302 



Mr. Tieleas(;'s life- studies of Y. icMppJei have added luateiially to our 

 understaudiug of its floral cliaracteristics. The anther cells, on dehisc 

 ing, contract so as to expose the pollen freely, but the contents of each 

 cell forms a " rather consistent, two-lobed moist mass, which is held l)y 

 its lower part, but protrudes prominently from the open anther." The 

 ovary is free from the longitudinal depressions which in the other Yuc- 

 cas usually correspond with the appressed stamens. The capitate 

 stigma is slightly indented at the center ''and covered with long, hya- 

 line, delicate papilhe, which are always moist with abmuhmt secretion, 

 that at length becomes almost gelatinous over the middle of the stigma." 

 He found the nectar apparatus well developed, the septal glands though 

 narrow reaching commonly to the base of the ovary, with a conducting 

 groove of corresponding size. The glands are also, though smaller, 

 more active than in most other species of Yucca studied by him. Prof. 

 Trelease also notes that the characteristics of this flower would seem to 

 make it easily self fertilizable, and remarks on the exceptional occur- 

 rence in the lower part of the C'ajon Pass of a few plants with more or 

 less abundant, i^artly developed, but unusually diminutive capsules, in 

 which no evidences of Pronuba action were to be found, and this, added 

 to the experiment made by Mr. Coquillett, would seem to indicate 

 that where Pronuba is absent wMppJei has the same exceptionally lim- 

 ited power of fructification, Avhether by self-pollination or pollination by 

 other agents, that we know to be possessed by uloifolia among the 

 true Yuccas. Recognizing this possibility. Prof. 'I'release was some- 

 what surprised to find that, with the single exception which he noted, 

 no fruit, among all his observations, was discovered which did not 

 clearly show the work of Pronuba. 



From his account, as well as that of Mr. Coquillett, it ap])ears evi- 

 dent that Pronuba maculofa, in accordance with the greater tendency 

 of the flowers of whippJei to open during the day, is more diurnal in 

 habit than Promiha ynecasella, carrying on the acts of oviposition and 

 pollination during the day. Further, unlike the other Pronubas so far 

 known, this species rests with the head toward the stigma, and when 

 disturbed is very apt to drop suddenly from the flcnver and take wing. 

 I can not do better than quote verbatim Mr. Trelease's interesting 

 account of the act of pollination, that of ovii)osition being, as already 

 stated, absolutely the same as in yuceaseUa. 



Wheu tlie moth is iibout to deposit an egg slie usually moves about iu the lower 

 part of the flower much as the other species do, commonly dragging the tip of the 

 ovipositor along the parts she walks on as if wiping off extruded secretion, but also 

 seemingly using it as a tactile organ while she assumes the position best suited to 

 oviposition, which is nearly the sanae as that taken while at rest. Standing on the 

 side of the pistil, she then bends the abdomen sharply forward so as to bring the 

 ovipositor to about the middle of the ovary, Avhich she pierces at the thinnest part, 

 namely, about 1'""' from the septal groove. As a general thing not more than six 

 eggs are laid in a given pistil — one on either side of each septum — and frequently 

 the number is smaller than this, so that even if they all hatch, which is not likely 

 to be the case, there is rarely more than one larva to each tier of seeds, and con- 



