391(5] Brandt: Notes on Trillium 49 



h. Trillium ovatum 



Practically all the points noted above in the description of the 

 active period above ground peculiar to Trillium sessile var. giganteum 

 hold in modified form for T. ovatum. It might be recalled that T. 

 ovatum is a pedunculate species in contrast to T. sessile var. gigan- 

 teum, which is sessile, and that previous to anthesis the flower is white. 

 Growth is much more rapid, the shoot attaining full height in a week. 

 The flower opens before the leaves are fully spread and the petals 

 have faded and fallen by the time the plant has been out of the ground 

 a month. The species is distinctly protandrous and is doubtless ento- 

 mophilous, as Robertson (1896) states is the case in T. grandiflorum 

 and T. erecium. Little need be said about the fruit, which usually 

 ripens in May, except that dehiscence is septicidal, beginning at the 

 apex and extending to the base. The seeds, which are smaller and 

 darker brown than those of T. sessile var. giganteum, sometimes num- 

 ber more than 300. They also are myrmecophilous, as Robertson 

 (1897) reports for T. recurvatum^ 



2. BELOW GROUND 

 a. Trillium sessile var. giganteum 



With the beginning of growth in February the bud-sheaths lengthen 

 sufficiently to appear a few centimeters above ground and protect the 

 young leaves as they push up through the soil. They are separated 

 by the rapid gi'owth of the young shoots and gradually disappear. 

 The axillary "sheaths," or spongy bodies at the bases of the main 

 sheaths, lengthen but little, but appear to remain alive quite late in 

 the flowering season. At this same time the apex of the rootstock 

 begins to grow and to lay down new stem-buds while the young buds 

 whose growth was suspended resume development, with the exception 

 of the first bud, which now shrivels up, as previously stated. 



The young stem is at first a short cylinder of undifferentiated 

 parenchyma. Soon the lateral structures make their appearance in 

 acropetal succession. The young axis is produced beyond the point 

 of insertion of foliage primordia so that the young sepals slightly 

 overtop them at first (pi. 7, figs. 2 and 5). During early development 

 the floral organs apparently grow more rapidly than the foliage leaves, 

 so that a bud examined in ]\Iay would give one the impression that the 

 sepals begin their growth before the foliage leaves. 



By May 1, in at least the most advanced bud, sepals and petals 

 have completely closed over the parts within (pi. 7, figs. 3 and 6). 



