lobed, the 

 lateral lobes 1.5-2 mm. long and 1.5 mm. wide, somewhat reflexed, rounded or 

 a little acute at the base, merging into a hemispherical somewhat toothed 

 isthmus which joins them to the middle lobe, the middle lobe flabellate, on a 

 triangular claw, round-truncate and apieulate at the apex, irregularly lobulate 

 on the margins, the crest of 3 lobes, the lateral divaricate, separated by a 

 rounded protuberance, the middle lobe the largest and again 3-lobed; column 

 3-3.5 mm. long, the wings semiovate, rounded at the base, acute at the apex, 

 irregularly lobed and extending somewhat beyond the sunxmit of the column. 



Type, in the herbarium of Columbia University, collected by John I. and Alice 

 E. Northrop, at Fresh Creek, Andros Island, June 10, 1890, no. 6j7. Eesembles O. 

 variegatum considerably, but the sepals are nearly as long as the lip, and the 

 middle lobe of the lip flabellate while in O. variegatum the sepals do not exceed one 

 half the length of the lip which has the middle lobe reniform and sessile. Referred 

 by Cogniaux to 0. Leiboldi Rchb. f. 



Oncidium variegatum Sw. is recorded by Cogniaux as collected on Andros 

 (Northrop 587) but our specimens of this number appear to be 0. lucayanum. 

 We have fruiting specimens of apparently the same plant from Abaco and 

 Great Bahama. 



A small Oncidium, collected on Cat Island, died before flowering. 



Subclass 2. DICOTYLEDONES. 



Embryo of the seed with two cotyledons (in a few genera one 

 only), the first leaves of the germinating plantlet opposite. Stem 

 exogenous, of pith, wood and bark (endogenous in structure in 

 Nymphaeaceae) , the wood in one or more laj^ers surrounding the 

 pith, traversed by medullary rays and covered by the bark. Leaves 

 usually pinnately or palmately veined, the veinlets forming a net- 

 work. Parts of the flower rarely in 3 's or 6 's. 



Dicotyledonous plants are first definitely known in Cretaceous 

 time. They constitute between two-thirds and three-fourths of the 

 living angiospermous flora. 



