PIT'IIER TREATMENT OF THE GENUS CASTILLA. 277 



So far Castilla nicoyensis is reported from the peninsula of Nicoya only, but 

 the probability is that it will be found all along the coast of the Pacific, from 

 Nicaragua to Panama. It is a good rubber producer, the milk being particularly 

 abundant toward the end of the dry season, and to this fact is due its almost 

 complete extermination in the western forests of Costa Rica. Besides being met 

 with in widely isolated clumps in the forests of Nicoya, Guanacaste, Savegre, 

 and the Diquis Valley, there are several small plantations of this species scat- 

 tered in the first two districts and around Puntarenas and an extensive one in 

 the "hacienda " of Dr. J. P. Valverde, near Las Canas, on the southwestern 

 slope of the volcano of Tenorio. 

 10. Castilla elastica Cervantes, Gac. Lit. Mex. Suppl. 1794. 



Plate 43. Figure 54. 



A large tree, attaining 20 meters and over. Young twigs densely covered 

 with yeilowish or grayish hair. 



Mature leaves rather large. Petioles 1 to 2 cm. long, thickly clad with 

 grayish, brownish, or yellowish hair. Leaf blades 25 to 40 cm. long, 10 to 15 

 cm. broad, oblong-lanceolate or slightly lyrate, more 

 or less deeply cordate at base, acuminate, rough, 

 sparsely hairy and dark green above, velvety and 

 paler beneath: midrib and primary veins (the latter 

 alternate, 17 to 20 on each side of the first) little 

 conspicuous and pubescent on the upper face of the 

 leaf, prominent, neatly anastomosed and hairy be- 

 neath; margin obscurely sinuate, with tufts of hairs 

 between the sinuses." Stipules caducous, small (5 

 to G cm. long, 2 cm. broad), hairy outside, smooth 

 and purplish inside. Fig. 54.— Floral details of 



Receptacles of the primary male inflorescence Castilla elastica. a, 



caducous, stipitate. 1 to 1.5 cm. long, 2 to 2.5 cm. Cluster of stamens, pri- 



. . . ... . , . mary inflorescence. 1 and 



broad, almost uniformly in clusters of 4 (bigeminate), 2 helu „ al)norma i forms . 



covered outside with 6 or more imbricate rows of b, isolated stamens, one 



small (about 3.5 mm. long, 3 mm. broad), lanceolate, with bracteole; c, style 



obtuse scales free at the tip ; lobes flabellate, refiexed, wit , h * W J° * tl s m * B ; a > 



style with three stigmas. 



and diversely plicate and distorted at time of anthesis. 0_ rf Scale 3. 



Stipes 1 to 1.5 cm. long, with a whorl of small, ovate- 

 acuminate bracts at the base and a few more higher up. Interstamlnate bracts 

 numerous, shorter than the stamens. Stamens 2 to 3 mm. long, inserted side- 

 wise, either singly or in clusters, along dichotomous, radial, foliaceous, diversely 

 shaped crests; filaments flattened, 1.5 to 2.5 mm. long, often bearing a broad, 

 ear-shaped bracteole; connective very large, scutellate; anther cells narrow. 5 



"The leaves of seedlings and young trees (Emrick 20) are thinner, obovate 

 and sharply acuminate. On immature leaves of adult trees the pubescence is 

 thicker on both faces. 



b The clusters of stamens are at the branching points of the crests, the 

 isolated individuals scattered along the latter. The filaments are often adher- 

 ent to the bracteoles for part of their length. Morphologically the bracts and 

 the stamens seem to be equivalent; the filaments are flattened and membranous, 

 like the crest itself. Toward the margin of the receptacle the crests and 

 bracteoles disappear and the stamens issue directly from the floor of the 

 receptacle. Often the filament is the direct outgrowth of a bracteole. On the 

 bracteoles are sometimes seen anther cells adhering just in the same way as 



