Monographs Details: Telitoxicum
Authority: Barneby, Rupert C. & Krukoff, Boris A. 1971. Supplementary notes on American Menispermaceae. VIII. A generic survey of the American Tricilisisae and Anomospermeae. Mem. New York Bot. Gard. 22: 1-89.
Family:Menispermaceae
Scientific Name:Telitoxicum
Discussion:

Generitype: T. minutiflorum (Diels) Mold.

Drupes of Telitoxicum studied in relation to the current revision represent all known species except T. peruvianum, still known only from the staminate type.

Pistillate inflorescences (simply racemose) and drupes of Telitoxicum are essentially Uke those of Abuta. The drupe is ± 2.5-3.5 cm long, variably obUque at base, obovoid-oblong in general outline, with mealy-coriaceous exocarp 1-2.5 mm thick and (dry) almost no mucilaginous mesocarp. The endocarp is that of Abuta, but the secondary incised veinlets are very slender and only shallowly impressed. Endosperm and embryo of Abuta.

The genus must be closely related to Abuta, from which it differs in the presence of six petals in the staminate flower (flower [female] unknown), and in the pinnate venation of the leaf-blades. Leaves of Telitoxicum suggest those of some Anomospermum, but this genus differs in fruit-structure and in reduction of the pistillate inflorescence to a single flower. Staminate flowers of Telitoxicum and of Anomospermum sect. Elissarrhena are much alike. The androecium of Telitoxicum can be almost matched in some species of sect. Elissarrheim (especially A. bolivianum and A. solimoesanum), as well as in those Abuta which have free stamens.

Since Telitoxicum was disentangled from .Abuta and Anomospermum in 1938, no new species has been added to the genus and knowledge of its members has grown very slowly. Revision of all available material, among which are important recent accessions from Para collected by N. T. Silva, has confirmed and ampHfied the concept of T. glaziovii hitherto obscure. While much remains to be learned about all the species, especially their geographic range, a few words of general review summarizing what is now known may be useful in this context.

The species of Telitoxicum, with the exception of T. glaziovii, are readily sorted into two groups by means of correlated features of foliage and staminate inflorescence. In the smaUer group, consisting of T. minutiflorum and T. duckei, the upper leafsurface is distinctly (even though not very sharply) reticulate and has relatively numerous (mostly 7-9, rarely 10 pairs of) slightly elevated secondary nerves; the primary and greatly contracted secondary axes of the staminate inflorescence are minutely strigulose, not loosely pilosulous; and the very tiny flowers (unknown as yet in T. duckei) are borne on firm, relatively short pedicels, the longest of each cymule not over 3.5 mm long. The second group embraces all other species. Here the upper leaf-surface is smoother and usually highly lustrous, with often (but not always) fewer, always impressed secondary nerves; the axes of the staminate panicle are densely pilosulous; and the larger flowers are arranged in more effuse cymules, borne on capillary, flexuous pedicels up to 4-8 mm long. Telitoxicum glaziovii clearly belongs with the second group because of its inflorescence, virtually identical with that of T. krukovii, but the foliage is ambiguous, some old leaves having secondary nervation almost as superficial as in T. minutiflorum while others have the glossy surface and impressed venation of T. inopinatum. But we shall return to this subject further on.

Foliage of the first group is variable in outHne of the blades, which may be ovate-acuminate or oblong, sometimes subtruncate at base and apex, but there seems to be no way of sorting the leaf-types into meaningful categories, with the result that it is almost impossible to separate A. minutiflorum from A. duckei unless flowers are present. We do have, associated with fohage that could represent A. minutiflorum, two types of pistillate inflorescence, one with relatively slender, glabrate pedicels, and drupes very early glabrate, the other with stout pedicels and drupes all persistently strigulose. The glabrate type has traditionally (and no doubt correctly) been interpreted as pistillate A. minutiflorum; whether the other (from Vaupes, Colombia) is rightly associated with A. duckei, known with absolute certainty only from Amazonas and northwest Para, Brazil, cannot be stated positively. However, we adopt this interpretation provisionally as a working hypothesis until a more definite link between the sexes can be procured.

Taking into account the similarity in the foUage, one is obliged to question the existence in this group of two distinct species. The original concept of Anomospermum minutiflorum was based on a staminate plant at young anthesis, that of Abuta duckei on a staminate plant bearing mature inflorescences from which all flowers (which, had they been present, and petahferous, would not have passed as Abuta) had already dropped. All flowering T. minutiflorum collected subsequently is, by ill-chance, young, while the one subsequent staminate T. duckei (Froes 21296) is, Hke the type, past anthesis. The only known difference between the two species (disregarding the possibly irrelevant pistillate differences mentioned above) is the length of the pedicels, 0.7-2 mm long at early anthesis in T. minutiflorum, 1.8-3.5 mm long soon after anthesis in T. duckei. Specific status of T. duckei will remain somewhat insecure until staminate inflorescences bearing flowers at the same stage of development can be compared. Meanwhile identification of sterile material in this group can be made only by divination, for dispersal of the two species has not been worked out. The record of T. duckei from Bahia (Froes 12718) cannot be considered definite until confirmed by a flowering collection.

Approaching the second group we are on firmer ground. Easily detached from the mass is T. krukovii, beautifully characterized by its bullate leaf-blades, so formed by depression of the tertiary as well as the (5-10 pairs of) secondary nerves. In its staminate inflorescence and individual flower, with relatively large sepals all of nearly equal length, T. krukovii hardly differs from T. inopinatum or T. glaziovii, although there are minute differences in the inner perianth segments. The three remaining species are much alike in foliage, the usually lustrous, thick-textured leafblades having only the secondary nerves impressed (sometimes little so in T. glaziovii) and these comparatively few in number, mostly 4-6, rarely 7 pairs. Moreover the staminate inflorescences are superficially alike. The staminate flower of T. peruvianum, still known only from the type, is relatively small, with sepals differentiated into a short outer and longer inner cycle of three, whereas the sepals of the allopatric T. glaziovii and T. inopinatum are relatively large and of nearly equal length.

The two remaining species, T. glaziovii and T. inopinatum, are more closely akin than suggested originally (Brittonia 3: 44), where the former is associated in the key with T. minutiflorum and T. duckei, the latter with T. peruvianum, the emphasis being upon characters of foliage rather than flowers. However, staminate inflorescences of this pair are similar up to the petals; and the foUage, assuming that we rightly refer to T. glaziovii several collections from the lower Amazon in Para, in particular from Rios Jari and Moju, can be deceptively similar also. In general, however, the always glossy and (dry) discolored leaves of T. inopinatum, with secondary veins sharply depressed, are relatively small by comparison with those of T. glaziovii, which vary, however, from glossy to dull, from deep brown to olivaceous, and from depressedveiny to almost plane. The Hnk between the plane and depressed-veiny leaf-types has been estabUshed through a recent gathering from Rio Jari (Silva 2657) in which a relatively ample, olivaceous, depressed-veiny leaf gives rise to the inflorescence with sac-like petals of T. glaziovii. While more numerous examples of staminate inflorescences (at present we have only two of each species) are needed before the constancy of petal-shape can be established, we feel it Ukely, on phytogeographic grounds, that we are deaUng with two distinct entities, T. inopinatum being a plant of patches of forests in savannas in Guiana, whereas T. glaziovii usually occurs in high Amazonian forest on terra firme. As mentioned parenthetically in the list of specimens under T. glaziovii, we now suspect that the type locality, unknown in 1938, was actually near Santarem in western Para, from which we have a sterile specimen also very similar in facies. This supposition harmonizes with the dispersal data derived from modern collections.

The staminate inflorescence is a prerequisite for identification of Telitoxicum down to species, a circumstance which our key reflects. The uniform character of the drupe renders it useless for diagnostic purposes. Pubescence of the stem and leaf is likewise of little service, the densely tomentulose young stems of T. glaziovii becoming early glabrous, while the petiole in T. krukovii may be either densely rusty-setulose or entirely hairless, perhaps depending partly on age and partly on position and exposure. The exact number of secondary veins in the leaf-blade has proved too variable to have dependable diagnostic value. In T. krukovii there m a y be as few as five or as many as ten pairs. The type of T. glaziovii has two leaves, one with six, one with seven pairs. Most of the material of T. glaziovii from eastern Para has four to six pairs; those of T. inopinatum mostly four or five, rarely up to seven pairs.