10 THE GENUS PHORADENDRON 
INFLORESCENCE.—The essential characters of Phoradendron in its 
group of Loranthaceous genera are chiefly its axillary spikes of small 
unisexual and monochlamydeous sessile flowers (Pl. 5-6), often sunken 
. in hollows of the frequently swollen internodes of the rachis and nor- 
mally trimerous (Pl. 7), with 2-celled longitudinally dehiscent anthers. 
A very few species, like P. cymosum, present the phenomenon of a termi- 
nal spike corresponding to the 1- or few-flowered eyme of the old world 
Viscum, but in addition to axillary spikes. Except in the species taken 
by Hooker for falcatum, the receptacular cups, which range from so shal- 
low as hardly to surround the base of the flower to a depth covering a 
noticeable part of the mature fruit, are essentially even on their margin; 
but in this species the eup is sometimes parted so as to present the ap- 
pearance of a deeply divided calyx. The flowers,—with a small vestigial 
nectar gland and apparently adapted to pollination by such short- 
tongued insects as flies and small bees,*—are usually yellowish green 
when expanded, but in P. Brittonianum and some of its relatives the 
sepals are blood-red even before anthesis. Some species are known to be 
apogamoust and apogamy is to be expected in many others, a cireum- 
stance very probably connected, as in Taraxacum and Hieracium, with 
polymorphism or close affinity in species as now understood. So far as 
T know, polyembryony, recorded for Viscum and Arceuthobobium or 
Razoumofskya,t has not yet been observed in Phoradendron. 
While the number of internodes composing a flowering spike varies 
in most species it usually varies within small limits, and its mean appears 
to be available in most cases in the recognition of a species. Contrasts 
are afforded by P. Libocedri, P. cuneifolium, P. emarginatum, P. flaves- 
cens, P. polygynum, ete. Sometimes corresponding to the number of 
joints, sometimes to their length, and sometimes to both, the length of 
the spike also presents differences of taxonomic value if used not too 
arbitrarily, e. g., in P. emarginatum, P. flavescens, P. macrotomum, and 
P. polygynum. In all of our own species the plants are strictly dioe- 
cious; and, as a rule, staminate spikes are longer than pistillate and bear 
more flowers (Pl. 5). This is known to be true also of a number of 
tropical species, such as P. Watti; in others, prevailinely if not exclu- 
sively staminate and pistillate spikes showing something of the same 
dimorphism occur monoeciously on the same plant. Though usually not 
too closely applicable as between related species, the number and 
*Honey and pollen are said to be gathered from some species:—Richter, Bull. 
|. 217, Calif. Exper. Sta.—Sholl, Bull. 102, Texas Exper. Sta. The staminate flowers 
of P. villosum are said to have the odor of pond lilies, by Piper and Beattie, Flora 
of the Northwest Coast, p. 124. 
Cf. York, Bot. Gaz. vol. 56. p. 201. 
+Cf. Weir, Phytopathology. vol. 4. p. 385. 
