TREES AND SHRUBS 



ACER SmUOSUM, Kehd. 



Acer sintjosum, n. sp. 



Leaves suborbicular or semiorbicular in outline, broader than long, usually broadly cordate at 

 the base, the wide sinus with a broad V-shaped projection at the insertion of the petiole, formed 

 by the lateral veins diverging at right angles to each other and for some distance forming the mar- 

 gin of the leaf, from 3 to 7, usually from 3.5 to 4 centimetres long and from 3.5 to 7.5 centi- 

 metres broad, from three- to five-lobed, with short triangular-ovate to triangular-oblong obtuse lobes 

 entire or on vigorous shoots with a few short teeth ; when they unfold glabrous and purplish 

 above, loosely hairy beneath, soon becoming glabrous, at maturity dark yellow-green and lustrous 

 above, below pale but not glaucous, reticulate and glabrous except in the axils of the primary 

 veins, prominently three- to five-nerved, the basal nerves of the five-nerved leaves merging into 

 the upper lateral nerves before reaching the base; petioles glabrous, slender, from 1.5 to 3.5 

 centimetres in length. Flowers appearing with the leaves on slender glabrous pedicels from 

 1.5 to 3.5 centimetres long, in from three- to eight-flowered nearly sessile corymbs ; calyx broadly 

 campanulate or cupulate, yellowish, about 2 millimetres high and 3.5 millimetres wide, with short 

 semiorbicular lobes ciliate on the margin, or sometimes campanulate, higher than wide, persistent 

 under the fruit ; petals wanting ; stamens usually six, in the staminate flowers with slender fila- 

 ments exceeding the calyx, from 3 to 4 millimetres long, in the pistillate flowers as long or 

 shorter than the calyx ; ovary with scattered long white hairs ; style divided below the middle 

 into two slender spreading stigmas. Fruit glabrous with nearly horizontally spreading nutlets 

 from 7 to 8 millimetres long and about 5 millimetres broad, strongly convex, smooth, pale yellow- 

 ish brown, wings curved upward, from 1.6 to 1.8 centimetres long and about 8 millimetres wide. 



A shrub or tree, with a trunk covered with pale grayish bark, and slender branchlets at first 

 light green and glabrous, becoming pale red-brown during their first season and marked by mi- 

 nute pale lenticels, purplish brown the second year and ultimately dull grayish brown. Winter- 

 buds dark brown, small, obtusish, with six pairs of outer scales and several inner accrescent scarlet 

 or pink scales, linear-oblong and from 1.5 to 3 centimetres long when fully grown. 



Texas : Banks of the Cibolo River near Boerne, Boerne County, S. H. Hastings, 1911 (type, 

 fruit), June 24, 19j.O (fruits), C. S. Sargent, March 27, 1887 ; from a cultivated tree in the 

 town of Boerne, C. S. Sargent, March 25, 1911, April 1, 1913. 



This species is most closely related to Acer fioridanum Pax, which is easily distinguished by the pubescent and glau- 

 cous under surface of its larger leaves with more or less dentate lobes and with a narrow sinus at the base. It is also 

 near Acer mexicanum Gray, which, like our species, has the leaves nearly glabrous below at maturity, but they are 

 truncate or rounded at the base and glaucescent below ; the lobes, too, are more or less toothed as they are in Acer fiori- 

 danum, and the wings of the fruit are upright and parallel. 



This species is specially interesting because it is the only Sugar Maple with leaves in which the middle of the sinus 

 is occupied by a projection formed by the veins of the two upper lobes which here form its margin. Its geographical 

 isolation is also interesting, for Acer lencoderme Ashe on the Red River, Acer grandidentatum Nuttall on the moun- 

 tains of the extreme western part of Texas, and Acer mexicanum Gray in Nuevo Leon are its nearest neighbors among 

 the Sugar Maples. 1 



1 The following varieties of allied species may be here characterized. 



;s covered with a more or less densely vi 



