162 BOTANICAL GAZETTE [MARCH 
roots which develop from the nodes (between the two leaves) and from 
the internodes. A small rosette of green leaves appears at the end 
of the first season, and this little shoot is the only portion of the 
seedling that winters over; it is developed from the axil of one of 
the basal leaves, and consists of a short, but very distinct, internode 
above ground and is terminated by a rosette of leaves, all opposite 
and with the internodes hardly perceivable. During the next spring 
an inflorescence becomes developed terminating the shoot; while at 
the same time numerous buds become visible in the axils of the leaves 
of the rosette, each producing a short decumbent stolon of one or 
two internodes, terminated by a dense rosette of green leaves. The 
stolons being above ground, all the leaves possess distinct petioles 
and blades. Secondary roots appear, as described above, at various 
places; they are very thin, of whitish color, and branch freely. The 
lateral shoot thus represents two stages of growth: a purely vegetative 
one during the winter, and a floral one during the next spring; while 
the primary shoot of the seedling blooms without being preceded by 
other leaves than those at the base of its own stem, including the 
cotyledons. Our species thus resembles an annual plant in blooming 
in the first year; a biennial in producing a rosette of leaves to winter 
over and to become terminated by an inflorescence in the next year; 
and finally it remains as a perennial by the continuous development 
of leafy shoots and inflorescences.s The inflorescence is a cyme of 
the dichasium type, but relatively few-flowered. These introductory 
remarks are to show that the roots are of short duration, that the 
stolons are above ground, and that the leaves are either cauline or 
basal, the latter constituting an over-wintering rosette. 
The roots.—As stated above, the secondary roots are very slender; 
they are very hairy and the epidermis covers directly a cortical paren- 
chyma of three, thin-walled, compact strata. An endodermis with 
the cell walls moderately thickened surrounds the central cylinder, in 
which the pericambium is continuous and thin-walled. These roots 
are diarch, the two rays of the hadrome meeting in the center, alter- 
5A near ally of H. coerulea is H. serpyllifolia Michx., but in this species the 
vegetative shoots do not develop as rosettes of leaves, since all the internodes are 
stretched, with the leaves remote. In H. rotundifolia Michx. the habitus is much 
_the same as in H. serpyllijolia, but the plant is more robust and the flowers are almost 
sessile and single in the leaf axils. 
