THE PULP OF CACTUS FRUIT. 235 
Mrs. Major Sumner. This handsome species extends northward to the plains of Colorado and Pike’s Peak, covering 
extensive tracts. Remarkable for its horizontal, often whorled branches; purple flowers, 2-24 inches in diameter ; 
vary often with some spiny bristles, which at maturity disappear. The skeleton — as the cactus wood is ra 
faneifully called after the soft tissues have rotted away — forms a heavy, hollow cylinder, with regular rhombic holes 
or meshes corresponding to the tubercles and spine-bunches of the plant, and makes excellent canes 
This species is closely allied to the Mexican O. imbricata and O. decipiens, — arborescens being the northern, 
larger-flowered form, — but the seeds are different 
. (CyLinpropuntIA) BieELovil, Engelm. (Pacif. Rail. Rep. 4, Bot. 50, tab. 19). An erect, bushy [131] 
plant, 10-12 feet high, with oval or subcylindric joints, bearing on short oval tubercles 3-5 large (1 inch long) 
and many smaller spines, the larger ones loosely covered by glistening whitish sheaths ; purple flowers, small, 1 inch 
wide ; fleshy greenish es ; humerous small and very irregular seeds, or often abortive ; wood a wide fragile tube, 
with short meshes. 
O. (CYLINDROPUNTIA) TESSELLATA, Engelm. a bushy, from a stout trunk, with solid wood, sometimes 
several inches thick ; ultimate branches as thick as a swan’s quill, covered with angular, flattened, ashy-gray tubercles, 
the uppermost bearing at their upper end single, long, loosely yellow-sheathed spines; flowers small (about ? of an 
inch wide), yellow; small fruit, oval, covered with long, soft, brown bristles. Pacif. Rail. Re = 
On both sides of the Lower Colorado River, 6-7 feet high. The yellow shining spines, crowded on the upper nee of 
each year’s growth, together with the scale-like tubercles, give the plant a singitler and striking appearance. 
There are several other cylindric Opuntie in Arizona not collected in these Expeditions, and for the most part 
only imperfectly known. It is desired to direct attention to this interesting group, which, on account of the bulky 
forms and forbidding armament, are too much shunned by travellers. — O. echinocarpa, Engelm. & Bigelow, is a low 
and very spiny bush, with yellowish flowers and dry spiny fruit. — O. acanthocarpa, Engelm. & Bigelow, is taller, a 
elongated tubercles, or rather ridges, copper-colored flowers, and dry fruit bearing few but stouter spines. — 0. m 
lata, Schott, and O. fulgida, Engelm. & Bigelow, are allied to O. Bigelovii, with thick tubercles or prominent a 
the former with small, the other with numerous long and shining sheathed spines ; fruit often abortive. speci- 
mens, With flower, fruit, and good seed of the same plant (so that mixing species and forms may be avoided), are very 
desirable, as we know scarcely anything more about them than what the botanists of the Mexican Boundary Com- 
mission (often at the most unfavorable season) could find out twenty-five years ago. — 0. leptocaulis, D.C. (O. frutescens, 
Engelm.), the most slender Opuntia known, bushy, with branches like pipe-stems, small yellow flowe 
red, somewhat fleshy berries, is common from North Mexico, through Texas, to Arizona. It has been said that [132] 
its flowers, contrary to the habit of the genus (which has diurnal flowers, 7. ¢. open in sunlight), are nocturnal, 
which, however, is now positively denied. 
XIV. THE PULP OF CACTUS FRUIT. 
From TRANSACTIONS OF THE St. Louris ACADEMY oF Science, Vou. II., Ocroper, 1861. 
ZUCCARINI, than whom none better understood the morphology, as well as the systematic [166] 
characters of the Cactacez, had already in the year 1845 (Plant. nov., fase. 5, pag. 34) expressed 
the opinion that in Cactaceze, as well as in Cucurbitacez, the funiculi assisted in forming the pulp 
of the fruit. Schleiden (Grundziige, ed. 3, p. 408) ascribes the pulp of Mamillaria to an arillus, dis- 
solving into single juicy cells. Gasparrini, in his extended but rather odd description of the Opuntiz 
fruit (Osservazioni, 1853, p. 20), also considers the pulp as a peculiar sort of an arillus. I had 
long since come to the conclusion, especially after examining the somewhat dry fruits of Cereus ceespi- 
tosus and Echinocactus setispinus, that the funiculi alone constitute the pulp, and in Cact. Mex. Bound. 
tab. 20, fig. 12, I had figured the enlarged funiculi of the latter plant. 
The Cactus fruit is usually succulent ; only some Echinocacti and some Opuntiz are known to 
bear dry fruits. The succulent fruit consists of the fleshy walls of the fruit itself, originating from 
the carpel and the adhering calyx (or part of the stem, as Zuccarini will have it), coalescing and 
forming a homogeneous mass, and of the juicy pulp, in which latter the seeds are imbedded. In 
