[298]

May 28th ─ 31' 1878

Opuntia basilaris

Seedlings raised at Kew. Cotyledons largely well developed in length, breadth & thickness (not protected by Bloom) length of .9 of inch, breadth of .22 & thickness .15 Hypocotyl rather short, .45 of inch, high almost cylindrical .19 in diameter. These measurements made at close of observations on morning of 31st a tr vestige of incipient spines stand between bases of Cots (Used)

The hypocotyl not being enlarge in relation relation to large cotyledons (Hypocotyl certainly not in the least spherical) interesting in relation to Various other Cacteæ with much reduced Cots & more or less thickened hypocotyls)

Keep—

During morning of 28th A glass filament attached longitudinally to 1 Cot with bead & mark below, illuminated feebly from above, or k observed in Hot House— Tracing Movement of bead at end of filament magnified 30 times — Actual distance moved by bead during 29th .14 of inch. I was much interested in observing this plant as I thought, considering nature of mature mature plant non none so little likely to move. But tracing shows that made complete ellipse during 29th;

[insertion:] This part used

next day moved from some unknown cause in one direction, making making, however in its course a small ellipse. At first on 28th moved first in one direction & then at night in another course, but Tracing too much magnified, so observation Tracing began at 4° 45' P.m. 28th & continued till 11° a.m on 31th. — As glass filament attached to Cot. & Hypocotyl (not

(over

[298v]

Hypoct. certainly not in the least spherical)

(Opuntia)

not secured) tracing shows their confined movement; but the chief movement was cleary that of the Hypocotyl. The Cots. move up & down, whereas the longer axis of ellipse in Tracing is at nearly right angle, to a line joining two cotyledon; & their movement, wd make lengthen length or or shorten a line at right angles to this longer axis. The Cots. though so thick move a little up & down for at 10° 15' P.m. they stood 10° higher above horizon than they did at noon & at 4° P.m. Used

(Lettington asserts that Cots. of Opuntia nigricans whilst young closed at night, but they did not do so when older.)

[insertion:] nor when young— a mistake

By the time the stem of the seedling has become developed into 2 or 3 little globular head covered with spines, the Cots have withered & dropped off leaving scars behind them, & now the cylinder hypocotyl is has become greatly thickened & covered with smooth, tough? yet pale brown skin; it but tapers downward & with the lower part apparently has been drawn int the ground─